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STUDY OF HIGH ENERGY
CATHODE MATERIALS : LI-RICH
MATERIALS
Jean-François Colin, A. Boulineau, L. Simonin, D. Peralta, C. Bourbon,
F. Fabre
CEA LITEN DEHT | October 28th, 2014
2
LiFePO4
LiMn2O4
Energy Density
above 250 Wh.kg-1 (graphite negative electrode)
Market
NCA, NMC
Instability
of the
electrolyte
Li1+xM1-xO2 NCA, NMC
LiNiPO4
LiCoPO4
Li2CoPO4F
Li2CoSiO4
LiMn1.5Ni0.5 O4
Voltage
Capacity
LiCoO2
MATERIALS FOR POSITIVE ELECTRODE
Li2MnSiO4
3
Main Issues to be solved :
Structural mechanism understanding -> O2 in red-ox reactions ? 1st high irreversible specific capacity
Gaz generation issue during 1st cycles
Voltage decay upon cycling
Thermal stability & power perfs improvement
Interests :
Li1+xM1-xO2 (0<x<1/3 ; M = Mn, Ni,…)
High specific capacity > 250mAh/g (vs. 180mAh/g for NMC)
High energy applications > 250-300Wh/kg
Low cost materials
3.4
3.5
3.6
3.7
3.8
3.9
4
0
50
100
150
200
250
300
0 10 20 30
Poten
tial (V)
Cap
acit
y (m
Ah
/g)
Cycle number
Charge capacity
discharge capacity
Potential
- 4 %
- 20 %
- 4,4 %
- 0,3% / cycle
- 0,1% / cycle
STRATEGY 2 : INCREASE CAPACITY :
LI-RICH MATERIALS
4
LI-RICH MATERIALS SOLID STATE SYNTHESIS
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Ca
pa
cit
é s
pé
cif
iqu
e / m
Ah
.g-1
Nombre de cycles
300 nm
500 nm
400 nm
600 nm
Synthesis from carbonate precursors
Optimisation carried on thermal treatment
parameters :
Optimum found at 300-400nm
But still suffers from low taped density :
d=1.1 g/cm 3 Low energy density
5
Multiparameters synthesis : pH, stirring speed,
solutions flow, T° , duration
Use of a Design Of Experiment
LI-RICH MATERIALS LIQUID SYNTHESIS
6
Enhanced performances :
C : 250 mAh/g
d= 1.6g/cm 3
Spherical particles
LI-RICH MATERIALS LIQUID SYNTHESIS
7
LI-RICH MATERIALS LIQUID SYNTHESIS
Pilot scale production : 1kg batch
8
Li-rich lamellar oxides : structural study
Li1+xM1-xO2 : M : Co, Ni, Mn Li1.2Ni2+0.2Mn4+
0.6O2 = Li(Li0.2Ni2+0.2Mn4+
0.6)O2
Can also be seen as 0.5 Li2MnO3 + 0.5 LiMn0.5Ni0.5O2
Li2MnO3
LiMn0.5Ni0.5O2
Li1.2Ni2+0.2Mn4+
0.6O2
R3 m
C2/m
OR
?
9
COMPOSITE OR SOLID SOLUTION?
Li1+xM1-xO2 : M : Co, Ni, Mn Li1.2Ni2+0.2Mn4+
0.6O2 = Li(Li0.2Ni2+0.2Mn4+
0.6)O2
Can be also seen as 0.5 Li2MnO3 + 0.5 LiMn0.5Ni0.5O2
10
COMPOSITE OR SOLID SOLUTION?
HAADF-
STEM
Nanobeam electron diffraction
Succession of domains separated by
stacking faults
Same structure in all domains but 3
different orientation (±60°)
11
COMPOSITE OR SOLID SOLUTION?
HAADF-
STEM
Bragg filter
Variation of contrast variation of chemical composition :
Bright region : TM slabs, Dark region Li1/3TM2/3
Bragg filter on C2/m spots increase the contrast
45% TM / 55% Li1/3TM2/3
COMPOSITE
12
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2
Vo
lta
ge
/
V v
s.
Li+
/Li
x in LixMn
0.61Ni
0.18Mg
0.01O
2
Structural evolution of Li-rich lamellar oxides during
cycling
1.1 Li could extracted with a reversibility on 0.8Li
New electrochemical profil : a plateau at 4.6V vs Li+/Li
Classical answer
of a lamellar oxide New phenomenon
Possible concomitant oxidation of O2- and Li extraction
What impact on structure? In situ XRD and XAS study on first cycle
13
EXPERIMENTAL SETUP
Measurement in pouch cell
X-ray diffraction : First 1.5 cycle BM20 (ESRF) 25keV (0.496Å) Image plate detector Mar 345 3 min/diffractogramm
XAS : First charge BM30B (ESRF) Ni- and Mn-edge
XANES EXAFS
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2
Vo
lta
ge
/
V v
s.
Li+
/Li
x in LixMn
0.61Ni
0.18Mg
0.01O
2
14
X-RAY DIFFRACTION
Refinement of cell parameters Space group R-3m :
a and b represent layers dimensions c represents the interslab dimension
c/3 a,b
15
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2
Vo
lta
ge /
V v
s. L
i+/L
i
x in LixMn
0.61Ni
0.18Mg
0.01O
2
2.84
2.86
2.88
1st charge
a / A
ng
str
om
14.27
14.33
14.4
1st charge
c / A
ng
str
om1st charge
For x>0.9 a decreases : M oxidizes
decreasing of M-O bond
length
c increases : decrease of
screening effect of Li
Solid solution: Classical
answer of lamellar oxide
For 0.9<x<0.1 No evolution of the cell
parameters
Biphasic process?? But no
new reflexion observable
X-RAY DIFFRACTION
16
EXISTENCE OF THE SPINEL PHASE
TEM Microscopy study after 1st charge
Apparition of a spinel phase at the surface of the particle (111)s=(003)l
Li column
TM column
Li and Mn column
“additional” TM column
17 CEA | November, 6th 2012
1st discharge
a comes back to starting value c remains much higher No reversibility with 1st charge
X-RAY DIFFRACTION
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2
Vo
lta
ge /
V v
s.
Li+
/Li
x in LixMn
0.61Ni
0.18Mg
0.01O
2
2.84
2.86
2.881st discharge
1st charge
a / A
ng
str
om
14.27
14.33
14.4
1st discharge
1st charge
c / A
ng
str
om
18
1st discharge
a comes back to starting value c remains much higher No reversibility with 1st charge
2nd charge
Reversibility of the process occuring during 1st discharge
Creation of a new
structure during the first charge that is then reversibly cycled
X-RAY DIFFRACTION
2
2.5
3
3.5
4
4.5
5
0 0.2 0.4 0.6 0.8 1 1.2
Vo
lta
ge /
V v
s. L
i+/L
i
x in LixMn
0.61Ni
0.18Mg
0.01O
2
2.84
2.86
2.88 2nd charge
1st discharge
1st charge
a / A
ng
str
om
14.27
14.33
14.4
2nd charge
1st discharge
1st charge
c / A
ng
str
om
19
VOLTAGE FADING : PROBLEMATIC
3.4
3.5
3.6
3.7
3.8
3.9
4
0
50
100
150
200
250
300
0 10 20 30
Po
ten
tial (V
)
Ca
pa
city
(m
Ah
/g)
Cycle number
Charge capacity
discharge capacity
Potential
- 4 %
- 20 %
- 4,4 %
- 0,3% / cycle
- 0,1% / cycle
Energy = Capacity * Potential Voltage decay = Energy fading
Battery Management System : The potential is not a reflect of the state of charge anymore : impossibility to build a efficient BMS
No possible commercialization
20
VOLTAGE FADING STUDY
2 cells are cycled following : - 50 cycles at C/10 (slow rate) - 1 cycles at C/10 + 48 cycles at C/2
(“high” rate) + 1 cycle at C/10 Voltage fading observed for both Disappearing of Li/Mn ordering Less impact for high rate (kinetically limited phenomena)
21
STEM-EELS experiments - chemical mapping
Pristine material 1 cycle @ C/10
VOLTAGE FADING STUDY
Chemical analysis with atomic column resotultion Homogeneous composition with expected Mn/Ni ratio Apparition of spinel phase without change of composition
22
50 cycles @ C/2 50 cycles @ C/10
Evolution of composition : Ni Enrichment of surface Stronger evolution for slow rate No growth of spinel domain Voltage decay seems to be linked more to cation migration than spinel growth
VOLTAGE FADING STUDY
23
CATIONIC MIGRATION
After one charge
No TM cation in interslab in the bulk
24
After 50 cycles
Disorder appears in the bulk with TM cation in the interslab
CATIONIC MIGRATION
25
VOLTAGE FADING : ELECTROCHEMISTRY
1 µm
Voltage fading : growth of a low potential electrochemical process Is there a link with the other electrochemical processes
26
CYCLES 2 - 13
CYCLE 1
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
CYCLE 14
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
-200
-100
0
100
200
Partial cycling
3.55V - 4.8 V
dq/d
V(m
A.h
.g-1
.V-1
)
-200
-100
0
100
200
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
dq/d
V(m
A.h
.g-1
.V-1
)
2.5 3.0 3.5 4.0 4.5
-200
-100
0
100
200
Voltage (V)
dq/d
V(m
A.h
.g-1
.V-1
)
Partial cycling
2.5V - 4.15 V
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
2.5 3.0 3.5 4.0 4.5
Voltage (V)
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
Cycles 2 - 13
cycle 2
cycle 3
cycle 4
cycle 5
cycle 6
cycle 7
cycle 8
cycle 9
cycle 10
cycle 11
cycle 12
cycle 13
Full cycling
2.5 3.0 3.5 4.0 4.5
Cycles 14
Voltage (V)
Cycle 1
4.8 V – 2.5 V 4.8 V – 2.5 V 4.8 V – 2.5 V
4.8 V – 2.5 V
4.8 V – 2.5 V4.8 V – 2.5 V4.8 V – 2.5 V
4.8 V – 3.55 V 4.15 V – 2.5 V
Partial cycling 1
Partial cycling 1
Partial cycling 1
Partial cycling 2
Partial cycling 2
Partial cycling 2
Full cycling
Full cycling
Full cycling
dq
/dV
(mA
.h.g
-1.V
-1)
dq
/dV
(mA
.h.g
-1.V
-1)
dq
/dV
(mA
.h.g
-1.V
-1)
VOLTAGE FADING : ELECTROCHEMISTRY
Use of reduced voltage window to deconvolute effect of different electrochemical processes on “ageing”
27
2.5 3.0 3.5 4.0 4.5 5.0
-300
-200
-100
0
100
200
dq/d
V(m
A.h
.g-1
.V-1
)
Voltage (V)
Full cycling - cycle 2
Full cycling - cycle 14
Cycle 14 after 12 partial cycles (4.8V 3.55V)
2.5 3.0 3.5 4.0 4.5 5.0
-300
-200
-100
0
100
200
dq/d
V(m
A.h
.g-1
.V-1
)
Voltage (V)
Full cycling - cycle 2
Full cycling - cycle 14
Cycle 14 after 12 partial cycles (4.15V 2.5V)
a b
dq
/dV
(mA
.h.g
-1.V
-1)
dq
/dV
(mA
.h.g
-1.V
-1)
VOLTAGE FADING : ELECTROCHEMISTRY
Similar ageing as full
cycling No ageing
Ageing is due to the high potential electrochemical process Anionic network participation to electrochemistry destabilize the cationic network TM migration
28
2.5 3.0 3.5 4.0 4.5 5.0
-200
-100
0
100
200
dq/d
V(m
A.h
.g-1
.V-1
)
Voltage (V)
cycle 12 full cycling2.5 to 4.8 V
cycles 3 to 12 partial cycling2.5 to 4.15 V
cycles 3 to 12 partial cycling4.15 to 4.5 V
dq/d
V(m
A.h
.g-1
.V-1
)
VOLTAGE FADING : ELECTROCHEMISTRY
29
VOLTAGE FADING : OPTIMISED PROTOCOL
0 10 20 30 40 500
20
40
60
80
100
120
140
160
180
200
220
Partial cycling
Full cycling
specif
ic c
apacit
y (
mA
h/g
)
cycle index0 10 20 30 40 50
3.50
3.55
3.60
3.65
3.70
Partial cycling
Full cycling
pote
nti
al
(V)
cycle index
a b
Switch the uppervoltage limit from
4.8 V to 4.15 V
Switch the uppervoltage limit from
4.8 V to 4.15 V
Using a reduced voltage window allow to stabilize potential Few conditionning cycle in full voltage window is necessary to get capacity Still a trade-off between stability and capacity
30
PERSPECTIVES
0
50
100
150
200
250
300
0 10 20 30 40
Cap
acit
y (m
Ah
/g)
Cycle index
0
10
20
30
Irre
vers
ibile
cap
acit
y (%
) Li1,2Ni0,2Mn0,6O2
Coating A
Coating B
Coating C
Coating strategies: - Increase the capacity of material - Decrease irreversible capacity - No effect on voltage fading
Doping strategies: - Prevent cationic migration by stabilizing the structure
- Negative impact on lithium diffusion?
31
CONCLUSIONS
Production of Li-Rich materials with high capacities via 2 way of synthesis - Solid state synthesis - Coprecipitation (also at pilot scale)
Complex lithiation-delitiation of Li-Rich material have been studied
- During first charge :
- creation of a spinel phase and irreversible change of layered oxide structure (oxygen oxidation)
- During next cycles :
- If cycled at high potential : Cationic migration provoked by the destabilisation of the oxygen network : voltage decay
- If cycled at low potential : no voltage decay but limited capacity
Jean-François Colin
DEHT/LITEN
Laboratoire des Composants pour Batteries
04 38 78 34 91
THANK YOU!
