Low Cost SiOx-Graphite and High Voltage Spinel Cathode

K. Zaghib

Hydro-Québec (IREQ), 1800 Lionel-BouletVarennes, QC, Canada, J3X 1S1

DOE-BATT Review Meeting

May 9-13, 2011This presentation does not contain any proprietary or confidential information

ID # ES048

Overview

Timeline• Start date: March 2009• End date: December 2012• 60% completed

Budget• Total Project Funding: $1095K• FY11 funding $365K• FY10 funding $365K • FY09 funding $365K

Barriers• Low energy • Poor cycle/calendar life

Partners• V. Battaglia, V. Srinivasan and R.

Kostecki (LBNL)• J. Goodenough (U. Texas)• M. Thackeray (ANL)• C. Julien, A. Mauger (U. Paris 6)• X.Q. Yang (BNL)

Objectives

Synthesize and evaluate LiMn3/2Ni1/2O4 as high voltage cathode material.

Replace graphite anode with an alternative material that meets the requirement for low cost and high energy.

Develop in-situ and ex-situ SEM and TEM techniques to analyze the SEI layer properties.

Cell assembly of 18560 with the BATT chemistry.

Approach HQ efforts in the BATT program to investigate and improve SEI

layers on alternative anodes include several tasks:o Prepare laminate anode films and powders, and supply them to

investigators in Topic 3a involved with SEI analysis using different techniques (in-situ, ex-situ).

o Identify benefits of binder (SBR, Polyimide, EPDM) compared to PVDF in new anode and cathode materials.

Investigate performance of high-voltage spinel cathode in laboratory cells.o Stabilize the LiMn3/2Ni1/2O4 cathode by protecting its surface with

more stable material to suppress the secondary reaction with the electrolyte.

o Synthesize LiMn3/2Ni1/2O4 at HQ and supply the optimized material to BATT investigators for evaluation.

Utilize in-situ and ex-situ SEM and TEM to investigate the SEI layer on the anode and cathode.

MILESTONES

Completed evaluation of the effect of the binder on the SiOx anode performance.

On going

Developed process to stabilize the surface of theLiMn3/2Ni1/2O4 cathode.

Synthesized LiMn3/2Ni1/2O4 cathode material and supply BATT investigators.

Developed in-situ and ex –situ SEM and TEM techniques to investigate the SEI layer on the anode and the interface on the LiMn3/2Ni1/2O4 oxide spinel.

Evaluation of 18650 cells assembled at HQ

(C-SiOx+ Graphite (1:1)) AnodeBinder: polyacrylonitrile butadiene1M LiPF6-EC-DEC+ 2%VC

- By using polyacrylonitrile butadiene as binder, the 1CE was 80% and the reversible capacity was 972mAh/g.- The constant voltage step at discharged state (50mV) improves the cycling performance.

Technical Accomplishments

0

0,5

1

1,5

2

2,5

3

0 20 40 60 80 100 120

0312C

Volta

ge

time (h)

CE1:80% CE2:99% Rev. Cap.: 972 mAh/g

0

200

400

600

800

1000

0 10 20 30 40 50

0312A

Capa

city

mAh

/g

# cycle

1h Constant Voltage at 50mV

Constant current at C/6

C/24

(C-SiOx+ Graphite (1:1)) Anode: In-SituBinder: PolyimideDischarge/Charge: C/241M LiPF6-EC-DEC+2%VC

Discharge

Discharge

Discharge

Discharge

Charge

Charge

SiGr

Technical Accomplishments

- The in-situ studies revealed that larger particles (∼13µm) start to develop cracks at around 0.1V and the smaller particles (< 2μm) are more stable.-Some fissures were observed and the particles are delaminated .

Movie

(C-SiOx+ Graphite (1:1)) Anode: In-Situ

Si-Based Anode

C-SiOx-graphite D50 ∼ 8µm Bigger particle (∼13µm)

cracks during the first discharge

In-situ SEM

Si nano

Smaller particle is needed

EC1: 80%1058 mAh/g

Si-Nano Material for AnodeLi coin type cellBinder: Polyimide1M LiPF6-EC-DEC+2%VC

The reversible capacity was only 1220mAh/g for the Si-nano material at low rate: Carbon coating is needed In situ SEM studies needed to analyze low-capacity behavior.

Discharge/Charge: C/48T=25°C

Technical Accomplishments

Cell: 0300A 0300BEC1 (%): 50 49 EC3 (%): 96 96Qrev (mAh/g): 1224 1153

0

0,5

1

1,5

2

2,5

3

-20 0 20 40 60 80 100 120 140

0301A 0301B

Volta

ge

t/h

C/48

Cathode Material Plan

HQ Synthesis LiMn3/2Ni1/2O4

Optimized material be will sent to the

BATT PIs

LFP coated LMN(dry process)

Surface protection of LMN cathode

High Voltage CathodeLiMn3/2Ni1/2O4

Oxide and ceramic LMN surface treatment

(wet process)

- Ni-O- Mn-O- LiCoPO4- AlPO4

Charging LiMn3/2Ni1/2O4 requires high voltage (4.9V), which could induce it’s degradation in performance. Protecting the LiMn3/2Ni1/2O4 surface can minimize this side reaction.

-The LiMn3/2Ni1/2O4 was successfully coated with LiFePO4 using dry process.

LiFePO4 Coated LiMn3/2Ni1/2O4: SEM

LiMn3/2Ni1/2O4 Dry process LFP(LiMn3/2Ni1/2O4

-The LiMn3/2Ni1/2O4 was successfully coated with LiFePO4 using dry process.

EC1(%)

EC2(%)

Cap(mAh/g)

LFP coated (LiMn1.5Ni0.5O4)

76 88 123

LiMn1.5Ni0.5O4 67 86 104

LiFP(LiMn1.5Ni0.5O4):20(80) Wt%Discharge/Charge: C/241M LiPF6-EC-DEC+ 2%VC

Technical Accomplishments

LiFePO4 Coated LiMn3/2Ni1/2O4: Formation

2,5

3

3,5

4

4,5

5

5,5

0 20 40 60 80 100

1060M LMN0323A LFP coated LMN

Volta

ge V

sv

Li- /L

i

t/h

LFP

-The high power performance was improved With LFP-coated LiMn3/2Ni1/2O4.

LiFePO4 Coated LiMn3/2Ni1/2O4: Ragone Test

0

20

40

60

80

100

120

140

0,0 0,1 1,0 10,0 100,0

Rate (C)

Cap

acity

(mA

h/g)

0323A 80% LiMn1.5Ni0.5O4 20% LiFePO4 1060K LiMn1.5Ni0.5O4

3 @ 4.9Volt

0323A LFP coated Li1Mn1,5Ni0,5O4

LFP effect

2,5

3,0

3,5

4,0

4,5

5,0

5,5

0 30 60 90 120 150Capacity (mAh/g)

Pote

ntia

l (V)

C/12 C/8 C/4C/2 1C 2C4C 8C 10C15C 20C

2,5

3,0

3,5

4,0

4,5

5,0

5,5

0 30 60 90 120 150Capacity (mAh/g)

Pote

ntia

l (V)

C/12 C/8 C/4C/2 1C 2C4C 8C 10C15C 20C

Technical Accomplishments

LFP

LMN without coating

LMN with LFP coating

Technical Accomplishments

0

200

400

600

800

1000

0 200 400 600 800 1000

9279A: (LiMn1.5

Ni0.5

O4)

0323A: LFP(LiMn1.5

Ni0.5

O4)

-Im (Z

') / O

hm

Re (Z) / Ohm

0

20

40

60

80

100

0 20 40 60 80 100

9279A: LiMn1.5

Ni0.5

O4

0323A: LFP(LiMn1.5

Ni0.5

O4)

-Im (Z

') / O

hm

Re (Z) / Ohm

-A comparable interface was obtained after the formation cycles.-The interface changed after high rate test to the LFP-coatedLiMn3/2Ni1/2O4.

LiNi0.5Mn1.5O4 before and after LFP coating

0 50 100 150

-150

-100

-50

0

Z'

Z''

0323A After LFP coating.z9279A Before LFP coating.z

9279:LiMn1.5Ni0.5O4

0323: LFP(LiMn1.5Ni0.5O4)

Cells before formation

Cells after formation

Cells after high rate test

LiFePO4 Coated LiMn3/2Ni1/2O4: Interfaces

-The LFP-coated LiMn3/2Ni1/2O4 cathode showed less capacity fade (3-4.9V) cycled at 1C compared to uncoated one.

Technical Accomplishments

LiFePO4 Coated LiMn3/2Ni1/2O4: Cycling

1C

0

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0 20 40 60Cycle Number

Cap

acity

(mA

h/g)

0323A 80% LiMn1.5Ni0.5O4 20% LiFePO41061D LiMn1.5Ni0.5O4

C:C/4, D: 1C3 @ 4.9 volt

0323A LFP coated LiMn1.5Ni0.5O4

Solid-State process (SS sample)

nickel acetatesolution

mixed with Li2CO3and MnCO3

stir and dryat 90°Cground

final heating at 800 - 900 °C for 24h

Co-Precipitation method (CP sample)

Li, Mn, Niacetates solution

dropped into oxalic acid solution

stir and dry at 90°Cground

groundpreheated at 400°C 6h in air

final annealing at 800-900 °C for 24h

preheated at 700°C ground

LiMn3/2Ni1/2O4: HQ-Synthesis

3 samples of LiMn1.5Ni0.5O4 were sent to Vince Battaglia (LBNL) for evaluation.

-Trace impurities (2θ = 38° and 45°) were found in HQ samples, probably due to loss of oxygen and/or lithium at high temperature. - Samples crystallize better with disordered structure at higher temperatures.

HQ Synthesis of LiMn3/2Ni1/2O4: XRD

(a) Company sample (b) Co-Precipitation (CP) sample

(c) Solid State (SS) sample

Particle size: SS > CP > company sample

HQ Synthesis of LiMn3/2Ni1/2O4: SEM

HQ Synthesis of LiMn3/2Ni1/2O4: Formation

Mn4+ / Mn3+ redox couple

Company A, C/12

The oxygen deficiency under high annealing temperature resulted in the Li1-x-Nix-O impurities (2θ = 38° and 45° in XRD) as well as small amount of reduced Mn3+ (Mn4+/Mn3+) redox couple shows voltage plateau at 4.1 V).

Materials synthesized at higher temperature show improved results

HQ Synthesis of LiMn3/2Ni1/2O4: Cycling

020406080

100120

0 5 10 15 20 25 30Cycle Number

Cap

acity

(mA

h/g

)

0362A 800 °C 0362B 800 °C 0362C 900 °C 0362D 900 °C

C/12 3 @ 4.9 Volt

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140

0 20 40 60 80 100 120

Company A0348H S.S 900C0348F S.S 800C

Cap

acity

mA

h/g

Cycle #

LiCoPO4 -Coated LiMn3/2Ni1/2O4

With traditional sol-gel method, no obvious impurities were detected in LiCoPO4 -coated LNM, but the diffraction peaks shift to lower angles, indicating the lattice parameters change after coating, probably some of the Mn4+ were reduced to Mn3+ in Ar.

LiCoPO4 coated LNM in Ar1 wt.% LiCoPO4 coated-LNM

5 wt.% LiCoPO4 coated-LNM

Summary Si Based Anode

The C-SiOx-graphite based anode with the polyacrylonitrile butadiene binder showed a reversible capacity of 972mAh/g and 1st coulombic efficiency of 80%, and quite stable cycling capacity at C/6.

The effect of the binder on the (SiOx: Gr (1:1)) anode performance is the following: Reversible Capacity: Polyimide > polyacrylonitrile butadiene > SBR > PVDF1st coulombic efficiency: SBR > polyimide = polyacrylonitrile butadiene > PVDF

In-situ studies of the SiOx anode showed evidence that the larger particles (~ 13μm) start to crack at about 0.1V, but the smaller particles (< 2μm) are stable. Also some fissures were observed and the particles delaminate.

Si-nano material based anode with the polyimide binder showed a reversible capacity of 1150mAh/g and 1st coulombic efficiency of 50%.

Spinel LiMn3/2Ni1/2O4 Cathode Material

Trace impurities observed in HQ-synthesized LMN samples; higher temperature leads to better crystallization with disordered structure. The highest reversible capacity obtained was 140mAh/g.

C-LiFePO4 nano-particles were coated on the LMN surface using a dry process, and promising results were obtained at 1C rate.

LiCoPO4 coating in argon does not change the bulk structure of LMN, but some Mn4+ may be reduced to Mn3+.

Developing in-situ SEM and TEM tools for the anode and cathode materials.

Evaluation of 18650 cells fabricated at HQ was started.

Future Activities Remainder of this year

Continue evaluation of mixed graphite-SiOx and nano-Si as an alternative anode.

Continue improving the performance of the HQ-synthesized LiMn3/2Ni1/2O4 cathode for high energy, and send the optimized samples to PIs in the BATT Program for evaluation.

Continue exploring surface stabilization of the high-voltage LiMn3/2Ni1/2O4 cathode.

The successful in-situ SEM studies on the anode has encouraged us to continue studies on the Si and SiOx with different binders, and to investigate the surface of LiMn3/2Ni1/2O4 cathodes.

Evaluate high-voltage stable electrolytes with LiMn3/2Ni1/2O4 cathode.

The 18650 cells fabricated at HQ show promising results that will be helpful to other BATT investigators who want to take advantage of the HQ coating, calendering equipment and cell assembly facilities.

Fabricate and test 18650 cells with oxide-LiMn3/2Ni1/2O4 cathodes and SiOx/graphite anodes, and provide cells to investigators in the BATT program for evaluation.

All milestones completed

Technical Back-up Slides

r-\ Hydro ~ Quebec

Installation for fabrication of 18650 cylindrical cells

18650 Cells LTO/LFP

200

400

600

800

1000

5000 10000 15000 20000 25000 30000

Cell: charge 15C // discharge 5CCell: charge 10C // discharge 5C

Dis

char

ge C

apac

ity (m

Ah)

Cycle Number

18650: LTO//LFP

Electrolytes Stable at High voltageElectrolyte Configuration

1st EC (%)

Rev. Cap.

(mAh/g)

1M LiPF6 in 25:25:50 v/v/v EC: DMC : Sebaconitrile 70 111

1M LiPF6 in 25:25:50 v/v/v EC: DMC : Methoxypropionitrile 24 73

1M LiPF6 in 39:39:22 v/v/v EC: DMC : Adiponitrile 59 116

1M LiPF6 3:7 v/v EC : DEC 67 104

2,5

3

3,5

4

4,5

5

0 20 40 60 80 100

C/24 , 3 @ 4.9 Volt

1060O 1M LiPF6 in 25:25:50 v/v/v EC: DMC : Sebaconitrile1060P 1M LiPF6 in 25:25:50 v/v/v EC: DMC : Methoxypropionitrile1060T 1M LiPF6 in 39:39:22 v/v/v EC: DMC : Adiponitrile1060M 1M LiPF6 3:7 v/v EC : DEC

Volta

ge V

sv

Li- /L

i

time (h)

-The best charge-discharge performance was obtained during the formation cycles with an electrolyte containing Sebaconitrile as additive.

0

20

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0 20 40 60 80 100 120

Comapany A 0348B 1% Mn-O(LiMn1.5Ni0.5O4)0348C 1%Ni-O(LiMn1.5Ni0.5)

Cap

acity

mA

h/g

Cycle #

Oxide-coated LiMn3/2Ni1/2O4:

LiMn(1-x)FexPO4 Cathode Material

-The substituted LiMn1-xFexPO4 suffers at high rates, and the composition limit for power application should not exceed Mn content of 0.5.

(SiOx+ Graphite (1:1)) Anode: Binder EffectLi coin type cell1M LiPF6-EC-DEC+2%VC

Discharge/Charge: C/24T=25°C

0

0,5

1

1,5

2

2,5

3

3,5

0 20 40 60 80 100 120

8267B (PVDF)9119J (Polyimide)9132A (WSB)0312C (Polyacrylonitrile butadiene)

Volta

ge V

vs

Li

time (h)

C24

PVDF WSB Polyimide polyacrylonitrile butadiene

Capacity (mAh/g) Capacity (mAh/g) Capacity (mAh/g) Capacity (mAh/g)Discharge Charge Eff. (%) Discharge Charge Eff. (%) Discharge Charge Eff. (%) Discharge Charge Eff. (%)

Cycle 1 642 472 74 995 843 85 1332 1067 80 1177 941 80Cycle 2 541 394 73 904 861 95 1085 1058 98 984 972 99