Advanced Materials and Concepts for Portable Power Fuel Cells · 2010-10-05 · Advanced Materials...
Transcript of Advanced Materials and Concepts for Portable Power Fuel Cells · 2010-10-05 · Advanced Materials...
11DOE Kick-off Meeting Washington DC September 28 2010
Fuel Cell Projects Kick-off Meeting Washington DC ndash September 28 2010
Advanced Materials and Concepts for Portable Power Fuel Cellsfor Portable Power Fuel Cells
Piotr Zelenay
Los Alamos National LaboratoryLos Alamos National Laboratory Los Alamos New Mexico 87545
This presentation does not contain any proprietary confidential or otherwise restricted information ndash
t t
Overview
Timeline
bull Start date September 2010 bull End date Four-year duration
BudgetBudget
bull Total funding estimate ndash DOE share $3825K
Contractor share $342K$342Kndash Contractor share bull FY10 funding received $250K bull FY11 funding estimate $1000K
Barriers
bull A Durability (catalyst electrode)(catalyst electrode)
bull B Cost (catalyst membrane MEA) bull C Electrode Performance
(f(fuell oxidatiion kikinetiics)id )
Partners ndash Principal Investigators
Brookhaven National Laboratory
ndash Radoslav Adzic
University of California RiversideUniversity of California Riverside
ndash Yushan Yan
Virginia TechVirginia Tech
ndash James McGrath
Johnson Mattheyy Fuel Cells ndash Nadia Permogorov
Smart Fuel Cell Energy
ndash Verena Graf
Oak Ridge National Laboratory
ndash Karren More
DOE Kick-off Meeting Washington DC ndash September 28 2010 22
t t
t
= 1 = -
Relevance Objective amp Targets
Objective Develop advanced materials (catalysts membranes electrode structures b l d bli ) d f l ll ti bl f f lfillimembrane-electrode assemblies) and fuel cell operating concepts capable of fulfilling
cost performance and durability requirements established by DOE for portable fuel cell systems assure path to large-scale fabrication of successful materials
Project technical targets bull System cost target $3W bull Performance target Overall fuel conversion efficiency (ηΣ) of 20-25 kWhL
F h l f lFor methanol fuel (1) 20-25 kWhL rarr ηΣ = 042-052 (16-20times improvement over the state of the art ~ 1250 kWhL) (2) If ηfuel = 096 ηBOP= 090 Vth=121 (at 25degC)
V = V [ηΣ ((ηη η ] 06 07 V The ultimate project goalVcell Vth [η fuel ηBOP ))-1] = 0 6-0 7 V The ultimate project goal
DOE Kick-off Meeting Washington DC ndash September 28 2010 33
Approach Focus Areas
bull DMFC anode research minus cattallysts with iith improvedd ac titivitity andd reducedd cost (BNL JMFCJMFC LANL)t d t (BNL LANL) minus development of catalysts with improved durability (LANL JMFC)
bull Alternative fuels for portable fuel cells minus ethanol oxidation electrocatalysis (BNL LANL) minus dimethyl ether research (LANL)
bull Innovative electrode structures for better activityy and durabilit yy ((UCR)) bull Hydrocarbon membranes for lower MEA cost and enhanced fuel cell
performance (VT LANL) minus block copolymersblock copolymers
minus copolymers with cross-linkable end-groups
bull Characterization performance and durability testing multi-cell device minus advanced materials characterization (ORNL BNL LANL) minus MEA performance testing (LANL JMFC SFC) minus durability evaluation (LANL JMFC SFC) minus five-cell stack (SFC)
DOE Kick-off Meeting Washington DC ndash September 28 2010 44
- deg deg
05 M MeOH in 01 M HClO4
PtRuC (commercial)) 10 nmol Pt + 10 nmol Ru
mA
μg Pt
)
4
6
8
55
DMFC Anode Research Activity
bull DMFC Vth=121 V (at 25degC) fuel specific energy 61 kWhkg
bull CH OH + 2H O rarr CO + 6H+ + 6e- E cong 002 V (at 25 C)CH3OH + 2H2O rarr CO2 + 6H+ + 6e Edeg cong 0 02 V (at 25degC)
bull Reduction of methanol-oxidation overpotential through atomic-level control of PtRu nanoparticle synthesis minus optimal Pt atom ensembles for MeOH adsorption and abstraction of H atomsoptimal Pt-atom ensembles for MeOH adsorption and abstraction of H atoms minus adequate Ru coverage for providing OH and O species for CO oxidation minus submonolayer of Pt on Ru nanoparticles through galvanic replacement of Cu adlayers
bull Catalysts on oxide supportsCatalysts on oxide supports (e g(eg NbONbO2 SnOSnO2 MagneacuteliMagneacuteli phases)phases)bull
minus cation-adsorptionreductiongalvanic-displacement method minus significant reduction in Pt loading expected
10
adsorption
Electrochemicalor chemical reductionadsorption
Electrochemicalor chemical reductionadsorption
Electrochemical or chemical reduction
PtRuC (BNL) 033 nmol Pt + 045 nmol Ru
j (m
0
2
4
-04 -02 00 02 04 06 08 10 12C ti d ti d ti l i di l t th d
Immersion in Pt solution
Further Ptdeposition by electrochemical or chemical methodsreplacement
Immersion in Pt solution
Further Pt deposition by electrochemical or chemical methodsreplacementreplacement
Cation-adsorptionreductiongalvanic-displacement method of metal deposition on oxide surfaces EAgAgCl (V)
DOE Kick-off Meeting Washington DC ndash September 28 2010
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
t t
Overview
Timeline
bull Start date September 2010 bull End date Four-year duration
BudgetBudget
bull Total funding estimate ndash DOE share $3825K
Contractor share $342K$342Kndash Contractor share bull FY10 funding received $250K bull FY11 funding estimate $1000K
Barriers
bull A Durability (catalyst electrode)(catalyst electrode)
bull B Cost (catalyst membrane MEA) bull C Electrode Performance
(f(fuell oxidatiion kikinetiics)id )
Partners ndash Principal Investigators
Brookhaven National Laboratory
ndash Radoslav Adzic
University of California RiversideUniversity of California Riverside
ndash Yushan Yan
Virginia TechVirginia Tech
ndash James McGrath
Johnson Mattheyy Fuel Cells ndash Nadia Permogorov
Smart Fuel Cell Energy
ndash Verena Graf
Oak Ridge National Laboratory
ndash Karren More
DOE Kick-off Meeting Washington DC ndash September 28 2010 22
t t
t
= 1 = -
Relevance Objective amp Targets
Objective Develop advanced materials (catalysts membranes electrode structures b l d bli ) d f l ll ti bl f f lfillimembrane-electrode assemblies) and fuel cell operating concepts capable of fulfilling
cost performance and durability requirements established by DOE for portable fuel cell systems assure path to large-scale fabrication of successful materials
Project technical targets bull System cost target $3W bull Performance target Overall fuel conversion efficiency (ηΣ) of 20-25 kWhL
F h l f lFor methanol fuel (1) 20-25 kWhL rarr ηΣ = 042-052 (16-20times improvement over the state of the art ~ 1250 kWhL) (2) If ηfuel = 096 ηBOP= 090 Vth=121 (at 25degC)
V = V [ηΣ ((ηη η ] 06 07 V The ultimate project goalVcell Vth [η fuel ηBOP ))-1] = 0 6-0 7 V The ultimate project goal
DOE Kick-off Meeting Washington DC ndash September 28 2010 33
Approach Focus Areas
bull DMFC anode research minus cattallysts with iith improvedd ac titivitity andd reducedd cost (BNL JMFCJMFC LANL)t d t (BNL LANL) minus development of catalysts with improved durability (LANL JMFC)
bull Alternative fuels for portable fuel cells minus ethanol oxidation electrocatalysis (BNL LANL) minus dimethyl ether research (LANL)
bull Innovative electrode structures for better activityy and durabilit yy ((UCR)) bull Hydrocarbon membranes for lower MEA cost and enhanced fuel cell
performance (VT LANL) minus block copolymersblock copolymers
minus copolymers with cross-linkable end-groups
bull Characterization performance and durability testing multi-cell device minus advanced materials characterization (ORNL BNL LANL) minus MEA performance testing (LANL JMFC SFC) minus durability evaluation (LANL JMFC SFC) minus five-cell stack (SFC)
DOE Kick-off Meeting Washington DC ndash September 28 2010 44
- deg deg
05 M MeOH in 01 M HClO4
PtRuC (commercial)) 10 nmol Pt + 10 nmol Ru
mA
μg Pt
)
4
6
8
55
DMFC Anode Research Activity
bull DMFC Vth=121 V (at 25degC) fuel specific energy 61 kWhkg
bull CH OH + 2H O rarr CO + 6H+ + 6e- E cong 002 V (at 25 C)CH3OH + 2H2O rarr CO2 + 6H+ + 6e Edeg cong 0 02 V (at 25degC)
bull Reduction of methanol-oxidation overpotential through atomic-level control of PtRu nanoparticle synthesis minus optimal Pt atom ensembles for MeOH adsorption and abstraction of H atomsoptimal Pt-atom ensembles for MeOH adsorption and abstraction of H atoms minus adequate Ru coverage for providing OH and O species for CO oxidation minus submonolayer of Pt on Ru nanoparticles through galvanic replacement of Cu adlayers
bull Catalysts on oxide supportsCatalysts on oxide supports (e g(eg NbONbO2 SnOSnO2 MagneacuteliMagneacuteli phases)phases)bull
minus cation-adsorptionreductiongalvanic-displacement method minus significant reduction in Pt loading expected
10
adsorption
Electrochemicalor chemical reductionadsorption
Electrochemicalor chemical reductionadsorption
Electrochemical or chemical reduction
PtRuC (BNL) 033 nmol Pt + 045 nmol Ru
j (m
0
2
4
-04 -02 00 02 04 06 08 10 12C ti d ti d ti l i di l t th d
Immersion in Pt solution
Further Ptdeposition by electrochemical or chemical methodsreplacement
Immersion in Pt solution
Further Pt deposition by electrochemical or chemical methodsreplacementreplacement
Cation-adsorptionreductiongalvanic-displacement method of metal deposition on oxide surfaces EAgAgCl (V)
DOE Kick-off Meeting Washington DC ndash September 28 2010
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
t t
t
= 1 = -
Relevance Objective amp Targets
Objective Develop advanced materials (catalysts membranes electrode structures b l d bli ) d f l ll ti bl f f lfillimembrane-electrode assemblies) and fuel cell operating concepts capable of fulfilling
cost performance and durability requirements established by DOE for portable fuel cell systems assure path to large-scale fabrication of successful materials
Project technical targets bull System cost target $3W bull Performance target Overall fuel conversion efficiency (ηΣ) of 20-25 kWhL
F h l f lFor methanol fuel (1) 20-25 kWhL rarr ηΣ = 042-052 (16-20times improvement over the state of the art ~ 1250 kWhL) (2) If ηfuel = 096 ηBOP= 090 Vth=121 (at 25degC)
V = V [ηΣ ((ηη η ] 06 07 V The ultimate project goalVcell Vth [η fuel ηBOP ))-1] = 0 6-0 7 V The ultimate project goal
DOE Kick-off Meeting Washington DC ndash September 28 2010 33
Approach Focus Areas
bull DMFC anode research minus cattallysts with iith improvedd ac titivitity andd reducedd cost (BNL JMFCJMFC LANL)t d t (BNL LANL) minus development of catalysts with improved durability (LANL JMFC)
bull Alternative fuels for portable fuel cells minus ethanol oxidation electrocatalysis (BNL LANL) minus dimethyl ether research (LANL)
bull Innovative electrode structures for better activityy and durabilit yy ((UCR)) bull Hydrocarbon membranes for lower MEA cost and enhanced fuel cell
performance (VT LANL) minus block copolymersblock copolymers
minus copolymers with cross-linkable end-groups
bull Characterization performance and durability testing multi-cell device minus advanced materials characterization (ORNL BNL LANL) minus MEA performance testing (LANL JMFC SFC) minus durability evaluation (LANL JMFC SFC) minus five-cell stack (SFC)
DOE Kick-off Meeting Washington DC ndash September 28 2010 44
- deg deg
05 M MeOH in 01 M HClO4
PtRuC (commercial)) 10 nmol Pt + 10 nmol Ru
mA
μg Pt
)
4
6
8
55
DMFC Anode Research Activity
bull DMFC Vth=121 V (at 25degC) fuel specific energy 61 kWhkg
bull CH OH + 2H O rarr CO + 6H+ + 6e- E cong 002 V (at 25 C)CH3OH + 2H2O rarr CO2 + 6H+ + 6e Edeg cong 0 02 V (at 25degC)
bull Reduction of methanol-oxidation overpotential through atomic-level control of PtRu nanoparticle synthesis minus optimal Pt atom ensembles for MeOH adsorption and abstraction of H atomsoptimal Pt-atom ensembles for MeOH adsorption and abstraction of H atoms minus adequate Ru coverage for providing OH and O species for CO oxidation minus submonolayer of Pt on Ru nanoparticles through galvanic replacement of Cu adlayers
bull Catalysts on oxide supportsCatalysts on oxide supports (e g(eg NbONbO2 SnOSnO2 MagneacuteliMagneacuteli phases)phases)bull
minus cation-adsorptionreductiongalvanic-displacement method minus significant reduction in Pt loading expected
10
adsorption
Electrochemicalor chemical reductionadsorption
Electrochemicalor chemical reductionadsorption
Electrochemical or chemical reduction
PtRuC (BNL) 033 nmol Pt + 045 nmol Ru
j (m
0
2
4
-04 -02 00 02 04 06 08 10 12C ti d ti d ti l i di l t th d
Immersion in Pt solution
Further Ptdeposition by electrochemical or chemical methodsreplacement
Immersion in Pt solution
Further Pt deposition by electrochemical or chemical methodsreplacementreplacement
Cation-adsorptionreductiongalvanic-displacement method of metal deposition on oxide surfaces EAgAgCl (V)
DOE Kick-off Meeting Washington DC ndash September 28 2010
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Approach Focus Areas
bull DMFC anode research minus cattallysts with iith improvedd ac titivitity andd reducedd cost (BNL JMFCJMFC LANL)t d t (BNL LANL) minus development of catalysts with improved durability (LANL JMFC)
bull Alternative fuels for portable fuel cells minus ethanol oxidation electrocatalysis (BNL LANL) minus dimethyl ether research (LANL)
bull Innovative electrode structures for better activityy and durabilit yy ((UCR)) bull Hydrocarbon membranes for lower MEA cost and enhanced fuel cell
performance (VT LANL) minus block copolymersblock copolymers
minus copolymers with cross-linkable end-groups
bull Characterization performance and durability testing multi-cell device minus advanced materials characterization (ORNL BNL LANL) minus MEA performance testing (LANL JMFC SFC) minus durability evaluation (LANL JMFC SFC) minus five-cell stack (SFC)
DOE Kick-off Meeting Washington DC ndash September 28 2010 44
- deg deg
05 M MeOH in 01 M HClO4
PtRuC (commercial)) 10 nmol Pt + 10 nmol Ru
mA
μg Pt
)
4
6
8
55
DMFC Anode Research Activity
bull DMFC Vth=121 V (at 25degC) fuel specific energy 61 kWhkg
bull CH OH + 2H O rarr CO + 6H+ + 6e- E cong 002 V (at 25 C)CH3OH + 2H2O rarr CO2 + 6H+ + 6e Edeg cong 0 02 V (at 25degC)
bull Reduction of methanol-oxidation overpotential through atomic-level control of PtRu nanoparticle synthesis minus optimal Pt atom ensembles for MeOH adsorption and abstraction of H atomsoptimal Pt-atom ensembles for MeOH adsorption and abstraction of H atoms minus adequate Ru coverage for providing OH and O species for CO oxidation minus submonolayer of Pt on Ru nanoparticles through galvanic replacement of Cu adlayers
bull Catalysts on oxide supportsCatalysts on oxide supports (e g(eg NbONbO2 SnOSnO2 MagneacuteliMagneacuteli phases)phases)bull
minus cation-adsorptionreductiongalvanic-displacement method minus significant reduction in Pt loading expected
10
adsorption
Electrochemicalor chemical reductionadsorption
Electrochemicalor chemical reductionadsorption
Electrochemical or chemical reduction
PtRuC (BNL) 033 nmol Pt + 045 nmol Ru
j (m
0
2
4
-04 -02 00 02 04 06 08 10 12C ti d ti d ti l i di l t th d
Immersion in Pt solution
Further Ptdeposition by electrochemical or chemical methodsreplacement
Immersion in Pt solution
Further Pt deposition by electrochemical or chemical methodsreplacementreplacement
Cation-adsorptionreductiongalvanic-displacement method of metal deposition on oxide surfaces EAgAgCl (V)
DOE Kick-off Meeting Washington DC ndash September 28 2010
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
- deg deg
05 M MeOH in 01 M HClO4
PtRuC (commercial)) 10 nmol Pt + 10 nmol Ru
mA
μg Pt
)
4
6
8
55
DMFC Anode Research Activity
bull DMFC Vth=121 V (at 25degC) fuel specific energy 61 kWhkg
bull CH OH + 2H O rarr CO + 6H+ + 6e- E cong 002 V (at 25 C)CH3OH + 2H2O rarr CO2 + 6H+ + 6e Edeg cong 0 02 V (at 25degC)
bull Reduction of methanol-oxidation overpotential through atomic-level control of PtRu nanoparticle synthesis minus optimal Pt atom ensembles for MeOH adsorption and abstraction of H atomsoptimal Pt-atom ensembles for MeOH adsorption and abstraction of H atoms minus adequate Ru coverage for providing OH and O species for CO oxidation minus submonolayer of Pt on Ru nanoparticles through galvanic replacement of Cu adlayers
bull Catalysts on oxide supportsCatalysts on oxide supports (e g(eg NbONbO2 SnOSnO2 MagneacuteliMagneacuteli phases)phases)bull
minus cation-adsorptionreductiongalvanic-displacement method minus significant reduction in Pt loading expected
10
adsorption
Electrochemicalor chemical reductionadsorption
Electrochemicalor chemical reductionadsorption
Electrochemical or chemical reduction
PtRuC (BNL) 033 nmol Pt + 045 nmol Ru
j (m
0
2
4
-04 -02 00 02 04 06 08 10 12C ti d ti d ti l i di l t th d
Immersion in Pt solution
Further Ptdeposition by electrochemical or chemical methodsreplacement
Immersion in Pt solution
Further Pt deposition by electrochemical or chemical methodsreplacementreplacement
Cation-adsorptionreductiongalvanic-displacement method of metal deposition on oxide surfaces EAgAgCl (V)
DOE Kick-off Meeting Washington DC ndash September 28 2010
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
0 00
66
DMFC Anode Research Activity
bull New PtRu catalysts for further thrifting of the Pt content minus new formulations minus different supports minus performance referenced to Johnson Mattheyrsquos HiSPECreg 12100 catalyst
0400
HiSPEC6000 - PtRu Black HiSPEC6000 PtRu Black
HiSPEC12100 - PtRuC
Experimental PdRu
Development PtRu Catalyst
150300
0600
0500
20
25
20
W
g Pt
Potte
ntia
lE v
s R
HE
iR fr
ee
0200
5 0000
0 100 200 300 400 500 600 700
Mass ActivityymAmgg-1 Pt or Pd
Anode polarization plots (iR-corrected) with various 0 Gen 1 Gen 2 Gen 3 Gen 4 Gen 5 JMFCrsquos catalysts (10 M MeOH 80degC) Evolution of JMFCrsquos DMFC MEA
10
0100
DOE Kick-off Meeting Washington DC ndash September 28 2010
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
77
DMFC Anode Research Activity
bull PtSn catalysts minus PtSn catalysts showing lower onset potential for MeOH oxidation than PtRu however
performing below PtRu at high current densities minus model indicating OH formation on PtSn at lower potentials than on PtRu but slow
decrease in CO coverage with potential (PtRu a better catalyst at higher potentials)decrease in CO coverage with potential (PtRu a better catalyst at higher potentials) minus assess scope for exploiting the lower onset potentials of PtSn for methanol oxidation
0 4
05
06
07
0 6
07
08
09
1
erag
e
PtRu OH
01
02
03
04
E V PtRu
PtSn
01
02
03
04
05
06
Frac
tiona
l Cov
e
PtRu CO PtSn OH PtSn CO
0 0 10 20 30 40 50
J mA cm-2
0 0 01 02 03 04 05 06
E V
Anode polarization plots OH and CO coverage modelling
DOE Kick-off Meeting Washington DC ndash September 28 2010
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
88
DMFC Anode Research Innovative Nanostructures
(A) ECSA loss of PtC (E-TEK) Pt black (E-TEK) and PtNT under cycling from 0 to 13 V (vs RHE) at 50 mVs in Ar-purged 05 M H2SO4 at 60degC 50 mVs scans between (B) ORR polarization plots of PtC Pt black PtNT and PdPtNT in O2-saturated 05 M H2SO4 Inset Mass activity and
SEM image of SEM image of supportlesssupportless Pt nanotubes (Pt nanotubes (PtNTPtNT)) specific activity of PtC Pt lack PtNT and PtPdNT catalysts at 0 85 Vspecific activity of PtC Pt lack PtNT and PtPdNT catalysts at 085 V
bull Supportless Pt nanotubes already synthesized bull Pt nanotubes showing improved cycling durability compared to nanoparticle
catalysts and possibly higher activity bull Approach also applicable to the cathode bull Initial focus on PtRu catalysts
DOE Kick-off Meeting Washington DC ndash September 28 2010
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
99
DMFC Anode Research Innovative Nanostructures
bull PtRu nanotubes Complete displacement of Ag with Pt Ruminus Complete displacement of Ag with Pt Ru
minus Displacement reactions PtCl62- (aq) + 4 Ag (s) rarr Pt (s) + 2 Cl- (aq) + 4 AgCl (s) Ru3+ (aq) + 3 Cl- (aq) + 3 Ag (s) rarr Ru (s) + 3 AgCl (s)
Silver NW PtRu NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Synthesis of PtRu nanotubes
bull Metal nanotube substrate minus Inexpensive metal source used as template Inexpensive metal source used as template minus Partial displacement of metal with Pt Ru minus Form PtRu alloy on the entire metal nanotube substrate
Silver NW
Metal Fill
Metal NT
+ PtCl62- (aq)
+ RuCl3 (aq)
Metal Fill PtRu Shell
DOE Kick-off Meeting Washington DC ndash September 28 2010
Synthesis of PtRu nanotubes with the aid of a metal nanotube substrate
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
DMFC Anode Research Durability
bull Limiting Ru crossover as a major cause of DMFC performance loss (mitigation methods to be applied to viable Ru containing anode catalysts developed in the project)methods to be applied to viable Ru-containing anode catalysts developed in the project) minus high temperature cure of anode catalyst minus pre-leach of unstable Ru phase(s) minus use of low permeability membranesuse of low-permeability membranes
minus electrochemical method of limiting ruthenium ndash main focus
09 D
MMFC
Vol
tage
(VV)
Initial After 115 h After 330 h
0 50 100 150 200 250 300 350
08
07
06
0 505
04 02
01
00
Current Density (mAcm2)
Performance of an electrochemically-treated MEA after different times of DMFC operation 80degC
HFR
( Ω c
m2 )
DOE Kick-off Meeting Washington DC ndash September 28 2010 1010
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Alternative Fuels Dimethyl Ether and Ethanol
Dimethyl ether bull DME fDME fuell cellll VVth=11 1515 VV ((at 25t 25degdegC)C) ffuell specifiific energy 8 0 kWhk80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull High fuel vapor pressure (59 atm at 25degC) conducive to passive fuel delivery bull Oxidation kinetics strongly dependent on temperature making DME a more attractive
fuel at high temperatures than methanol bull Research
minus enhancement of DME oxidation through acceleration of the dissociative DME adsorption minus effect of Pt-to-Ru ratio on the rate of DME oxidation to CO2 (from 101 to 13) minus the role of a third metal or non-metallic component (eg SnO2)
gono go decision after Q5minus gono-go decision after Q5
Ethanol bull DEFC Vth=115 V (at 25degC) fuel specific energy 80 kWhkg
bull C2H3OH + 3H2O rarr 2CO2 + 12H+ + 12e- Edeg cong 008 V (at 25degC)
bull Advantages High energy content renewable non-toxic easy to handle and distribute
bull Main challenge Slow incomplete oxidation ndash electrocatalytic scission of the C-C bond very difficult to accomplish at low temperatures
DOE Kick-off Meeting Washington DC ndash September 28 2010 1111
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
1212
Ethanol Oxidation Scheme amp Catalyst Concept
bull On Pt EtOH oxidation is slow and limited to acetaldehyde at existing catalysts ((followingg the α-C-H bond dissociation)) C2H5OH + Pt(H2O) rarr Pt(CH3CHO) + H2O + 2H+ + 2eshy
C-C bond splitting is difficult
bull Ternary PtRhSnO2 model catalyst capable of oxidizing EtOH to CO2 (at 25degC) minus Pt - abstraction and oxidation of H atoms minus SnO2 - source of OH for oxidation of strongly bound intermediates minus Rh - small amounts placed either on SbO2 or Pt to aid in C-C bond scission
PtPtRhSnO2C
Nanoparticles Rh 2ML SnO2 + 12ML Rh 2ML SnO2 + 1ML Pt
Pt(111) Rh(111) SnO2
Model Catalysts Real Catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
- -
1313
Ethanol Improved Synthesis amp Catalyst Composition Optimization
bull A modified polyol method Pt-Rh-SnO nanopaticles H PtCl + RhCl + SnCl + NaOH + EG + H Ominus Pt Rh SnOx nanopaticles H2PtCl6 + RhCl3 + SnCl2+ NaOH + EG + H2O
minus Heat treatment 200ordmC Ar 1 hour
Pt
Rh Heat Treatment
Rh
Sn
SnO2
Pt-Rh-SnPt Rh Sn Pt Rh SnO Pt-Rh-SnOx
bull The effect of catalyst composition ie the PtRhSn ratio
15 08 Pt Rh S 3 1 2PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
Room Temperature Room Temperature 10mVs
04
06 045V vs RHE
PtRhSn = 312 PtRhSn = 313 PtRhSn = 314 PtRhSn = 315 PtRhSn = 316
05M EtOH + 01M HClO4
00
02
Room Temperature
0 10 20 30 40 50 60
-2j
Pt
mA
cmm
ug 10
05 -2
j
Pt
mA
cm
ug
00 01 02 03 04 05 06
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE Time min
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Ethanol Oxidation Performance Ternary Catalyst vs PtC
HR-TEM PtRhSnO2C Room Temperature 60degC
2 525 10P tC ETEK Pt ETEK
20 Pt RhSnO CPtRhSnO C 22 8 05M EtOH + 01M HClO405M EtOH + 01M HClO4
j m
AAc
m-2
E
V v
s R
HE
15 1mVs
E V
vs
RHH
Ej
mAA
cm
-2 1mVs 6
104
05 2
0PtRhSn 314 00 01 02 03 04 05 06 07 01 02 03 04 05 06 07
E V vs RHE E V vs RHE
0606 PtC ETEKPtC Pt RhSnO CPtRhS nO C 20505 2
04
03
04
03
02 02
01 01-4 -3 -2 -1 0 -4 -3 -2 -1 0 1
Log j mA cm-2 Log j mAcm-2
bull ~ 03 V difference observed under voltammetric and steady-state conditions bull At 0 3 V Pt Rh S O C ff i t d f it d t d itAt 03 V Pt-Rh-SnO2C offering a two-order of magnitude current-density
advantage over a standard E-TEKC catalyst
DOE Kick-off Meeting Washington DC ndash September 28 2010 1414
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
1515
Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
-2
Cha
rgge
Q μm
olc
m
Inte
graat
ed B
and
Inte
nnsity
CO22
CH3COOH
010
008
006
004
0 02 002
000
8
4
01
Pt-Rh-SnOxC
E vs RHE
2400 2000 1600 1200
082V 073V 064V 055V 046V 040V 035V 026V
00
Wavenumber cm-1 100
80
60
40
20
bull Product quantity Product quantity Q = A εQ = Ai εeff
Ai - integrated band intensity Εeff - effective absorption coefficient
bull Charge contribution Ci = 100 (nitimesQi) Σ(nitimesQi) 0 04 06 08 10
DOE Kick-off Meeting Washington DC ndash September 28 2010
E V vs RHE CO2 - 6e-molecule CH3COOH - 4e-molecule
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Advanced Membranes for Portable Power Fuel Cells
Issue Objective
Selectivity High proton conductivity but low methanol permeability
Stability Chemicalmechanical stability of DMFCDEFC membranes
MEA processibilityMEA processibility Interfacial stability between membrane and PFSA-bonded electrodesInterfacial stability between membrane and PFSA bonded electrodes
Material Design Options
1616DOE Kick-off Meeting Washington DC ndash September 28 2010
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Relative Selectivity of Various Sulfonated PEMs
Proton conductivity (mScm) 6 20 70 90 100 104 105
15 PFSA Partially fluorinated HC-based (random) F ti lFunctional HC-based (cross-linked)
00 01 02 03 04 05 06 07
δ
12
9
6
18λ
Fraction of conducting volume (FCV)
times R
elat
ivee
Sele
ctiv
ityprop conductivi ty 3FCV =
MVCMVC(wet) y
0MVC ndash molar volume per charge
Fraction of Conducting Volume (FCV)a tion of C t Volu e (F V)Fr c onduc ing m C
Functional Polymer moiety resulting in a specific interaction such as hydrogen bonding dipole-dipole or acid-base interactions Examples carboxylic acid group nitirile amide phosphine oxide imidazole
Kim and Pivovar Ann Rev Chem Biomol Eng 1 23-148 2010 Kim et al manuscript in preparation
DOE Kick-off Meeting Washington DC ndash September 28 2010 1717
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
μ
bull Membrane thickness 50 μm
bull Thickness 30 (supporter) 10 (selectiv la r)
bull Thickness 50 μm including submicron coating layer
Three Approaches to Advanced Membranes
Membrane thickness 50 μm bull Relative selectivity 2‐5 bull Advantage Simple processing bull Major Challenge PEMs with good balance of selectivity
1 Homogeneous thin membrane
(LANL VT) and conductivity
m m e yebull Thickness 30 μm (supporter) 10 μm (selective layer) bull Relative selectivity 5‐10 bull Advantage High selectivity bull Major Challenge Membrane processing
2 Multi‐layer membrane
(LANL) Major Challenge Membrane processing
bull Relative selectivity 2‐5 bull Advantage Good interfacial compatibility amp conductivity Major Challenge S rfa e treatment
3 Surface treated membrane
(VT)
1818DOE Kick-off Meeting Washington DC ndash September 28 2010
bull Major Challenge Surface treatment
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
ob c u b oc c u b oc
‐
PEM Structures for Homogeneous Thin Membranes
Fl i ti F tiFluorination Functionall group Cross-linking agent KO3SCN
OCF3
S O
m
O C O O O
n OCF3
SO3K
Hydyd oprophobic multi-block Hydrophilic multi-blockyd op
Component Role in PEM
Functional group Increasing selectivity
Fluorination Increasing phase separation and conductivity
Cross‐linking agent Increasing selectivityCross linking agent Increasing selectivity
Multi‐block structure Increasing flexibility phase separation and conductivity
DOE Kick-off Meeting Washington DC ndash September 28 2010 1919
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
2020
Polymer Processing for Homogeneous Thin Membranes
Block Copolymer Film (BisSF 17k12k) Random Copolymer Film (6F40)
Membranes with uniform thickness in the range 30-200 microm can be provided by Virginia Tech for MEA fabrication
DOE Kick-off Meeting Washington DC ndash September 28 2010
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
DMFC Performance of MEAs with Homogeneous Thin Membranes
05 M MeOH 20 M MeOH 09 09
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400
HFR
( Ω c
m2 )
Ceel
l pot
entia
l (VV)
m-SPAEEN-60 (53 μm) BPSH-35 (74 μm) Nafion (250 μm)
0 100 200 300 400 500 600
08
07
06
08
07
06
05 05
04 04
03 03
02
01
00
02
01
00
Current density (mAcm2) Current density (mAcm2)
bull PEM performance comparison carried out at a fixed methanol crossover limiting current (50 mAcm2 using 05 M MeOH feed)
bull Performance improvement with hydrocarbon membranes thanks to better selectivitymembranes thanks to better selectivity
Membrane Relative SelectivitySelectivity
M‐SPAEEN‐60 29
BPSH‐35 13
Nafionreg 1
Kim et al J Electrochem Soc 155 B21-B26 2008
Nafionreg 1
DOE Kick-off Meeting Washington DC ndash September 28 2010 2121
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Coating layerProt
Anode catalystlayer
cathode catalystlayer
Protonexchangemembrane
ye
Multi-Layer Membranes
Two-Layer System Three-Layer System
Cathode CathodeAnode Anode g y catalyst la r catalystcatalyst catalyst oncatalyst P t Highly layer catal st Highly Proton HighlyProton Highly catalyst
layerlayer selectiveexchange layer selective exchange selective PEMmembrane PEM membrane PEM
Highly selective
Highly selective
Anode CathodePEM
PEMAnode Cathode PEM
PEM
MeOH concentration
profile
Highly selective PEM layers also improving interfacial compatibility
Kim and Pivovar US Patent Application LANL 2006
DOE Kick-off Meeting Washington DC ndash September 28 2010 2222
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Long-Term Stability of MEAs with Different Membranes
Homogenous Thin Membrane Multilayer Membrane
Cur
reent
den
sity
(Ac
m2 )
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
Cur
r eent
den
sity
(Ac
m2 )
025
020020
015015
010010
025
020200
010155
010100010010 010100
005005 000055
6FCN-35 coated BPSH-35
02
01
00 HFFR
(Ohm
cm
2 )
0 250 500 750 1000 1250 1500 1750 2000 0 250 500 750 1000 1250 1500 1750 2000
Time (hour) Time (hour)
Nafionreg 1135 Control PEM Restart test Restart test
025 bull DMFC test conditions 05 V 80degC (a)020 05 M MeOH ambient pressure 015
unrecoverable lossloss No indication of PEM or interface degradationbullbull No indication of PEM or interface degradation010 recoverable loss
Cur
rent
dens
ity (A
cm
2 )
005
02
01
00 0 100 200 300 400 500 600 700
Time (hour)
HFRR
(Ohm
cm2 ) bull Both membrane systems showing superior
performance to the Nafionreg reference system
Kim et al J Electrochem Soc 157 B1602-B1607 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 2323
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
2424
Basic Concepts of Membrane Post-Fluorination
bull No modification Possible poor compatibility with Nafionreg in electrodes No modification Possible poor compatibility with Nafion in electrodes SO3H
OO
OS OOS O 64 O OO O
H3OS
bull Fluorination Phase separation and improved interface with Nafionreg in electrodes
F2 F2
F2
F2
SO3H F F F F O O
OS OOS O 64 O
H OS FF FF FF FF FF FF FF O
H3OS
DOE Kick-off Meeting Washington DC ndash September 28 2010
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
2525
Post-Fluorination of BPSH-40 Membrane
50 nm 50 nm
(a) (b) Tapping mode AFM
(a) SPAES (BPSH 40 control)(a) SPAES (BPSH-40 control) (b) FSPAES ndash 10 minutes (c) FSPAES ndash 30 minutes (d) FSPAES ndash 60 minutes
Relative humidity ~ 35
(c)
50 nm
(d)
50 nm
bull Fluorination developing morphological order on ththe surfface of BPSH-40f BPSH 40 membrane
bull Preliminary data indicating improved DMFC MEA improved DMFC MEA performance at higher current densities
DOE Kick-off Meeting Washington DC ndash September 28 2010
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Fuel Cell Testing amp Multi-Cell Device
bull Single-cell testing of materials including life-testing for up to 2000 hours (LANL JMFC)
bull Integration of selected materials into 50 cm2
MEA f th fi ll t k (JMFC)MEAs for the five-cell stack (JMFC) bull Integration of MEAs into the stack and stack
testing (SFC Energy) bull Deliverablesbull Deliverables forfor thethe DepartmentDepartment ofof EnergyEnergy
completed by Q16
000777000 141414
707070degC 03degC 03degC 03 MMM CHCHCH 333OHOHOH
erererA
vA
vA
vaaaggg
eee C
elC
elC
ellll V
olVo
lVo
ltttagagag
e (
e (
e (VVV
))) 000666555 121212121212
101010 000666000 26x26x26x
000555555
23x23x23x 20x20x20x 175175175xxx 666
888
000555000 444
000444555 222
000444000 000 000000000 000050505 000111000 000151515 000202020 000222555
CurrenCurrenCurrenttt DenDenDen sssititity (Ay (Ay (A cmcmcm-2-2-2)))
StStStacacac
kkkkkk P PP
ooowwweeerrr
P PPrrro
dododuc
tion
uctio
nuc
tion
(((WWW))))))
Short-stack DMFC stack hardware developed at LANL for militilitary power applilicatitions
DOE Kick-off Meeting Washington DC ndash September 28 2010 2626
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
t t
-
Tasks amp Schedule
bull Task 1 DMFC Anode Research minus 11 Catalysts with Improved Activity and Reduced Cost minus 1 2 A C D bilit12 Anodde Catallyst Durability
bull Task 2 Alternative fuels for portable fuel cells minus 21 Ethanol Oxidation Electrocatalysis minus 22 Dimethyl Ether Research
bullbull Task 3 1Task 31 Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes)Innovative Electrode Structures for Better Activity and Durability (Metal Nanotubes) bull Task 4 Hydrocarbon Membranes for Lower MEA Cost and Enhanced Fuel Cell Performance
minus Block Copolymer Synthesis minus Copolymers with Cross-linkable End-groups
bullbull Task 5Task 5 Characterization performance and durability testing multi-cell deviceCharacterization performance and durability testing multi cell device minus Fuel Cell Testing Performance amp Durability minus Multi-cell Device(Five-Cell Stack)
Task Schedule by Quarters with Milestones (M) and Decision Points (G)
TASK QUARTER
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 11 MM MG MM MG M MG MMM
12 MMG M M
21 MM MMG M M M G M MMG MMM MMG M M M G M MMG M
22 M MG MG
31 MMG MG MMG MG MG MG M
41-42 MMG M MMG M MMG MMG
51 MMMM
52 MM M
Periods after a high-risk gono-go decisions are shown in a lighter shade
DOE Kick-off Meeting Washington DC ndash September 28 2010 2727
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
- - -
Approach FY11 Milestones
Date Milestone
Mar 11 Complete evaluation of at least three PtRu catalysts of different compposition for DME oxidation
Apr 11 Conclude synthesis of trisulfonated hydrophilic (SQS) 6F copolymers
Apr 11 Demonstrate a nanotube catalyst with MeOH oxidation activity within 0 05 V of the state-of-the-art PtRu catalysts005 V of the state of the art PtRu catalysts
June 11 Complete equipment set-up for stack evaluation adapt stack hardware to testing hydrocarbon membranes of different thickness
S 11Sep 11 D t t M OH id ti t l t th t i ifi tl dDemonstrate a new MeOH oxidation catalyst that significantly exceeds half-cell mass activity of 200 mAmgPt at 035 V at 80degC (iR-corrected)
Sep 11 Improve the ternary PtRhSnO2 electrocatalyst to oxidize EtOH to CO2 with an efficiency of 50 at the anode potential of 04 V and 80degC
DOE Kick-off Meeting Washington DC ndash September 28 2010 2828
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Summary
bull This is a multi-partner and multi-task project targeting substantial improvements to the performance of portable fuel cells with a liquid fuel feed to the anodethe performance of portable fuel cells with a liquid fuel feed to the anode
bull The key technical objective for the direct methanol fuel cell (DMFC) is to assure sustained operation at a cell voltage of 06-07 V (depending on specific application and cost requirements)
bull The focus of the DMFC research is on (i) enhancement of the anode catalyst activity through novel catalyst composition and structure (ii) increase in the membrane selectivity (iii) improvement to the MEA stability including that of the membrane-electrode interface and the catalyst itself and (iv) reduction in the cathode loss caused by migration of unstable anode components (eg Ru crossover)
bull Electrocatalysis of dimethyl ether oxidation is studied in the context of a system with ldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFCldquopassiverdquo fuel supply DME anode performance will be referenced to that of a DMFC anode operating under similar conditions
bull Ethanol research concentrates on the development of mostly ternary oxidation catalysts capable of breaking the C-C bond in the C2H5OH molecule and assuringcatalysts capable of breaking the C C bond in the C2H5OH molecule and assuring high CO2 yields
bull Potentially viable materials developed in the project will be tested for long-term stabilityy in a singgle fuel cell and if jjudgged ppractical incor pporated into a short fuel cell stack
DOE Kick-off Meeting Washington DC ndash September 28 2010 2929
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Title
3030DOE Kick-off Meeting Washington DC September 28 2010
Supplemental Slides
ndash
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Interfacial Stability Poor wetting-adhesion water uptake of cathode
water uptake of anodeMEA 6060
50
proton conducting chhannell
HFFR
gai
n (m
Ω c
mm2 ) 40
30
20
10
Water transport mismatch MEMEMEAAA MEMEAA
HH22OO HH OOHH22OO
0 Sulfonated poly(arylene ether)
-10
-20
Nafionreg
Recast Nafionreg
0 20 40 60 80 100 120 140 hihighgh dd rraagg polpolyymmeerr llooww dd rraagg popollyymmeerr
Water uptake (vol )Dimensional mismatch
Dry state
Water uptake lower than 40 vol assuring good stability of the membraneelectrode interface
mechanical stress at th l dthe electtrodeshymembrane interface may lead to delaminationHydrated state
Kim and Pivovar J Electrochem Soc 157 B1616-B1623 (2010)
DOE Kick-off Meeting Washington DC ndash September 28 2010 3131
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
t
λ
onc
P l A hit t
Effect of Chemistry on Membrane Properties
FCV=035
SO H C λ Relative Rel MeOH Polymer Chemistry SO3H Conc (mgramequivcm3)
λ (H2OSO3H)
Relative Conductivity
Rel MeOH Permeability
PFSA 18 165 (18) 085 (018) 096 (006)
P tiPartialllly flfluoriinatedd 19 157 (18) 087 (023) 069 (017)
HC-based 23 141 (25) 086 (024) 038 (013)
Functional 2 5 12 4 (3 1) 0 83 (0 33) 0 24 (0 12)25 124 (31) 083 (033) 024 (012)
FCV=025
SO3H Conc λ Relative Rel MeOH Polymer Architecture 3 (mgramequivcm3) (H2OSO3H) Conductivity Permeability
Random copolymer 16 120 (19) 046 (02) 019 (008)
H l 2 2 87 (15) 0 39 (0 1) 018 (005)Homopolymer 22 8 7 (1 5) 039 (01) 0 18 (0 05)
Cross-linked copolymer 31 56 (17) 066 (02) 010 (004)
Standard deviation given in parenthesisStandard deviation given in parenthesis
DOE Kick-off Meeting Washington DC ndash September 28 2010 3232
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-
Acknowledgments
bull DOE-EERE Fuel Cell Technologies Program
bull T hTechnollogy DDevellopmentt MManager DDr NNancy GGarllandd
DOE Kick-off Meeting Washington DC ndash September 28 2010 3333
- Advanced Materials and Concepts for Portable Power Fuel Cells
-
- Overview
- Relevance Objective amp Targets
- Approach Focus Areas
- DMFC Anode Research Activity
- DMFC Anode Research Innovative Nanostructures
- DMFC Anode Research Durability
- Alternative Fuels Dimethyl Ether and Ethanol
- Ethanol Oxidation Scheme amp Catalyst Concept
- Ethanol Improved Synthesis amp Catalyst Composition Optimization
- Ethanol Oxidation Performance Ternary Catalyst vs PtC
- Ethanol Oxidation In situ IRRAS Quantification of Reaction Products
- Advanced Membranes for Portable Power Fuel Cells
- Relative Selectivity of Various Sulfonated PEMs
- Three Approaches to Advanced Membranes
- PEM Structures for Homogeneous Thin Membranes
- Polymer Processing for Homogeneous Thin Membranes
- DMFC Performance of MEAs with Homogeneous Thin Membranes
- Multi-Layer Membranes
- Long-Term Stability of MEAs with Different Membranes
- Basic Concepts of Membrane Post-Fluorination
- Post-Fluorination of BPSH-40 Membrane
- Fuel Cell Testing amp Multi-Cell Device
- Tasks amp Schedule
- Approach FY11 Milestones
- Summary
- Supplemental Slides
-
- Interfacial Stability
- Effect of Chemistry on Membrane Properties
- Acknowledgments
-