Towards Silicon Anodes for Next-Generation Lithium Ion Batteries: A ...
Towards Silicon Anodes for Next-Generation Lithium Ion Batteries: A Comparative Performance Study of Various Polymer Binders and Silicon Nanopowders Christoph Erk,†,‡,* Torsten Brezesinski,† Heino Sommer,†,‡ Reinhard Schneider,# and Jürgen Janek†,+,* †
Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz
1, 76344 Eggenstein-Leopoldshafen, Germany, and ‡BASF SE, 67056 Ludwigshafen, Germany, and #Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstr. 7, 76131 Karlsruhe, Germany, and +Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
*E-mail: [email protected]; [email protected].
1
Figure S1. Top view SEM images of electrodes comprising Si-50 (Alfa Aesar) silicon nanopowder and various binders. From these images, it can be clearly seen that the morphology of the different electrode tapes is very similar.
2
Figure S2. Lithiation capacity as a function of cycle number for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and PEO polymer binder.
Table S1. Summarized cycling data for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and various binders.
Binder
1st cycle lithiation capacity (mAh/gSi) FEC
EC
1st cycle irreversible capacity (%)
Capacity retention after cycle no. 5 (%)
Capacity retention after cycle no. 33 (%)
Capacity retention after cycle no. 42 (%)
Capacity retention after cycle no. 59 (%)
FEC
EC
FE C
EC
FE C
EC
F E C
EC
FE C
EC
AA (medium visc.)
3790 3660
19
13
95
95
68
49
66
46
62
40
PAA (450.000)
3790 3780
13
11
92
91
80
61
75
56
73
43
PVA (Selvol 425)
4180 4110
14
10
83
83
68
53
64
46
59
33
CMC
3650 3780
24
11
77
82
47
31
43
28
43
23
3
(250.000) PVDF (Kynar HSV 900)
4090 4060
43
29
92
92
70
51
68
44
52
38
Figure S3. 1st cycle discharge profiles in the voltage range between 1.8 V and 0.1 V vs. Li/Li+ for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and various binders. (a) ECbased electrolyte. (b) FEC-based electrolyte.
4
Figure S4. Typical XRD patterns for Si-50 (Alfa Aesar) and Si-100 (Aldrich) silicon nanopowders. Debye Scherrer analysis provides average crystallite sizes of 47 nm and 78 nm, respectively.
5
Figure S5. XPS detail spectra (black curves) of Si-50 (Alfa Aesar; a, b) and Si-100 (Aldrich; c, d) silicon nanopowders. (a, c) Si 2p spectra. (b, d) O 1s spectra. Blue, red and orange curves are fits to the data while green curves correspond to the sum of the peak fits. The Shirley method was applied to subtract backgrounds.
6
Figure S6. N2-adsorption/desorption isotherms for Si-50 (Alfa Aesar; a) and Si-100 (Aldrich; b) silicon nanopowders. From these data, we obtain BET surface areas of 32 m2/g and 35 m2/g for Si-50 and Si-100, respectively.
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Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz
1, 76344 Eggenstein-Leopoldshafen, Germany, and ‡BASF SE, 67056 Ludwigshafen, Germany, and #Laboratory for Electron Microscopy, Karlsruhe Institute of Technology, Engesserstr. 7, 76131 Karlsruhe, Germany, and +Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
*E-mail: [email protected]; [email protected].
1
Figure S1. Top view SEM images of electrodes comprising Si-50 (Alfa Aesar) silicon nanopowder and various binders. From these images, it can be clearly seen that the morphology of the different electrode tapes is very similar.
2
Figure S2. Lithiation capacity as a function of cycle number for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and PEO polymer binder.
Table S1. Summarized cycling data for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and various binders.
Binder
1st cycle lithiation capacity (mAh/gSi) FEC
EC
1st cycle irreversible capacity (%)
Capacity retention after cycle no. 5 (%)
Capacity retention after cycle no. 33 (%)
Capacity retention after cycle no. 42 (%)
Capacity retention after cycle no. 59 (%)
FEC
EC
FE C
EC
FE C
EC
F E C
EC
FE C
EC
AA (medium visc.)
3790 3660
19
13
95
95
68
49
66
46
62
40
PAA (450.000)
3790 3780
13
11
92
91
80
61
75
56
73
43
PVA (Selvol 425)
4180 4110
14
10
83
83
68
53
64
46
59
33
CMC
3650 3780
24
11
77
82
47
31
43
28
43
23
3
(250.000) PVDF (Kynar HSV 900)
4090 4060
43
29
92
92
70
51
68
44
52
38
Figure S3. 1st cycle discharge profiles in the voltage range between 1.8 V and 0.1 V vs. Li/Li+ for electrodes made from Si-50 (Alfa Aesar) silicon nanopowder and various binders. (a) ECbased electrolyte. (b) FEC-based electrolyte.
4
Figure S4. Typical XRD patterns for Si-50 (Alfa Aesar) and Si-100 (Aldrich) silicon nanopowders. Debye Scherrer analysis provides average crystallite sizes of 47 nm and 78 nm, respectively.
5
Figure S5. XPS detail spectra (black curves) of Si-50 (Alfa Aesar; a, b) and Si-100 (Aldrich; c, d) silicon nanopowders. (a, c) Si 2p spectra. (b, d) O 1s spectra. Blue, red and orange curves are fits to the data while green curves correspond to the sum of the peak fits. The Shirley method was applied to subtract backgrounds.
6
Figure S6. N2-adsorption/desorption isotherms for Si-50 (Alfa Aesar; a) and Si-100 (Aldrich; b) silicon nanopowders. From these data, we obtain BET surface areas of 32 m2/g and 35 m2/g for Si-50 and Si-100, respectively.
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