ADVANCED BATTERIES FOR AUTOMOTIVE APPLICATIONS

ADVANCED BATTERIES

FOR AUTOMOTIVE

APPLICATIONS

Donald R. Sadoway

Department of Materials Science & Engineering

Massachusetts Institute of TechnologyCambridge, Massachusetts

GCEP Advanced Transportation Workshop October 11, 2005Sadoway

motivation

Imagine driving this:


motivation (continued)

without the need for this:


relevant enabling technology


The message

The road to autonomy is paved

with advanced materials.


specific energies of battery chemistries

(Wh/kg) (MJ/kg)

lead acid 35 0.13NiCd 45 0.16NaS 80 0.28NiMH 90 0.32Li ion 150150 0.540.54

gasoline 12,00012,000 4343


battery performance metrics



RagonePlot


Sadoway’s Rule

1 Wh/kg storage capacity

1 mile driving range


USABC long-term performance goals

operating temp. -40 to 85ºC

specific energy 200 Wh/kg @ C/3

energy density 300 Wh/L @ C/3specific power 400 W/kg

power density 600 W/Lcycle life 1000 cycles @ 80% DOD

service life 10 yearsultimate price ~ $100/kWh for 40 kWh packs


Strong Opinions

Li SPB is the only technology capable of exceeding 200 Wh/kg

Li SPB is unique for its mechanical flexibility

new designs

Li SPB is the only technology capable of meeting safety specs

The Periodic Table of the Elements


some relevant electrochemistry

Look at the inner workings of a lithium battery:

at the anode (-)

Li Li+ + e-

at the cathode (+)

Li+ + e- + LiXCoO2 Li1+XCoO2

Li+ + e- + Co4+ Li+ + Co3+


technical obstacles

anodesafetycycle lifecapacity

e- e-

currentcollector

(Cu)

Li metal

LiXC

SnOX / Sn Li+

loadLiMOx carbon polymer

currentcollector

(Al)

electrolyteelectrical conductivityelectrochemical stability

cathodecapacity power cycle life

_ +

polymer

Li Li+ + e-

Li+ + e- + LiXCoO2 Li1+XCoO2

Li+ + e- + Co4+ Li+ + Co3+


the polymer electrolyte dilemma

electrical properties of a liquid

mechanical properties of a solid

molten/plasticized polymers

crystallized/crosslinked polymers

liquid flow

low conductivity


block copolymer electrolytes

both components liquid low Tg

components mutually immiscible

Li+ solubility in (PEO)8 brushes

liquid-liquid immiscibility + covalent bonding

spatially constrained phase separation (nanoscale)

mechanical stability

secondary block (dimensional stability)

PEO-based block (ion-conduction)

add Li+ as LiCF3SO3


PLUS:facile processingengineered nanostructures

block copolymer electrolytes

T > TODT, disordered

liquid-like

Li+Li+

Li+

solid-like

Li+

Li+

Li+

Li+

T < TODT, ordered

10 - 100 nm

secondary block (dimensional stability)

PEO-based block (ion-conduction)

locally a liquid globally a solid

add Li+ as LiCF3SO3


1st-generation BCEs

C

H

C

3CH

H C

O

O

3CH)( 8

( )x

2CH

C

H

C

3CH

H

CH

C

O

O

3CH)n

( )y

( 2O

POEM PLMA, PnBMA, or PMMA

CH2

poly (oxyethylene methacrylate) poly (alkyl methacrylate)


1st-generation BCEs

C

H

C

3CH

H C

O

O

3CH)( 8

( )x

2CH

C

H

C

3CH

H

CH

C

O

O

3CH)n

( )y

( 2O

POEM PLMA, PnBMA, or PMMA

Tg ~ -60°C-35°C, (n = 11)

Tg ~ 40°C, (n = 3)100°C, (n = 0)

dope with lithium triflate, [EO]:LiCF3SO3 = 20:1.

CH2

poly (oxyethylene methacrylate) poly (alkyl methacrylate)


synthesis of polymer electrolyte


charge/discharge testing


0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2000 4000 6000 8000 10000

volta

ge (V

)

rate = C/2 room temperature

100% solid-state!

charge/discharge testing

capacity (mAh/g)

Li ⏐ Li+ ⏐ VOx


Scalable Synthesis Routes: graft copolymer electrolytes (GCEs)

Tg ~ -60ºC

Tg ~ -120ºC

POEM

poly (dimethyl siloxane)

PDMS

Free Radical Synthesis- macromonomer route - scalable & cheap- no catalysts, no impurities

Graft Architecture- improved mech. properties

High MW PDMS macromonomers- low Tg: high conductivity- microphase separation:

rubbery solid- silicone component:

good T stability


POEM-g-PDMS

σ > 1×10−5 S/cm

conductivity comparable to that of pure POEM liquid microphase separation confers

good mechanical properties

cond

uctiv

ity (S

/cm

)

1.00E-06

1.00E-05

1.00E-04

1.00E-03

2.7 2.9 3.1 3.3 3.5

1000/T

97ºC 25ºC

POEM liquid

POEM-g-PDMS 70:30 solid


TEM of POEM-g-PDMS


thermal stability of POEM-g-PDMS

thermally stable up to 300°C facilitating battery integration, e.g., soldering & sputtering operations

Steven Dallek, NSWC Carderock


GCE stable beyond 5 V

GCE

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 1 2 3 4 5 6

voltage vs Li⏐Li+ (V)

curr

ent (μA

/cm

2 )

22ºC

GCE + LiCF3SO3

voltage vs Li⏐Li+ (V)

22ºC


cycling behavior of GCE thin-film cell

1.5 - 4.0 V, ic = id = C/2, room temperature

Li / GCE (2μm) / VOx

limited by Li surface roughness (~ 1 μm)

0

50

100

150

200

250

0 50 100 150 200 250

cycle number

capa

city

(mA

h/g)

100% solid-state


synthesis of fully-dense cathode films

no binderno additive

100% loading


phase transformation and valuesGITTD~

D varies by almost 100× over range of operation!


AC cyclic voltammetry

(V)

Quantitative assessment of α and ko


1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E-14 1.E-13 1.E-12 1.E-11 1.E-10 1.E-09

D (cm2/s)

Dam

kohl

er N

umbe

r .

diffusion-controlled

reaction-controlled

k = 10-7 cm/s

Damköhler number, Dk = (k L) / D


breaking the one-electron barrier

Today LiCoO2, LiNiO2, LiFe(PO4) all use only one electron per metal (e.g. Co4+/Co3+)

theoretical capacity limited << 300 mAh/g

The Future compounds where metal cycles over multiple redox steps



In the presence of Mn,

Li+ + 2e- + LiXNiO2 Li1+XNiO2

Li+ + 2e- + Ni4+ Li+ + Ni2+

cathode:

Pb4+ + 2 e− Pb2+ (redn)anode:

Pb0 Pb2+ + 2e− (oxidn)



theoretical capacity

≈ 600 mAh/g !

≈ 540 Wh/kg !

two-electron change around Ni upon Li intercalation

In the presence of Mn,

Li+ + 2e- + LiXNiO2 Li1+XNiO2

Li+ + 2e- + Ni4+ Li+ + Ni2+

G. Ceder, MIT



theoretical capacity ≈ 1000 mAh/g !

≈ 700 Wh/kg !

Li+ + 3e- + LiXCrO3 Li1+XCrO3

Li+ + 3e- + Cr6+ Li+ + Cr3+

Your wildest dream


thin-film batteries: fully-dense cathodes

multilayer, flexible laminate

fully dense oxide cathode (0.5 µm)

solid polymer electrolyte (1.0 µm)

metallic lithium anode (0.37 µm)

400 Wh/kg (700 Wh/L) & 650 W/kg (1.1 kW/L)

thin-film battery

fully dense oxide cathode solid polymer electrolyte

metallic lithium anode



x MIT SPB

RagonePlot


So where are we?

not ready for electrification just yet


Learning to crawl before walking

flexible solar cell

flexible battery

flexible necktie


Here is another prototype sLimcell

The Thin ManThe Thin Man™™


It’s a tough way to make a living

application price point

communications $1,000 / kWh

automobile traction $100 - 200 / kWh

laptop computer $5,000 - $10,000 / kWh

severity of service conditions price


Prediction is very difficult, especially about the future.

- Niels Bohr

What can we expect?


observations & opinions

One size does not fit all: different applications call for different power sources tailored designs

Batteries have been around for a long time:user community justifiably frustrated at state of battery development and rate of progress

Big changes are under way:ingress of materials scientists invigorating the field

computational materials science acceleratingthe rate of discovery – knowledge limited


acknowledgments

Office of Naval ResearchOffice of Naval Research

MIT MRSEC (NSF)MIT MRSEC (NSF)

GerbrandGerbrand CederCeder, Anne M. Mayes,, Anne M. Mayes,P.E. P.E. TrapaTrapa, E.A. Olivetti, and S.C. , E.A. Olivetti, and S.C. MuiMui

ADVANCED BATTERIES FOR AUTOMOTIVE APPLICATIONS

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