Low Cost SiOx-Graphite and Olivine Materials

K. Zaghib

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

DOE-BATT Review MeetingJune 7 – 11, 2010

This presentation does not contain any proprietary or confidential information

Project ID: ES048

OverviewTimeline

• Start date: March 2009• End date: December 2012• 40% completed

Budget• Total Project Funding: $730K• FY10 funding $365K • FY09 funding $365K

Barriers• Low energy • Poor cycle/calendar life

Partners• V. Battaglia, V. Srinivasan

(LBNL)• J. Goodenough (U. Texas)• P. Roth (SNL)• C. Julien-A. Mauger (U. Paris 6)• D. Wu (Phet)• C. Sotowa (Showa-Denko)

Objective

Synthesize and evaluate doped manganese phosphate as low cost 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.

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 alternative high-capacity anode and Mn-based olivine materials in laboratory cellso prepare laminate cathode films and powders and supply

them to BATT investigators for evaluation.

Utilize in-situ, ex-situ SEM and TEM to investigate the SEI layer on the anode and phase transformation in LiFePO4.

Technical Accomplishments

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

Developed process to improve the performance of Mn-based olivine materials.

Developed in-situ and ex –situ SEM and TEM techniques to investigate the SEI layer on the anode and phase transformation in olivines and oxides.

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

The highest reversible capacity of the (SiOx +Gr) was observed with the polyimide:Capacity: Polyimide > SBR > PVDF

The cell with SBR had the highest 1st cycle coulombic efficiency (CE):1st CE: SBR > Polyimide > PVDF

Discharge/Charge: C/24T=25°C

Technical Accomplishments

PVDF SBR PolyimideCapacity (mAh/g) Capacity (mAh/g) Capacity (mAh/g)

Discharge Charge Eff. (%) Discharge Charge Eff. (%) Discharge Charge Eff. (%)

Cycle 1 642 472 73,5 995 843 85 1332 1067 80,1Cycle 2 541 394 72,8 904 861 95 1085 1058 97,5

-0.5

0

0.5

1

1.5

2

2.5

3

0 20 40 60 80 100 120

8267B (PVDF) 9119J (POLYIMIDE)9132A (WSB)

Volta

ge V

t/h

(SiOx+ Graphite (1:1)) Anode: Cut-off Voltage

V cut off 1st Ah. Eff. 2ed Ah. Eff. Rev.Cap.(mV) (%) (%) (mAh/g)

0057A 0.0 79.1 97.3 10980057B 5.0 80.1 98.4 11280055B -5.0 79.3 96.9 1111

Binder: PolyimideDischarge/Charge: C/241M LiPF6-EC-DEC+2%VC

Reversible capacity and coulombic efficiency of (SiOx + graphite) anode were affected by thedischarge cut-off voltage.

0

0.5

1

1.5

2

2.5

3

0 20 40 60 80 100 120

0055B -0.005V A 2.5V0057A 0.005V A 2.5V0057B 0.005V A 2.5V

Volta

getime / h

Technical Accomplishments

(SiOx+ Graphite (1:1)) AnodeBinder: PolyimideDischarge/Charge: C/121M LiPF6-EC-DEC+ 2%VC

The cut-off voltage had a small effect on the capacity fade with cycling at C/12A stable capacity (600mAh/g) was observed from C/4 to 2C, and still the cell delivered > 800 mAh/g in the following cycle at C/12 rate.

0

200

400

600

800

1000

0 5 10 15 20 25 30 35

SiOx-Gr (M247) d=1.181M LiPF6 EC-DEC + 2%VC

0055B (5.0mV) 0057A (0.0mV)0057B (5.0mV)

Cap

acity

(mA

h/g)

Cycles

Technical Accomplishments

0,0

0,5

1,0

1,5

2,0

2,5

3,0

0 150 300 450 600 750 900Capacity (mAh/g)

Pote

ntia

l (V)

Cycle #1 at C/12Cycle #2 at C/8Cycle #3 at C/4Cycle #4 at C/2Cycle #5 at 1CCycle #6 at 2CCycle #7 at C/12

LiMn(1-x)MxPO4 Cathode Material Scale-Up LiMn(1-x)MxPO4 material synthesis techniques:

Hydrothermal processWet milling carbon coating ∼ 2%

Electrode:

LiMn(1-x)MxPO4 (from hydrothermal synthesis) Composition:

5% VGCF, 10% carbon black, 10% PVDF

1.5L

5L10L

XRD of LiMnPO4 : wet milled and C-coated

0

50

100

150

200

250

10 20 30 40 50 60 70 80 90

LiMnPO4_0h-WetMillHTLMPWM1-CLiMnPO4_WetMill-3h-carbonLiMnPO4_01-072-7844Ortho-ZrO2_01-079-1796

Two Theta

0h

1h

3h

-The crystallinity of the olivine structure was reduced by wet milling.

XRD of LiMnPO4 : wet milled and C-coated

0

100

200

300

400

500

10 20 30 40 50 60 70 80 90

LiMnPO4_0h-WetMillHTLMPWM1-RHTLMPWM3-RLiMnPO4_01-072-7844Ortho-ZrO2_01-079-1796

Two Theta

0h

1h

3h

- The crystallinity of the carbon-coated samples increased after re-heating at 700°C.

Nano-LiMnPO4 Cathode Material

- The 1st cycle capacity of C-LiMnPO4 increased from 23 mAh/g to 70mAh/g after nano wet-mill.

2,0

2,5

3,0

3,5

4,0

4,5

5,0

0 20 40 60 80 100 120mAh/g

Pote

ntia

l (V)

Nano, Wet-mill Before Wet mill

Qrev= 70mAh/g

10h flt10h flt

25°C

Qrev= 23mAh/g

T= 25°C1M LiPF6-EC-DEC

Technical Accomplishments

LiMn(1-x)FexPO4 Cathode Material

-The reversible capacity of Fe-doped LiMnPO4 at RT increased.-A stable 4V plateau was observed even with 80% Mn.

Technical Accomplishments

2

2,5

3

3,5

4

4,5

5

0 10 20 30 40 50 60 70 80

Time /h

Volta

ge /

V

Mn:10%Mn:30%Mn:40%Mn:50%Mn:60%Mn:70%Mn:80%

Rate: C/24, T= 25°C1M LiPF6-EC-DEC

0

20

40

60

80

100

120

140

0 0,2 0,4 0,6 0,8 1x in LiMn(1-x)FexPO4

Rev

. Cap

. (m

Ah/

g)

96

98

100

102

104

EC2(

%)

Rev Cap (mAh/g)EC2 (%)

LiMn(1-x)FexPO4 Cathode Material

- The pH of the C-coated material decreased when Mn is > 0.5.

Technical Accomplishments

6

8

10

12

0 0,2 0,4 0,6 0,8 1x in LiMn(1-x)FexPO4

pH

pH (LiMnFePO4)pH (C-LiMnFePO4)

In situ SEM studies of Li(Fe,Mn)PO4 melts (low cost)

graphite crucible

furnaceinsulating ceramics

material

In-Situ Studies by TEM

I) Starting material : Fe, Li-precursor, Phosphor-precursor + polymer

heat at 700 °C in N2 gas

II) C- LiFePO4 : heat 300- 900 °C

III) Doping effect ? : Mg, V, Mn, Nb, Zr etc…

200℃ 100 nm 300℃ 400℃ 500℃

600℃ 700℃ 700℃-90min 700℃-120min

700℃-180min

N2 pressure（Pa）：1.2×10-2

Video image of surface layer changing by heating at 700℃N2 pressure：1.17×10-2Pa

5nm

TEM image (R.T., N2 pressure：1.17×10-2Pa)

In situ HRTEM of Nanostructured C-LiFePO4 During Heat Treatment

BF-TEM image and (b) HRTEM imageof the carbon-coated LiFePO4 particles at room temperature.

BF-TEM image and HRTEM image of the carbon-coated LiFePO4particles heated at 450 C.

BF-TEM image and HRTEM of the image carbon-coated LiFePO4particles heated at 900 C.

2LiFePO4 + 9/2C => 1/2Li4P2O7 + Fe2P + 9/2CO

Electrode engineering

OxideMicron

Olivinenano

VGCFD: nanoL : microm

Bindernano

Carbon

Co-grindingMixture

CoatingHead, speed, temperature, flexibility

SlurryPVDF-NMP; WSB-H20

AC : Nano

Multilayer : Oxide-Olivine, Overcharge

Oxide 14 VOxide

pH acidAl CC

Oxide 14 VOxide

pH basic

Olivine silicate

Delithiated olivine or silicate will increase the ohmic resistance between the oxide and the aluminum CC

Ohmic Barrier

T (°C)

T (°C)

Olivine has a basic pH

Combination I:1- Current collectorA- Layer with WSB ( H2O)B- Layer with PVDF ( solvent)

Combination II:A`- Layer with PVDF ( solvent)B`- Layer with WSB ( H2O)

HQ Multilayers technologies

Multilayer CATHODE:A: LiFePO4, LiMnPO4, LiFeSiO4B: LiCoO2, LiMn2O4, LiNiO2,

LiNi1/3Co1/3Mn1/3O2

Multi layer ANODE:A: Graphite , carbonB: Li4Ti5O12, Sn, Al, Ag, , SiO, Si

B or B`

A or A`

1

LiMPO4

LiMn2O4or LiNi1/3Mn1/3Co1/3O2

Current Collector

Dual Materials and Multilayer Electrodes Low-cost mixed powders:

LiMnPO4-LiMn2O4 (20%/80%)Multilayer electrodes:

LiMnPO4 –LiCo1/3Mn1/3Ni1/3O2• Overcharge protection• Improved stability from decreased oxygen generation

Current Collector

LiMn2O4or LiNi1/3Mn1/3Co1/3O2

LiMPO4

VGCF

Dispersion Quality : Retro-diffusion ModeM261

M262

M263

M264

Bad adhesion with the collector

M264

Bad mixture with VGCF

Particle conductive material

VGCF

No Contact resistance

20% LiFePO4 + 80% Li(MnNiCo)1/3 O2

1

1,5

2

2,5

3

3,5

4

4,5

5

0 20 40 60 80

9320E9320F

Volta

ge V

vs

Li- /L

i

Time (hour)

Capacity=186.3 mAh/gCE1=92.0% CE2=96.9%

1

1,5

2

2,5

3

3,5

4

4,5

5

0 0,2 0,4 0,6 0,8 1 1,2

9320E9320F

Volta

ge V

vs

Li- /L

i

X in Li 1-x

FePO4

-No problem for the cut off voltage at 2 V.-The 1st cycle CE = 93 % with 2 V cut-off voltage.

20% LiFePO4 + 80% LiMn2O4

1,5

2

2,5

3

3,5

4

4,5

5

5,5

0 20 40 60 80

9320A 2@4.5 Volt9324E 3@4.5 Volt

Volta

ge V

vs

Li- /L

i

Time (hour)1,5

2

2,5

3

3,5

4

4,5

5

5,5

0 0,2 0,4 0,6 0,8 1 1,2 1,4

9320A9324E

- For High rate , for LiFePO4, the cut off voltage is 2 V.- Capacity and cycle life is higher with 2 V cut-off voltage.- The 1st cycle CE = 85 % with 3 V cut-off voltage.

Training on 18650 cell assembly at IREQ

29

Anode and cathode consists of nano-size particles The absence of passivation films gives rise to low internal resistance and

consequently high power and long cycle life in batteries Flexibility in the choice of electrolyte No cell formation required

Nano C-LTO/Nano C-LFP

Summary With the Polyimide binder (SiOx: Gr (1:1)) anode shows a reversible capacity of

1026mAh/g and 1st CE of 80%, and stable cycling capacity of at C/12.

(SiOx: Gr(1:1)) anode shows a reversible capacity of 1026 mAh/g, 1st cycle CE of 80%, and stable cycling capacity of 990mAh/g at C/12 rate with polyimide binder.

The effect of the binder on the (SiOx: Gr (1:1)) anode performance is the following: Reversible Capacity: Polyimide > SBR > PVDF

1st CE: SBR > Polyimide > PVDF LiMnPO4 was synthesized by hydrothermal method followed by wet-milling

process: o The particle size was reduce from 0.25µm to less than 50nmo 104 mAh/g at 25°C for the 1st charge, and 70mAh/g reversible capacity.

Doped LiMnFePO4 showed a remarkable improvement of 4V plateau even with 80% Mn.

In-situ studies explored the phase transformation of olivines. Training to fabricate 18650 cells started.

Future Activities Rest of this year Continue evaluation of mixed graphite-SiOx as an alternative anode.

Continue improving the performance doped LiMnMPO4 as low cost cathode for Li-Ion cells.

Conduct in-situ SEM and TEM studies of olivines and oxide-olivines.

Investigate dual oxide-olivine by coating the oxide (1/3 and LiMnAlO2) with olivine (improve performance at different SOC and energy-power, safety performance).

Evaluate dual oxide-olivine as mixed powders or multilayer structures in cathodes

Continue supplying laminated electrode, powders and 18650 cells to investigators in the BATT program.

Fabricate and test 18650 cells with oxide-LiM1M2PO4 cathodes and SiO/graphite anodes, and provide cells to investigators in the BATT program for evaluation.

All milestones completed