search for stable electrolytes for lithium-oxygen batteries · 2013-03-19 · search for stable...

TOYOTA MOTOR EUROPE – AT1 division

SEARCH FOR STABLE ELECTROLYTES FOR SEARCH FOR STABLE ELECTROLYTES FOR LITHIUMLITHIUM--OXYGEN BATTERIESOXYGEN BATTERIES

Fanny BardéToyota Motor Europe Toyota Motor Europe ‐‐ Advanced Technology 1 (BE) Advanced Technology 1 (BE)

School of Chemistry School of Chemistry ‐‐ University of St Andrews (UK) University of St Andrews (UK) KU Leuven KU Leuven ‐‐ University of Leuven (BE)University of Leuven (BE)

IBA conference 2013 @ BarcelonaIBA conference 2013 @ Barcelona 1313thth March 2013March 2013


““Environmental friendly portable carsEnvironmental friendly portable cars”” 22


Schemes to support Schemes to support ““last milelast mile”” transportation using small EVtransportation using small EV

http://www.toyota-global.com/innovation/intelligent_transport_systems/hamo/

The driving range of the Ha:mo vehicles is limiteddue to small energy density of lead-acid batteries.

The driving range of the The driving range of the Ha:moHa:mo vehiclesvehicles is limitedis limiteddue to small energy density of leaddue to small energy density of lead--acid batteries.acid batteries.

++

Japan Japan ‐‐Toyota City Toyota City ‐‐ Ha:moHa:mo(Harmonious Mobility Network)(Harmonious Mobility Network)

Grenoble Grenoble ‐‐ Launch of ultraLaunch of ultra‐‐compact urban compact urban EV carEV car‐‐sharing project (end 2014) sharing project (end 2014)

http://media.toyota.ca/pr/tci/en/city-of-grenoble-grenoble-alpes-243923.aspx

33


New EV: New EV: ““eQeQ””

The driving range remains limited (100 km).Batteries with higher energy density are needed.

The driving range remains limited (100 km).The driving range remains limited (100 km).Batteries with higher energy density are needed.Batteries with higher energy density are needed.

44


OutlineOutline

1.1. Research background & Challenges of LiResearch background & Challenges of Li‐‐Air batteryAir battery

2.2. Carbonates as electrolyteCarbonates as electrolyte

3.3. Linear or cyclic ethers as electrolyteLinear or cyclic ethers as electrolyte

4.4. Amides as electrolytesAmides as electrolytes

5.5. Other class of electrolytes for LiOther class of electrolytes for Li‐‐O2?O2?

6.6. Conclusions & Future perspectivesConclusions & Future perspectives

55


LiLi--Air batteries with Li metal and OAir batteries with Li metal and O2 2 gas are highly promising gas are highly promising in view to achieve long cruising range of EV/PHV vehicles.in view to achieve long cruising range of EV/PHV vehicles.

Ragone plotRagone plot ‐‐ Performance of batteries Performance of batteries ‐‐

Long cruising rangeLong cruising range

66Acceleration

Acceleration


Theoretical battery performancesTheoretical battery performances

Battery Potential/ V Specific Energy/ Wh kg-1

Li-ion (Today) 3.8 387

Li/S: 2Li + S Li2S 2.2 2567

Li/O2 (non-aqueous): 2Li + O2 Li2O2 3.0 3505

Li/air (aqueous): 2Li + ½O2 + H2O 2LiOH 3.2 3582

Zn/air: Zn + ½O2 ZnO 1.65 1086

Theoretically, nonTheoretically, non--aqueous Liaqueous Li--air battery could increase drastically the air battery could increase drastically the electric range. But this technology is immature!electric range. But this technology is immature!

Differences between “Li-ion” & “Li-Air”

Batteries?

x10

77


LiLi‐‐Air battery challengesAir battery challenges

Selective membrane not availableShall allow only O2 to enter (while blocking H2O & CO2)

Inherent problems of Li anode- Dendrites formation - Require stable Solid Electrolyte

Interface - Safety issue

Cathode optimization necessary - Design Porous Cathode- Pore size, distribution- Catalyst: type, loading…- Carbon???

Electrolyte requirements- Stability window- High conductivity- Low volatility- High O2 solubility, diffusivity- Compatible with Li

Ideal reaction

2 Li + x O2 Li2Ox

88


Initial LiInitial Li‐‐O2 battery performancesO2 battery performances

Huge hysteresis/Poor rate

REDUCE

RECHARGEABILITY

NEEDED

Discharge: 2 Li + x O2 Li2Ox

Charge : Li2Ox 2 Li + x O2

?PXRD,

NMR, FTIR, Raman...

In situ DEMS (gas

analysis)

discharge

charge

OUR APPROACH:

Capacity fading/ Poor cycle life

CYCLABILITY

NEEDED

To overcome those issues, it is important to understand the To overcome those issues, it is important to understand the fundamental reactionsfundamental reactions mechanism in the battery.mechanism in the battery.

99


OutlineOutline







1010


Propylene Carbonate

The ideal reaction (LiThe ideal reaction (Li22OO22 formation and decomposition) only formation and decomposition) only accounts for accounts for ~~2%. 2%. BUT: How can it cycle?BUT: How can it cycle?

Gas analysis during 1st charge

Li2O2 represents only ~2% of the discharge products

~98% discharged products are issued from PC decomposition by O2 species

FT-IR analysis after 1st discharge

1800 1500 1200 900 600 300

Abso

rban

ce a

.u.

Wavenumber/ cm-1

Li2CO3

Li2O2

υ C=Oυ C-O

υ C-O-Cδ C-H

δ CO2

υ Li-O

= Li2CO3

Carbon/Kynar/Catalyst

Li2CO3 is the main discharge productNo clear evidence of Li2O2 after

discharge2 Li + x O2 Li2Ox

Carbonates as electrolyte: 1Carbonates as electrolyte: 1stst cyclecycle 1111


Li carbonate, Li formate, Li acetate and Li propyl dicarbonate are the main reaction products (instead of Li2O2).

They accumulate in discharge and cause capacity fading.

Cycling is due to the formation (in discharge) & decomposition (Cycling is due to the formation (in discharge) & decomposition (in in charge) of side reactions products resulting from PC decompositicharge) of side reactions products resulting from PC decomposition.on.

It is possible to charge/oxidize these side reaction products around 3.5-4V.

Simultaneous CO2 evolution.

Mole of CO2 evolved per Mole of model reaction product on charging

Gas analysis during charging of model reaction products

Li formate

Li acetate

Li carbonate

FTIR analysis during cycling

Carbonates as electrolyte: CyclingCarbonates as electrolyte: Cycling 1212


Main discharge products are: Li carbonate, LPDC, Li formate and Li acetate

O

OO

O O(2)O O

O

OO

-

- Li+

2

(3)

OLiO

O

O

e-

Li+CO2

oxidative decompositionreactionsO2

OLi

O

OLi

OH2O CO2

(5)

3

Li+

O O

O

1

(4)

O

O

LiO O OLi

O

4

O2- - 1/2 O2

Lithium Propyl Di-Carbonate(LPDC)

Li formate and Li acetate

Li carbonate

[1] Freunberger et al. J. Am. Chem. Soc., 133 (20), 8040–8047, (2011)[2] Z. Peng et al., Angew. Chem. Int. Ed. , Vol 123, 28, 6475–6479, (2011)

PC is unstable and not a suitable electrolyte for LiPC is unstable and not a suitable electrolyte for Li--Air battery.Air battery.Ideal reaction (LiIdeal reaction (Li22OO22 formation) only accounts for formation) only accounts for ~~2%. 2%.

Discharge mechanism: PC decompositionDischarge mechanism: PC decomposition 1313


OutlineOutline







1414


Li2O2evident

BUT

In both linear and cyclic ethers : we observe theIn both linear and cyclic ethers : we observe theLiLi22OO22 formation & electrolyte decomposition on 1formation & electrolyte decomposition on 1stst dischargedischarge

Cyclic(1,3 dioxolane)

Linear(tetraglyme)

CH3-O-(CH2CH2O)4-CH3

30 40 50 60

Li2O2

2θ CuKa/o

1st

discharge

30 40 50 602θ CuKα/o

Li2O2

1st

discharge

1800 1500 1200 900 600 300

Abs

orba

nce

a.u.

Wavenumber/ cm-1

Li2O2

υC=OδC-H

δCO2

υC-O

υLi-O

1st

discharge

1800 1500 1200 900 600 300Wavenumber/ cm-1

Abs

orba

nce

a.u.

δC-H

υC=OυLi-O

δCO2

υC-O

Li2O2

1st

discharge

PXRD

FTIR Side reaction

products also present!

Ethers as electrolyte: 1Ethers as electrolyte: 1stst dischargedischarge 1515


Fadingobserved

No evidenceof Li2O2

1 2 3 4 5500

1000

1500

2000

2500

Cap

acity

/ mA

h g-1

car

bon

Cycle number1 2 3 4 5

500

750

1000

1250

Cap

acity

/ mA

h g-1

car

bon

Cycle number

Extensive electrolyte

decomposition on cycling

30 40 50 60 2θ CuKα/o

5th discharge

Li2O2

30 40 50 60

5th discharge

Li2O2

2θ CuKα/o

Linear (tetraglyme)

1800 1500 1200 900 600 300Wavenumber/ cm-1

5th discharge

5th discharge

1800 1500 1200 900 600 300Wavenumber/ cm-1

5th discharge

Cyclic (1,3 dioxolane)

PXRD

Cycle life

FTIR

After 5 cycles, ethers decomposition is the main reactionAfter 5 cycles, ethers decomposition is the main reaction. .

Ethers as electrolyte: after 5 cyclesEthers as electrolyte: after 5 cycles 1616


[3] Freunberger et al., Angew. Chem. Int. Ed., 50, 1-6, (2011)

• Large improvement when PC replaced by Tetraglyme, but still decomposition is the main reactions after 5 cycles

• Other linear and cyclic ethers were tested and do not present better performances than tetraglyme or 1,3-dioxolane.

Linear or cyclic ethers are not suitable electrolytes for LiLinear or cyclic ethers are not suitable electrolytes for Li--Air batteries. Air batteries.

‐ Diglyme

‐ Triglyme

‐ Tetraglyme

‐ 1,3‐Dioxolane

‐ 2‐Methyl THFO CH3

H3CO

OCH3

2

H3CO

OCH3

3

H3CO

OCH3

4

Ethers as electrolyte: summaryEthers as electrolyte: summary 1717

FOR PRACTICAL APPLICATIONS


OutlineOutline







1818


H

O

NCH3

CH3

•• LiLi22OO22 still observed (XRD) at cycle 5still observed (XRD) at cycle 5•• 0.75V hysteresis at cycle 1 without use of a catalyst but the c0.75V hysteresis at cycle 1 without use of a catalyst but the charge harge

profile changes while cyclingprofile changes while cycling

XR

DDimethylformamide

DE

MS

discharge 5

charge 5

charge 1

discharge 1

e-/O2

1.97 1.96

Amides as electrolyte: cycling in DMF (1)Amides as electrolyte: cycling in DMF (1) 1919


•• Still ~30% LiStill ~30% Li22OO22 after 30 discharges after 30 discharges •• Accumulation of LiAccumulation of Li22COCO33 while cyclingwhile cycling

FTIR

NM

R

Amides as electrolyte: cycling in DMF (2) Amides as electrolyte: cycling in DMF (2) 2020


[4] Y. Chen et al., J. Am. Chem. Soc., 134, 18,7952-7957 (2012)

Reaction mechanism in DMFReaction mechanism in DMF 2121


DMA (Dimethylacetamide)

NMP (N-methyl-2-pyrrolidone)

•• LiLi22OO22 obtained at cycle 1 in DMA, not in NMP.obtained at cycle 1 in DMA, not in NMP.•• Decomposition of NMP is more severe than for DMA or DMFDecomposition of NMP is more severe than for DMA or DMF

Other amides as electrolyte: DMA and NMP?Other amides as electrolyte: DMA and NMP? 2222


OutlineOutline







2323


•• Carbonates or ethers are not suitable solvents for LiCarbonates or ethers are not suitable solvents for Li--Air battery.Air battery.

•• DMF is slightly better but still does not allow a sufficient cycDMF is slightly better but still does not allow a sufficient cyclability (only lability (only ~~30 cycles).30 cycles).

•• TMS proved to be unstable after few cycles while EVS decomposes TMS proved to be unstable after few cycles while EVS decomposes from the 1st cycle. from the 1st cycle.

•• Finding a stable electrolyte Finding a stable electrolyte for real practical applicationsfor real practical applications is crucialis crucial and remains and remains a top priority. a top priority.

•• The support has an influence on the reaction mechanism. A cleverThe support has an influence on the reaction mechanism. A clever selection of selection of electrode material would also be mandatory in the future.electrode material would also be mandatory in the future.

12 6

1020

30

PC

TetraglymeDMF

0102030405060708090

100

Cycle Number

% Li2O2 ideal reaction

Estimation of Li2O2 amount versus cycle number

First cycle profile of Li-O2 battery in various electrolytes

ConclusionsConclusions 2727


-1.5

-1.0

-0.5

0.0

0.5

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

Potential [V vs. Ag/Ag+]

Cur

rent

den

sity

[mA

/cm

2 ]

100mV/sec

Propylene Carbonate

Ionic Liquid PP13TFSA

(-) (+)

Electronic distribution

Ni / PP13TFSA or PC-TEATFSA (0.1M) / Glassy Carbon / O2

Ionic liquid is highly stable against OIonic liquid is highly stable against O22 radical and Li metal. radical and Li metal. It is a promising electrolyte solvent for LiIt is a promising electrolyte solvent for Li--air batteries.air batteries.

[6] H. Nishikoori, EV TEC11, Yokohama, (2011)

Perspective: Ionic Liquids (1)Perspective: Ionic Liquids (1) 2828

TOYOTA MOTOR EUROPE – AT1 divisionDEMEDEME--TFSA enhances the capacity of LiTFSA enhances the capacity of Li--OO22 battery.battery.

Perspective: Ionic Liquids (2)Perspective: Ionic Liquids (2)

2.0

2.5

3.0

3.5

4.0

0 1000 2000 3000 4000 5000C apacity, mAh/g（electrode）

Vol

tage

, V

PP13-TFSA DEME-TFSA

Discharge

Charge

2.0

2.5

3.0

3.5

4.0

0 1000 2000 3000 4000 5000C apacity, mAh/g（electrode）

Vol

tage

, V

PP13-TFSA DEME-TFSA

Discharge

Charge

Li / LiTFSA-based electrolytes / Ketjen black cathode / O2

1st cycle0.02mA/cm2

60℃

[7] H. Nishikoori, ILABS, Korea, (2012)

Ionic Liquid DEME-TFSA

2929


University of St Andrews (UK)University of St Andrews (UK)

P.G. BruceP.G. Bruce

Y. Chen Y. Chen

S. Freunberger S. Freunberger

L.J. HardwickL.J. Hardwick

University of Leuven (BE)University of Leuven (BE)

J. FransaerJ. Fransaer

S. SchaltinS. Schaltin

Toyota Motor Corporation (JP)Toyota Motor Corporation (JP)

H. NishikooriH. Nishikoori

H. IbaH. Iba

AcknowledgementsAcknowledgements 3030


Thank you for your attention !

TODAY for TOMORROWTOYOTATODAY for TOMORROWTOYOTA

Thanks for your attentionThanks for your attention


Bibliography Bibliography ‐‐ ReferencesReferences 3232

search for stable electrolytes for lithium-oxygen batteries · 2013-03-19 · search for stable...

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