Progress in rechargeable Li ion batteries.

At Bar Ilan University:Elena MarkevichGregory SalitraElla ZinigradBoris Markovsky

Mikhail LeviAt Merck KGaA:Guenter SemrauMichael SchmidtAt HPLIvan ExnarAt GMIon Halalay At Sion PowerCharlie s. Kelley At TadiranHerzel YaminAt ETVArie Neitav & Shalom Luski

Doron Aurbach

Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel

Support: ISF , Israel Science Foundation.Chief Scientist (MAGNETON programs).ETV,TAMI (Israel)Merck KGaA (Germany), LG Korea).GM, Sion Power (USA).In collaboration with UBE Industries, Japan.

Introductory remarks.On polar aprotic solutions for Li ion batteries.On the use of ionic liquids for rechargeable Li electrodes: 5 V cathodes, Li-Graphite, Li-Si.Comparative study of cathode materials:

LiMn1.5Ni0.5O4 spinelLiNi0.5Mn0.5O2LiNi0.33Mn0.33Co0.33O2LiNi0.4Mn0.4Co0.2O2LiNi0.8Co0.15Al0.05O2LiMnPO4 two generations.

Aging, stability, rate capability, cycle life and surface chemistry.Conclusion.

Outline

Solvents for Li batteries

SolutionMw [g/mol]m.p. C°

b.p C°.

Dielectric

ε

viscosity Cp

(γ)density

gr/ccDonor #

EC88.0636.424389.6 ) c°40 (1.861.321816.4

PC49-24164.42.531.1915.1

DMC90.08390.53.120.57-0.581.0636-

DEC118.1343-1262.820.969215.1

THF108.5-657.390.460.88

EMC104.1114-107.52.961.012-

Interesting additives (UBE Industries)Surface reactive compounds that polymerize on both anodes and cathodes VC PMS

LiAsF6 toxicLiClO4

explosiveLiBF4

poor passivationLiBOB limited anodic stability Li(NSO2

CF3

)2 poor passivation LiPF6

Choiceof salts

LiPF6

↔

LiF + PF5PF5

+ H2

O →

2HF + PF3

O

The best compromise

Side products: LiF, PF5

,HF, POF3

0

5

10

15

20

25

30

35

40

130 150 170 190 210 230 250 270 290 310 330

'Z/ohm cm2

-"Z/

ohm

cm

2

DOL+LiTFSI+LiNO3

DOL+LiTFSI

DOL+LiTFSI+PS+LiNO3 DOL+LiTFSI

+PS

1.5

1.6

1.7

1.8

1.9

2

2.1

2.2

2.3

2.4

2.5

0 200 400 600 800 1000 1200

Capacity [mAh/g]

V vs

. Li

a b

Sulfur XPS spectra of Li electrodes prepared and stored in 1,3-dioxolane solutions

Solution containing only Li2

S6 Solution containing both Li2

S6

and LiNO3 Note the highoxidation stateof Li surface sulfur due to the presence of LiNO3The passivationof Li is due to the formation ofvarious Li-S-Ocompounds

Voltage profiles of Li-S cells based on dioxolane & LiN(SO2

CF3

)2 solutions

Shuttle mechanism,Low capacityDue to poly-sulfidereduction on the Li anode and their repeated oxidation on the cathode

Solution containing LiNO3

Impedance spectra of Li electrodes prepared fresh in dioxolane LiTFSI solutions : with no additives ; with LiNO3

; with Li2

S6and with LiNO3

+ Li2

S6

Rechargeable Li sulfur cells: The highest energy density due to

the high electrodes capacityEthereal solvents such as 1-3 Dioxolane + an electrolyte such as LiN(SO2

CF3

)2A major problem: limited capacity of the sulfur cathode due to shuttle mechanism.

-40 -20 0 20 40 60 8

0

5

10

15

20

EC:DMC(1:2)1.5m LiPF6 Standard

EC:EMC (3:7)1m LiBF4

PC:EC:EMC (1:1:3)1m LiBF4

EC:DEC:DMC:EMC(3:5:4:1)1m LiPF6

EC:DMC:EMC (15:37:48)1m LiTFSI

EC:DEC:DMC:EMC(1:1:1:2)1m LiPF6

EC:DMC:EMC (15:37:48)1m LiPF6

EC:DEC:DMC:EB(1:1:1:1)1m LiPF6

EC:DEC:DMC:BL(1:1:1:1)1m LiPF6

mS

Temperature (oC)

Conductivity results obtained for different electrolytes at various temperatures.

-50 -40 -30 -20 -10 0 10 20 30 40

0

100

200

300

400

Dis

char

ge C

apac

ity (m

Ah/

g)

Temperature (oC)

0 100 200 300 4000.0

0.5

1.0

1.5

30 oC 1st Cycle

Volta

ge (V

)

Discharge Capacity (mAh/g)

0 10 20 30 40 50 600.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

-30 oC 1st Cycle

Discharge Capacity (mAh/g)

Volta

ge (V

)

Kansai coke graphite NG15 in standard electrolyte EC:DMC 1.5M LiPF6

. Inset graph shows the Voltage Vs Discharge capacity at 30 and -30 oC temperature.

-40 -30 -20 -10 0 10 20 30 40

0

100

200

300

400

500

600 EC:DMC:EMC-1M LiPF6+1% VC

Kansai Coke N15 Conoco Philips G5 Timcal SLP-30

Dis

char

ge C

apac

ity (m

Ah/g

)

Temperature oC-50 -40 -30 -20 -10 0 10 20 30 40

0

100

200

300

400

500

Temperature oC

Dis

char

ge C

apac

ity (m

Ah/

g)

EC:DMC:EMC-1M LiTFSI +1% VC

Kansai Coke N15 Conoco Philips G5 Timcal SLP-30

Performance of different graphite materials in two different electrolytes at various temperatures.

Low-temperature electrolytes for Li-batteries

Low temperature performance of different cathode and anode materials in various electrolytes

-40 -30 -20 -10 0 10 20 30 40-20

0

20

40

60

80

100

120

140

160

180

200

Temperature oC

Dis

char

ge C

apac

ity (m

Ah/

g)

EC:DMC:EMC-1M LiPF6 + 1% VC EC:DMC:EMC-1M LiTFSI + 1% VC EC:DMC:EMC-0.9M LiTFSI + 0.1M LiBOB +1% VC EC:DEC:DMC:BL-1M LiPF6 +1% VC EC:DEC:DMC:EB- 1M LiPF6 +1% VC

-40 -30 -20 -10 0 10 20 30 400

20

40

60

80

100

120

140

160

180

200

220

EC:DMC:EMC-1M LiPF6 + 1% VC EC:DMC:EMC-1M LiTFSI + 1% VC EC:DMC:EMC-0.9M LiTFSI + 0.1M LiBOB +1% VC EC:DEC:DMC:BL-1M LiPF6 +1% VC EC:DEC:DMC:EB- 1M LiPF6 +1% VC

Temperature oC

Dis

char

ge C

apac

ity (m

Ah/

g)

Lithium Titanate (Li4

Ti5

O12

) NMC (LiNi1/3

Mn1/3

Co1/3

O2

)

0 20 40 60 80 100 120 140 160 1801.0

1.5

2.0

2.5

3.030 deg. -red (1)0 deg. -green (5)-10 deg. -blue (7)-20 deg. -cyan (9)-30 deg. -Magenta (11-40 deg. -Purple(13)30 deg. -wine (16)(repeat after low temperature measurement)

Volta

ge (v

)

Discharge capacity (mAh/g)0 20 40 60 80 100 120 140 160 180

2.5

3.0

3.5

4.0

4.5

30 deg. -red (1)30 deg. -green (2)0 deg. -blue (8)-10 deg. -cyan (13)-20 deg. -Magenta (21)-30 deg. -dark yellow (33)-40 deg. -wine (48) 30 deg. pink (59)(repeat after low temperature measurement)

Volta

ge (V

)

Discharge capacity (mAh/g)0 20 40 60 80 100 120 140 160 180 200

2.5

3.0

3.5

4.0

4.5

30 deg. -red (1)30 deg. -green (2)0 deg. -blue (8)-10 deg. -cyan (11)-20 deg. -Magenta (18)-30 deg. -dark yellow (28)-40 deg. -wine (40) 30 deg. (49)(repeat after low temperature measurement)

Vol

tage

(V)

Discharge capacity (mAh/g)0 20 40 60 80 100 120 140 160 180

1.0

1.5

2.0

2.5

3.030 deg. -red (1)0 deg. -green (4)-10 deg. -blue (6)-20 deg. -cyan (9)-30 deg. -Magenta (10)-40 deg. -Purple (12)30 deg. -wine (15) (repeat after low temperature measurement)

Vol

tage

(V)

Discharge Capacity (mAh/g)

Voltage Vs Discharge capacity curve of Li4

Ti5

O12

and LiNi1/3

Mn1/3

Co1/3

O2

at various temperature in different electrolytes.

Li4

Ti5

O12LiNi1/3

Mn1/3

Co1/3

O2

EC:DEC:DMC:EB-

1mLiPF6

+1%VCEC:DMC:EMC-1mLiPF6

+1%VCEC:DMC:EMC-1mLiPF6

+1%VC EC:DMC:EMC-1mLiTFSI +1%VC

-30

-20

-10

0

10

20

30

40

4.1 4.3 4.5 4.7 4.9 5.1

E, V

I, μA

2

1side

parasitic oxidation processes in standard electrolytes not in Ils

Kinetics is slower in the ionic liquid electrolyte

LiNi0.5 Mn1.5 O2 /Li “5V” cells demonstrate stable cycling with IL electrolyte

solutions : elaboration of real “5V” rechargeable Li batteries may be feasible.

LiNi0.5

Mn1.5

O2

electrodes in 1.5M LiPF6

EC/EMC 1:2 and in

IL solution 0.5M LiTFSI in MPPpTFSI

N

C3H7

N(SO2CF3)2

Why Ionic Liquids (Ils)?Wide electrochemical window

Safety

0 1 2 3 4 5 6-0.10m

-0.05m

0

0.05m

0.10m

0.15m

0.20m

E / V vs. Li/Li+

i / A

The electrochemical stability window

of LiTFSI in MPPpTFSI electrolyte

Pt and LiNi0.5

Mn1.5

O2

electrodes

0

100

200

300

400

0 20 40

Cycle number

Cap

acity

/mA

H g

-1

`

-30

-20

-10

0

10

20

30

40

4.1 4.3 4.5 4.7 4.9 5.1E/V

I/μA

Charge and discharge capacity obtained for the galvanostatic cycling of LiNi0.5

Mn1.5

O2

electrodes (C/16). Upper curves are discharge proesses and the lower curves are the charging processes. Note the much lower irreversible capacity obtained with the ILs electrolytes.

V. Burgel et Al, J. Power Sources (2008) In press

0.5M LiTFSI in BMPTFSI

1.5M LiPF6

in EC/EMC 1:2

LiNi0.5

Mn1.5

O4

electrodes in standard & IL solutions

0.5M LiTFSI in MPPpTFSI

20μV/s, 200C

A comparative study of the behavior of different kinds of graphite electrodes in solutions based on ionic liquids

Cycle 3

Cycle 2

Cycle 1

Cycle 3

Cycle 2

Cycle 1 Natural graphiteSynthetic flakes,

40 micron

-35

-25

-15

-5

5

0 0.5 1 1.5 2 2.5 3 3.5

E, V

I, μA

Graphite in pure IL (MPPpTFSI): no Li ions,no passivation, irreversible IL intercalation

IL + Li saltIL + Li salt

-6

-4

-2

0

2

4

-0.5 0 0.5 1 1.5 2 2.5 3 3.5

E, V

I, μA

Cycle 1

Cycle 3

Cycle 2

-6

-4

-2

0

2

4

-0.5 0 0.5 1 1.5 2 2.5 3 3.5

E, V

I, μA

Cycle 1

Cycle 3

Cycle 2

Natural graphite

NGSynthetic flakes

150 200 250 300 350

0.5 W/g of Li0.5

CoO2

197 ºC

Standard solution+10 % BMPFAP

667 J/g

168 ºCStandard solution+10 % BMPTFSI

286 J/g

156 ºC Standard solution EC-DMC LiPF6

1M

1860 J/g

254 ºCLi0.5

CoO2

no solution330 J/g

exo

Hea

t flo

w

Temperature, ºC

DSC response of Li0.5

CoO2

+ solutions

+N

C4H9

N(SO2CF3)2N(SO2CF3)2

+N

C4H9

PF3(C2F5)3PF3(C2F5)3

Attenuation of thermal activity by use of ILs as additives

SynthesisSingle-step sucrose-aided Self-Combustion Reactionfor production of layered compounds of nanosized lithiated oxidesLiNO3

+ 0.5 Ni(NO3

)2

.6H2

O + 0.5 Mn(NO3

)2

.4H2

O+ 0.3125 C12

H22

O11

+ 0.25 O2LiNi0.5

Mn0.5

O2

+ 3.75 CO2

+ 8.4375 H2

O + 3 N2Then, calcination provides the final structure.The temp. & time of calcination determine the particle size.

900 0C (22 hours)

Particle size, μm

OXIDIZERMetal Nitrates

REDUCER (FUEL)Sucrose(C12H22O11)

PRODUCT Nanosized + GasesMaterial (CO2, NxOy)

Solution Syrupy mass Foam Self-ignition

OXIDIZERMetal Nitrates

REDUCER (FUEL)Sucrose(C12H22O11)

PRODUCT Nanosized + GasesMaterial (CO2, NxOy)

Solution Syrupy mass Foam Self-ignition

0.01 0.21 0.41 0.61 0.81 1.01 1.21 1.41 ParticleSize(µm)

0

5

10

15

20

25

30

35

Num

ber (

%)

Num

ber (

%)

Particle size, μm

Particle size, µm

Num

ber,

%

700oC for 22h

900oC for 22h

25 nm

Nano-sized LiNi0.5

Mn1.5

04 vs. Micro-sized LiNi0.5

Mn1.5

04

0

100

200

300

2-Theta - Scale11 20 30 40 50 60 70

111

311 400

222 331 333 440531

W=0.17

W=0.32

W=0.18

W=0.46

W=0.25

W=0.48

Micro-sized particles

Nano-sized particles

Inte

nsity

/ cou

nts.

s-1

Raman shift/ cm-1100 200 300 400 500 600 700 800 900

407

500

640

Micro-sized particles

Nano-sized particles

50

50592

Inte

nsity

/ a.u

.

496

596

638

400

w=28

w=19w=13

w=75

w=31w=32

530

527

ν=300 μVs-1, T=300C

E/ V4.3 4.4 4.5 4.6 4.7 4.8 4.9

I/ A

.g-1

-2e-6

-1e-6

0

1e-6

2e-6Micro-particles Nano-particles Ni3+ Ni4+

Ni2+ Ni3+

Ni3+ Ni4+Ni2+ Ni3+

XRD

Raman

We have synthesized nano particles of the right material, it behaves indeed faster!

E / V v s . L i /L i +

4 .3 4 .4 4 . 5 4 .6 4 .7 4 .8 4 .9

I / A

.cm

-2

- 2 e - 6

- 1 e - 6

0

1 e - 6

2 e - 6P r is t in e p a r t ic le sP a r t ic le s a g e din s o lu t io n ( 7 0 0 C )

S c a n r a te 1 0 μ V / s

4 . 7 1 V

4 .7 6 V

4 .7 2 V

4 .6 9 V

Up to 140 mAh/gHundreds ofcycles

70 0C

Z' / Ohm.cm20 4 8 12 16 20

-4

-2

0

0 4 8 12 16 20

-4

-2

0

0 4 8 12 16 20

Z'' /

Ohm

.cm

2

-4

-2

0

0 4 8 12 16 20

-4

-2

0

250 Hz 1 Hz 5 mHz

250 Hz 1 Hz5 mHz

200 Hz 2.5 Hz 5 mHz

200 Hz 1.25 Hz

63 mHz

Micro-particles

Z' / Ohm.cm20 50 100 150 200 250

-100

-50

0

0 50 100 150 200 250

Z'' /

Ohm

.cm

2 -100

-50

0

0 50 100 150 200 250

-100

-50

0

200 Hz

316 mHz

2.5 Hz

25 mHz

5 Hz

20 mHz

Initial (steady-state)

30 days cycling/ageing

50 days cycling/ageing

2 weeks ageing

1 week ageing

LiNi0.5

Mn0.5

O2

Electrodes: 600C, E=3.90 V

Nano-particles

0

40

80

120

160

200

0 20 40 60 80Dis

char

ge c

apac

ity /

mA

hg-1

Total charge (cc-cv) capacity Discharge capacityC/10

C/4C/2

2C

7.5C

C/7

Cycle number100 200 300 400 500

Dis

char

ge c

apac

ity /

mAh

g-1

40

80

120

160

200

C/5

3C

8C 3C

Aging at 300C for 1 weekevery 100 cycles

Submicron-

LiNi0.33

Mn0.33

Co0.33

O2

Submicron-

LiNi0.4

Mn0.4

Co0.2

O2

Cycle number

0 5 10 15 20 250

50

100

150

200

250

Total charge (CC-CV) capacity Discharge capacity

3C

1 C

C/2

C/5

C/15

Cap

acity

/ m

Ah.g

-1

Cycle number5 10 15 20 25 30 35 40

Dis

char

ge c

apac

ity /

mA

hg-1

40

80

120

160

200

C/2.51C

2C

6C 6C

C/5

Submicron-

LiNi0.33

Mn0.33

Co0.33

O2

Very fast material

0 10 20 30 40

50

100

150

200 C/15 C/10C/10

4 C

2 C

C/2C/5

1 C

Cap

acity

/ m

Ahg

-1

Total charge (CC-CV) capacity Discharge capacity

Submicron-

LiNi0.8

Co0.15

Al0.05

O2

Cycle number

Electrochemical behavior of electrodes prepared from micro-, submicron or nano-particles in Li cells, DMC-EC/LiPF6

solutions

0 50 100 150 200 250 300

50

100

150

200

250 Total charge (CC-CV) capacity Discharge capacity

C/5

1CCap

acity

/ m

Ah.

g-1

2

Submicron-

LiNi0.5

Mn0.5

O2Very good cyclability

Cycle numberCycle number

Submicron-

LiNi0.5

Mn0.5

O2

0 25 50 75 100 125 150 175 200

2.5

3.0

3.5

4.0

4.5

NCA

4C 2C C C/2 C/5

C/10

C/15

Cel

l vol

tage

(V)

Discharge capacity (mAhg-1)

Voltage profile for LiNi0.5

Mn0.5

O2

, NCA and C-coated LiMnPO4 composite electrodes at various discharge rates at 30oC

0 25 50 75 100 125 1502.5

3.0

3.5

4.0

4.5

C-coated LiMnPO4

Discharge capacity / mAhg-1

C/10

C/25

C/5C/2C2C5C

Cel

l vol

tage

/ V

0 25 50 75 100 125 150 175 200

2.5

3.0

3.5

4.0

4.5

LiNi0.5Mn0.5O2

3C C/5C C/2 C/15

Cel

l vol

tage

(V)

Discharge capacity (mAhg-1)

Comparison of cycling behavior at various rates of discharge for

Gen 1 and Gen 2 electrodes

at 30o C

0 10 20 30 40 5040

60

80

100

120

140

160

180

30C

10C

5C

2C

1C

Dis

char

ge c

apac

ity /

mAh

g-1 C/2C/5C/10C/20

Cycle number

Gen 1 (2.7 V - 4.4 V)Gen 2 (2.7 V-4.25 V)

0 20 40 60 80 100 120 140 16050

100

150

200

250

300

350

400

4.4 V-2.7VEC-DMC/LiPF6 electrolyte

C/5

C/2

C/20

Total charge (CC-CV) capacity Discharge capacity

Cap

acity

/ m

Ahg-1

Cycle number

Cycling behavior at C/5 rate of discharge forGen 2

electrodes

at 30o C

Comparison of capacity at various discharge rates for the electrodes comprising LiNi0.5

Mn0.5

O2

, LiNi0.33

Mn0.33

Co0.33

O2

, LiNi0.8

Co0.15 Al0.05

O2

, (NCA), LiNi0.4

Mn0.4

Co0.2

O2 , LiMnPO4

(Gen 1)and Gen 2 Olivine particles

0 2 4 6 8 10

50

100

150

200

20 min

10 min

60 min

30 min

12 min

7.5 min

6 min

Dis

char

ge c

apac

ity /

mAh

g-1

Rates of discharge C C C C C

LiNi0.5Mn0.5O2 LiMnPO4 LiNi0.33Mn0.33Co0.33O2 LiNi0.4Mn0.4Co0.2O2 LiNi0.8Co0.15Al0.05O2 Gen 2 Olivine

DSC response for different cathodes in EC-DMC/ LiPF6 Solution

180 200 220 240 260 280

0.25 W/g of cathodeexo

Hea

t flo

w

LiCo1/3

Ni1/3

Mn1/3

O2

240

ºC

239 ºC

LiNi0.8

Co0.15

Al0.05

O2

205 ºC

225 ºC

232 ºC

242 ºC

Li Ni0.5

Mn1.5

O4

Li Ni0.5

Mn0.5

O2 595 J/g

1920 J/g

1020 J/g

350 J/g

1530 J/g

500 J/g

LiCo0.2

Ni0.4

Mn0.4

O2

LiMnPO4

PRISTINE

Li0.5

MnPO4

180 200 220 240 260 280

Li0.5

Ni0.5

Mn0.5

O2

197 ºC

180 200 220 240 260 280

Li0.05

Ni0.8

Co0.15

Al0.05

O2

Li0.5

MnPO4

0.25 W/g of cathode

227 ºC1220 J/g

226 ºC1315 J/g

Li0.5

Co0.2

Ni0.4

Mn0.4

O2

850 J/g

Li0.5

Co1/3

Ni1/3

Mn1/3

O2211

ºC860 J/g

217 ºC

Li0.5

Ni0.8

Co0.15

Al0.05

O2

1810 J/g

Temperature/ ºC

SOC x=0.5 ( half delithiated)

0.5 W/g of cathode

SOC x=0.05 ( fully delithiated)

230 ºCLi0.05

Ni0.5

Mn0.5

O2

640 J/g

210 ºC820 J/g

Li0.05

Co1/3

Ni1/3

Mn1/3

O2205

ºC1160 J/g

195 ºC

550 J/g

Li0.05

MnPO4

215 ºC670 J/g Li0.05

Co0.2

Ni0.4

Mn0.4

O2

Comparison between surface active and non active cathode materials

421.

2644

8.31

479.

23

570.

05

610.

63

1437

.68

1493

.72

427.

05469.

57

510.

1453

9.13

566.

1861

6.43

742.

03

788.

41

832.

85

1057

.00

1176

.81

1242

.51

1292

.75

1406

.76

1470

.53

1495

.65

-0.11

-0.10

-0.09

-0.08

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

-0.00

0.01

0.02

0.03

0.04

0.05

Abs

orba

nce

600 800 1000 1200 1400 1600 1800 2000 Wavenumbers (cm-1)

Pristin e

7 week

LiNi0.5

Mn0.5

O2

Pronounced changes

449.

73

480.

1651

6.3056

5.76

596.

20

651.

36

723.

64790.

22

852.

99

923.

37

432.

6144

9.73

482.

0751

2.50

548.

64

598.

1061

9.02

674.

18698.

91

786.

41

852.

99

927.

17

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0.11

0.12

Abs

orba

nce

600 800 1000 1200 1400 1600 1800 2000 Wavenumbers (cm-1)

LiMnPO4

No significant changes

7 week

Pristine

Wave numbers (cm-1) Wave numbers (cm-

1)

Li2

CO3

Surface chemistry

Li [MnNiCo]O2

+ROCO2

R

LiPF6

PF5

,HF,H2

O

ROCO2

Li

ROLi

[ROCO2

]n

MFx , LiFLi[NiMnCo]O2

Nucleophilic reactions

polymerization

Other oxides

Pristine powder

Li[NiMnCo]O2Powder aged

Lix

[NiMnCo]O2Electrode charged

Cobalt 2p 2/3 Manganese 2p 2/3 Nickel 2p 2/3

XPS spectra of nano-LiNi0.5

Mn0.5

O2 particles

peak at 686 eV: LiF, MnF2

, NiF2

peaks at 855

eV

and at 861.3 eV

: formation of surface species containing Ni of higher

oxidation state than 2+.

peak at 529.7 eV: nickel (III) oxide and manganese oxides.

a satellite peak at 531.7 eV: organic species with carbonyl groups

Ageing insolution

Changes in surfacechemistry and passivation

NiNi

Oxygen

FF

Oxygen

Pristine Aged at 600C

Surface chemistry

Nano-LiNi0.5

Mn0.5

O2

EC-DMC (1:2)/1.5 M LiPF6

Pristin

e

aged at 600C

Abs

orba

nce

Wavenumbers

(cm-1)

Li2

CO3 Li2

CO3

Ni –

OMn – O

Lix

PFyPoly-

carbonate

P –

F

OC

O O C Oυ −

511

573

869

1086

1437

1493

0.0

0.5

561

725780

847

903

1086

1194

1313

1407

1638

1776

1806

0.0

0.5

716

776

89297

4

1071

1160

1220

1392

1422

1478

1552

1772

1798

1862

1959

0.0

0.5

1.0

1.5

500 1000 1500 2000

FTIR spectroscopydeciphers the surface chemistry

Solution spectrum

Summary: Main Demonstrations1. Ionic liquids can work well with all relevant electrodes materials. The anodes passivation can be controlled by additives.2. LiNi0.5

Mn1.5

O4

, LiNi0.5

Mn0.5

O2

and Li[NiMnCo]O2 nano- materials can be apparently chemically stable in standard

electrolyte solutions, even at high temperatures.3.These materials develop unique surface chemistry in standard solutions that leads to their efficient passivation.4. A maximal practical capacity up to 200 mAh/g can be from both LiNi0.5

Mn0.5

O2

and LiNi0.8

Co0.15

Al0.05

O2

.The former one is a slow material.5. The fastest material is LiNi0.33

Mn0.33

Co0.33

O2 however the practical capacity is around 160 mAh/g .6. LiMnPO4

produced by HPL is the least surface reactive of all the cathode materials studied, what is well expressed in very good cycleability. Its rate capability is better than that of LiNi0.5

Mn0.5

O2

and LiNi0.8

Co0.15

Al0.05

O2