18. GDS Anwendertreffen
26.09.2019, Freiberg
Karsten Richter, Thomas Waldmann, Michaela Memm, Michael Kasper,
Peter Axmann, Margret Wohlfahrt-Mehrens
Zentrum für Sonnenenergie- und Wasserstoff-Forschung
Baden-Württemberg (ZSW)
Aging mechanisms in Lithium ion batteries revealed
by GD-OES depth profiling
- 2 -
Working principal and aging mechanism
Mechanism related to
Li deposition
SEI
Li
Li
Li
Li
Li
Li
Li Li Li
Anode
CathodeAmbient charging
conditions
Low currents /
room temp.
SEI
Li
LiLi
Li
Li
Li
Li
Li
Li
Challenging
charging conditions
high currents /
low temp.
[1] T. Waldmann, B.-I. Hogg, M. Wohlfahrt-Mehrens, J. Power Sources 2018, 384, 107–124.
- 3 -
Li metal deposition – Spatially resolved
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
depth / µm
Li, O
, P
/ w
t.-%
O
0
20
40
60
80
100
C / w
t.-%
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
O
depth / µm
Li, O
, P
/ w
t.-%
0
20
40
60
80
100
C / w
t.-%
- dominant
dendritic structure
Li metal
deposition
- inhomogeneous
and small dendritic
structures visible
[2] T. Waldmann, J. B. Quinn, K. Richter, M. Kasper, A. Tost, A. Klein, M. Wohlfahrt-Mehrens, J. Electrochem. Soc. 2017, 164, A3154–A3162.
SEM
CT
- 4 -
Li metal deposition – Effect of resting time
0 2 4 6 80
5
10
15
20
25
30
35
40
P
Li
O
depth / µm
Li, O
, P
/ w
t-%
C
0
20
40
60
80
100
C / w
t.-%
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
depth / µm
Li, O
, P
/ w
t.-%
O
0
20
40
60
80
100
C / w
t.-%
8 h
GD
-OE
SS
EM
- after cell operation:
dominant Li metal
deposition and high
surface concentration of Li
- after resting broad and
flat Li distribution
GD-OES reveals
reintercalation of Li
No dendritic structure
visible
[2] T. Waldmann, J. B. Quinn, K. Richter, M. Kasper, A. Tost, A. Klein, M. Wohlfahrt-Mehrens, J. Electrochem. Soc. 2017, 164, A3154–A3162.
rest
- 5 -
Aging mechanism – Effect of operating temperature
0 2 4 6 80
5
10
15
20
25
30
35
40
PLi
O
depth / µm
Li, O
, P
/ w
t-%
C
0
20
40
60
80
100
C / w
t.-%
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
depth / µm
Li, O
, P
/ w
t.-%
O
0
20
40
60
80
100
C / w
t.-%
0 2 4 6 80
5
10
15
20
25
30
35
40
P
Li O
C
depth / µm
Li, O
, P
/ w
t-%
0
20
40
60
80
100
C /
wt.-%
Fresh cell: initial SEICycling at 0 °C: Li metal
covers anode Surface
Cycling at 45 °C: Un-
ceasing film formation (e.g.
Li2O, Li2CO3)
[2] T. Waldmann, J. B. Quinn, K. Richter, M. Kasper, A. Tost, A. Klein, M. Wohlfahrt-Mehrens, J. Electrochem. Soc. 2017, 164, A3154–A3162.
Graphite, LiC6: 372 mAh g-1
Silicon, Li15Si4: 3579 mAh g-1
- 6 -
Increasing demand for energy
lithiation
delit
hia
tion
binder
conductive additive
passiv
atio
n
High volume expansion
- Particle cracking
- Contact loss
- Ongoing film formation and
Li+-Ion consumption
- Formation of passivation
layer and intrinsic
mechanical instability
(mixing, volume change)
- Anisotropic de-/lithiation
[3] M. N. Obrovac, L. Christensen, D. B. Le, J. R. Dahn, J. Electrochem. Soc. 2007, 154, A849. [4] M. N. Obrovac, V. L. Chevrier, Chem. Rev. 2014, 114, 11444–11502.
[5] P. Limthongkul, Y.-I. Jang, N. J. Dudney, Y.-M. Chiang, Acta Mater. 2003, 51, 1103–1113. [6] N. Delpuech, N. Dupre, P. Moreau, J.-S. Bridel, J. Gaubicher, B. Lestriez, D. Guyomard, ChemSusChem 2016, 9, 841–84
- 7 -
Si in LIB anodes – GD-OES approach
0 5 10 15 20 25 30 350
5
10
15
20
25
30
35 GD-OES
EDX
Quantified S
i (w
t.-%
)
Si in reference samples (wt.-%)0 2 4 6 8 10
0
10
20
30
40
50
60
70
80
90
100
(16.5 ± 2.5) wt.-%
(20.5 ± 1.9) wt.-%
(1.1 ± 0.1) wt.-%
(61.0 ± 0.9) wt.-%
(65.9 ± 1.5) wt.-%
Si (w
t.-%
)
depth (µm)
(99.7 ± 1.1) wt.-%
0 100 200 300 4000.0
0.1
0.2
0.3
0.4
Inte
nsity x
10
00
Si (a
.u.)
sputtering time (s)
Initial sputtering
1st interruption
2nd interruption
mean bulk intensity
0 2 4 6 80
5
10
15
20
25
P
Si
C
O
Li, O
, P
, S
i (w
t.-%
)
depth (µm)
Li20
30
40
50
60
70
80
90
100C
(w
t.-%
)
- covering 0-100 wt.-%
Si to analyse graphite
and Si dominant
composite electrodes
- unexpected Si
distribution observed
[7] K. Richter, T. Waldmann, M. Memm, M. Kasper, M. Wohlfahrt-Mehrens, J. Electrochem. Soc. 2018, 165, A3602–A3604
[8] K. Richter, T. Waldmann, M. Kasper, C. Pfeifer, M. Memm, P. Axmann, M. Wohlfahrt-Mehrens, J. Phys. Chem. C 2019, 123, 18795–18803
- 8 -
Si related aging mechanism – revealed by GD-EOS
0 2 4 6 80
5
10
15
20
25
P
Si
C
O
Li, O
, P
, S
i (w
t.-%
)
depth (µm)
Li20
30
40
50
60
70
80
90
100
C (
wt.
-%)
0 2 4 6 80
5
10
15
20
25
Li, O
, P
, S
i (w
t.-%
)
depth (µm)
Si
P
20
30
40
50
60
70
80
90
100C
(w
t.-%
)
O
C
Li
3x 60s dip washed
with DMC
- Si detectable in DMC with ICP-OES
5 SiO + 6 Li Li2O + Li4SiO4 + 4 Si
5 SiO2 + 4 Li 2 Li2Si2O5 + Si
Side reaction of active material
with electrolyte, consumes Li.
Additional film formation and
dissolution.
[7] K. Richter, T. Waldmann, M. Memm, M. Kasper, M. Wohlfahrt-Mehrens, J. Electrochem. Soc. 2018, 165, A3602–A3604
[8] K. Richter, T. Waldmann, M. Kasper, C. Pfeifer, M. Memm, P. Axmann, M. Wohlfahrt-Mehrens, J. Phys. Chem. C 2019, 123, 18795–18803
- 9 -
Si related aging mechanism – revealed by GD-EOS
0.0 0.5 1.0 1.5 2.00
5
10
15
20
25
30
35
40
Si / w
t.-%
depth / µm
Formation
50 Cy C/3 RT
50 Cy C/3 45 °C
40 Cy C/3 0 °C
0 2 4 6 8 100
5
10
15
20
25
30
35
40
Si / w
t.-%
depth / µm
Formation
50 Cy C/3 RT
50 Cy C/3 45 °C
40 Cy C/3 0 °C
0 2 4 6 8 100
5
10
15
20
25
30
35
Si / w
t.-%
depth / µm
Formation
50 Cy C/3 RT
50 Cy C/3 RT MdCh
25 Cy MdCh 25 Cy C/3 RT
0.0 0.5 1.0 1.5 2.00
5
10
15
20
25
30
35S
i / w
t.-%
depth / µm
Formation
50 Cy C/3 RT
50 Cy C/3 RT MdCh
25 Cy MdCh 25 Cy C/3 RT
- Si distribution depends on physical
and electrochemical operation
conditions
- 45 °C enhances film formation,
containing Si-rich species
- 0 °C shifts the Si distribution to
deeper levels of the electrode
- lower cut off potential increases Si
species on surface
Enhanced side reactions during
discharge
- 10 -
Conclusions
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
depth / µm
Li, O
, P
/ w
t.-%
O
0
20
40
60
80
100
C /
wt.-%
- GDOES provides spatially resolved elemental
distribution
Covering the plating behaviour over the jelly
roll
- GDOES provides information about the aging
mechanism regarding cell operation conditions
Differentiation between, e.g. Li metal
deposition or electrolyte decomposition
- GDOES can be calibrated to novel battery
materials revealing material specific aging
mechanism
Film formation and dissolution on Si/C
composite materials
0 2 4 6 80
5
10
15
20
25
30
35
40
PLi
O
depth / µm
Li, O
, P
/ w
t-%
C
0
20
40
60
80
100
C / w
t.-%
0 2 4 6 80
5
10
15
20
25
30
35
40
C
P
Li
depth / µm
Li, O
, P
/ w
t.-%
O
0
20
40
60
80
100
C /
wt.-%
0 5 10 15 20 25 30 350
5
10
15
20
25
30
35 GD-OES
EDX
Quantified S
i (w
t.-%
)
Si in reference samples (wt.-%)
0 2 4 6 80
5
10
15
20
25
P
Si
C
O
Li, O
, P
, S
i (w
t.-%
)
depth (µm)
Li20
30
40
50
60
70
80
90
100
C (
wt.
-%)
0 2 4 6 80
5
10
15
20
25
Li, O
, P
, S
i (w
t.-%
)
depth (µm)
Si
P
20
30
40
50
60
70
80
90
100
C (
wt.-%
)
O
C
Li
electrode
washing
- 11 -
Widderstall:
Solar Test Facility
-// Energy with a future
-// Zentrum für Sonnenenergie- und Wasserstoff-
Forschung Baden-Württemberg (ZSW)
Thank you for your attention!
Stuttgart:
Photovoltaics, Energy
Policy and Energy
Carriers, Central
Division Finance,
Human Resources
& Legal
Ulm:
Electrochemical Energy Technologies - Main Building & eLaB
// Energy with a future
// Zentrum für Sonnenenergie- und Wasserstoff-
Forschung Baden-Württemberg (ZSW)
Funding:
MAT4BAT – EU (n° 608931)
LIB.DE – BMWi (n° 03ET6081A)
ZSW:
Niloofar Ghanbari (now Bosch)
Thomas Waldmann
Michaela Memm
Michael Kasper
Peter Axmann
Margret Wohlfahrt-Mehrens
Spectruma:
Rüdiger Meihsner
Tatjana Leibßle
Otto Paljok
Tahir Serbet
Michael Analytis