Pt-Free Membrane Fuel Cells

Latest progress on

Alkaline Membrane Fuel Cells (AMFCs)

Dario R. Dekel; dario@cellera.biz +1 (828) 348 4444; +972 (54) 252 6370

Breaking the Fuel Cell Cost Barrier

CellEra CONFIDENTIAL

10th Israeli Advanced Power Sources Conference – Tel Aviv

2

What is an AMFC ?

From “Alkaline membrane fuel cells”; Dario Dekel, In: Savinell R, Ota K, Kreysa G

(eds) Encyclopedia of applied electrochemistry: Springer reference (www.springer-

reference.com). Springer

Enhanced electrokinetics of

the ORR, allowing for the use

non-Pt catalysts

Extended range of

(available) stack materials

Wider choice of fuels in

addition to H2

AMFC stack structure

Replace acidic solid electrolyte with an alkaline solid electrolyte

3 From www.cellera-inc.com

4

*From “Alkaline Membrane Fuel Cells: Membranes”. Dario R. Dekel;

In: Savinell R., Ota K., Kreysa G. (Ed.) Encyclopedia of Applied Electrochemistry:

SpringerReference (www.springerreference.com) (2013)

Schematic diagram showing OH- conductivity mechanism*

Anion conductive polymer: core component

AMFC worldwide - Academy

In 2013 more than 200 papers focused on AEMs, electrocatalysts, and also on small lab scale AMFC preparation and testing were published. Leading academic groups in PennState, Surrey, Wuhan, NREL (etc…) are making interesting progress:

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Hickner (Tew et al., JACS 2012) works on fundamental

development of new anion conducting polymers for

AEMs. Some first polymers already showed practical

conductivity, but poor stability (hours-level).

Varcoe (AMFC workshop, Surrey 2013) keep making

progress using a simple radiation-grafted process to

functionalize commercially available films. Initial

reasonable IECs were already obtained in their ETFE-

based membranes.

Best power density result published for a complete non-Pt cell: 70mW/cm2

Tang DaoPing, et al.; Sci. China Chem. 2 (2010) 53

Best published result in Pt-free-based AMFC technology: Max. power density of 70mW/cm2

AMFC worldwide - Academy

State-of-The-Art in AMFCs

CellEra is defining THE state-of-the-art in AMFC technology

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CONFIDENTIAL

CellEra’s crosslinked AMFC, non-Pt cathode,

dry H2 / filtered air, 60C

CellEra’s results based on

non-Pt anode / non-Pt cathode

CellEra’s state-of-the-art in AMFCs is worldwide recognized by all academic and commercial groups working in this technology. Therefore, CellEra is the leader player in the most important collaborative works being carried out in AMFCs

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CONFIDENTIAL

State-of-The-Art in AMFCs

A Novel Method for Making a Robust AMFC

Rise of HFR with time in old and new CellEra’s cells

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--- Pre polymer modification

--- After polymer modification

CONFIDENTIAL

CellEra developed a new polymer modification approach that stabilizes the functional

groups of the polymer reducing the cell resistance degradation

Full-sized short stack cycling – progress over

time

Improvement in cycle-ability in 6-cell short stacks over time

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CONFIDENTIAL

Initial performance/voltage efficiency of full-sized 6-cell short stacks was improved

by 50% over the last 2 years

Average initial cell voltage of full-sized

short stacks throughout past years

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CONFIDENTIAL

CellEra’s AMFC voltage efficiency – progress over

time

0

100

200

300

400

500

600

0 0.4 0.8 1.2 1.6 2

mW

/cm

2

A/cm2

Y2011 Y2012

5cm2 cells

Pt Anodes Pt Anodes

Ni decorated catalyst

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.4 0.8 1.2 1.6 2

V

A/cm2

Y2013

Ni-decorated Anodes**

Non-Pt cathode catalyst Dry H2 / 3barg Filtered air / 1barg

70C

Electrocatalyst development – status and progress

over time

Pt 1 mg/cm2

** CellEra’s patent PCT/US2013/039853

WO/2013/184269

CONFIDENTIAL

Full size AMFC stack design

• Temperature distribution along the cells is now homogeneous within a very small

variation (±1°C). As a consequence of the good thermal as well as gas flow

homogeneity achieved, voltage distribution along the stack is low (StdDev <20 mV),

proving stack design is optimum.

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CONFIDENTIAL

10 20 30 40 50 605354555657585960616263

Cell # [ ] (from An to Ca, i.e., from gases outlets to inlets)

Te

mp

era

ture

[C

]

58 A (cycle 3): Cell Ca Center[h]

58 A (cycle 3): Cell Ca mid-height; Cold side across cooling channel[h]

58 A (cycle 3): Cell Ca mid-height; Hot side across cooling channel[h]

2h zoom-in on a 12h long ON cycle, Dec 4th 2013

CONFIDENTIAL

840.2 840.4 840.6 840.8 841 841.2 841.4 841.6 841.8 8420

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0.8Test #2892 ; 58 cell(s) ; 235 cm

2 @ AMR4/KIKU1i [/KIKU13i old version w Keithley]

time [h]

Ind

ivid

ual

Cell

Vo

ltag

e [

V]

Full size AMFC stack design

Voltage stability/distribution during long ‘ON’ cycles

Ammonia as a fuel source

• We have initiated testing of our stacks using a fuel mix which simulates the

expected output of the ammonia cracker, using a diluted 75% H2, 25% N2 fuel mix.

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3 4 5 6 70

15

30

45

60

75

90105

120

135

150

165

180

195210

225

240

255

270

285

time [h]

Pow

er [W

] ; I

[A]

Test #2828 ; 6 cell(s) ; 235 cm2 @ KIKU 2-19

3 4 5 6 700.1

0.2

0.3

0.4

0.5

0.60.7

0.8

0.9

1

1.1

1.2

1.31.4

1.5

1.6

1.7

1.8

1.9

Volta

ge/C

ell (

avg)

; Te

mp/

100

[C

]; H

FR [m

/c

ell];

MFC

s/10

0 [s

LPM

]

Power

Current

Voltage

Stack Temperature

HFR

H2/N

2 75/25

mix

pure

H2

CONFIDENTIAL

NH3 75%H2

First results are promising,

achieving 90% of the power density

achievable with neat hydrogen. This

is prior to any optimization in cell

and stack design

** CellEra’s patent US2012/0043519

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CellEra’s team @2013

Dario R. Dekel

+1 (828) 348 4444

+972 (54) 252 6370

dario@cellera.biz