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A quasi-intercalation reaction for fast sulfur redox kinetics in solid-state lithium-sulfur batteries

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Solid-state lithium-sulfur (Li-S) batteries are recognized as a competitive candidate for next-generation energy storage systems due to their high energy density and safety. However, the slow redox kinetics between S...
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Supporting Information
A quasi-intercalation reaction for fast sulfur redox kinetics in solid-
state lithium-sulfur batteries
Chuang Li #, a, Qi Zhang #, a, Jinzhi Sheng #, a, Biao Chen a, b, Runhua Gao a, Zhihong
Piao a, Xiongwei Zhong a, Zhiyuan Han a, Yanfei Zhu a, Jiulin Wang c, Guangmin Zhou
*, a, Hui-Ming Cheng *, d, e
a Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School,
Tsinghua University, Shenzhen 518055, China
b School of Materials Science and Engineering, Tianjin Key Laboratory of Composite
and Functional Materials, Tianjin University, Tianjin, 300350, China
c College of Chemistry, Xinjiang University, Urumqi, 8300417 Xinjiang, China
d Faculty of Materials Science and Engineering/Institute of Technology for Carbon
Neutrality, Shenzhen Institute of Advanced Technology, Chinese Academy of Science,
Shenzhen 518055, China
e Shenyang National Laboratory for Materials Science, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China
* Corresponding authors: Guangmin Zhou (Email: guangminzhou@sz.tsinghua.
edu.cn); Hui-Ming Cheng (Email: cheng@imr.ac.cn)
# These authors were equal major contributors.
Electronic Supplementary Material (ESI) for Energy & Environmental Science.
This journal is © The Royal Society of Chemistry 2022
Figure S1. Schematic representation of the preparation of the PVDF-HFP-
in-LiFSI (1PVHF1FSI) membrane.
660 675 690
Intensity (a.u.)
Raman shift (cm-1)
1PVHF1FSI
Pure DMF
Bound DMF
Free DMF
Figure S2. Raman spectra of pure DMF and 1PVHF1FSI. The peak
positions for bound and free DMF molecules are 675.9 and 663.3 cm-1,
respectively1. There is no visible 663.3 cm-1 peak in the Raman spectra of
1PVHF1FSI, showing the solid-state property.
Figure S3. CV curves of a Li/1PVHF1FSI/Cu half-cell.
Figure S4. Charge-discharge curves of liquid SPAN at different cycles.
Figure S5. Nyquist plots of (a) liquid SPAN and (b) solid SPAN. (c) the
values of Rf (interface resistance from cathode-electrolyte interface and
lithium anode-electrolyte interface) at various cycles. The large interfacial
resistance of liquid SPAN in the first cycle is due to the native oxide layers
and the dendrite Li formation2. (d) the values of R0 (ohmic resistance from
electrolyte resistance, contact resistance between the electrode material
and the collector, etc.) at various cycles. The similar R0 values at different
cycles indicate that there is no shuttling causing electrolyte resistance in
both solid SPAN and liquid SPAN.
Figure S6. SEM images of cathodes in (a) solid SBP and (b) solid SPAN
before and after 5 cycles.
Figure S7. The configuration of a solid SPAN coin cell used for in-situ
Raman spectroscopy.
Figure S8. Proposed unstable configuration of SPAN, where the S-S bonds
break spontaneously.
Figure S9. (a) Proposed configuration of SPAN and (b) electrical
localization of DMF and SPAN through electrical localization function
calculations (the darker blue in S atom sites of solid SPAN indicate a
stronger C-S bond strength).
Figure S10. FTIR spectra of pure acetone and 1PVHF1FSI (acetone as
solvent). The typical peak position (C≡N) of pure acetone is 2252 cm-1.
There is no visible 2252 cm-1 peak in the FTIR spectra of 1PVHF1FSI
(acetone as solvent), showing the acetone was removed completely.
-9 -6 -3 0 3 6 9
(7Li) / ppm
2nd discharge
2nd Charge
Figure S11. 7Li MAS NMR spectra of the SPAN cathodes in solid SPAN
without trace DMF after the second discharge/charge.
Figure S12. Possible structures of SPAN and investigation of the origin of
irreversible capacity loss during the first discharge process in solid SPAN.
Three configurations on the left are possible structures of SPAN and the
possible reaction pathways of the first discharge process are shown. The
reaction process leading to irreversible capacity loss needs to be
thermodynamically favorable, which means that the change of Gibbs free
energy should be sufficiently negative. (a) It is favorable that two nitrogen
atoms in SPAN react with one lithium ion with a significantly negative
change in the Gibbs free energy. But one nitrogen cannot be further
connected with two lithium ions. (b) This process is reversible since the
change in Gibbs energy of this reaction is not sufficiently negative, so it
does not result in an irreversible capacity loss. (c) This process is
thermodynamically unfavorable.
Figure S13. The thermodynamically favorable discharge pathway of solid
SPAN batteries highlighted by translucent blue arrows.
Figure S14. The thermodynamically favorable discharge pathway of liquid
SPAN batteries highlighted by translucent blue arrows.
Figure S15. The bond lengths of C-S after Li storage in (a) liquid SPAN
and (b) solid SPAN.
Figure S16. Comparison of the thermal stabilities of a PP separator and
1PVHF1FSI.
Table S1. Cycling performance comparison of solid-state Li-S batteries.
Entry
Electrolyte
Cathode
Capacity
(mAh g-1)
Cycle
Temperatur
e
()
1
AQT@PEO/LiTFSI
Li2S
620/0.1C
60
60
3
2
PEO/LiTFSI
S@C
630/0.05
mA cm-2
60
55
4
3
PEO/PIM12%/LiTFSI
S
~750/0.05C
30
60
5
4
PEO/LiDFTFSI
S@C
~600/0.1C
30
70
6
Li10GeP2S12
S@pPAN
296/0.1C
150
25
7
5
Li10GeP2S12
Se0.05S0.95@pPAN
680.4/0.1C
150
25
7
6
Li3.25Ge0.25P0.75S4/PEO/
Pyr1,4TFSI
SPAN
588/0.1C
50
60
8
7
1PVHF1FSI
SPAN
897.4/0.2C
100
25
This
work
Reference
1. Fujii, K.; Wakamatsu, H.; Todorov, Y.; Yoshimoto, N.; Morita, M., Structural and
electrochemical properties of Li ion solvation complexes in the salt-concentrated electrolytes using an
aprotic donor solvent, N,N-dimethylformamide. The Journal of Physical Chemistry C 2016, 120 (31),
17196-17204.
2. Lin, D.; Liu, Y.; Liang, Z.; Lee, H.-W.; Sun, J.; Wang, H.; Yan, K.; Xie, J.; Cui, Y.,
Layered reduced graphene oxide with nanoscale interlayer gaps as a stable host for lithium metal anodes.
Nature Nanotechnology 2016, 11 (7), 626-632.
3. Gao, X.; Zheng, X.; Tsao, Y.; Zhang, P.; Xiao, X.; Ye, Y.; Li, J.; Yang, Y.; Xu, R.;
Bao, Z.; Cui, Y., All-solid-state lithium–sulfur batteries enhanced by redox mediators. Journal of the
American Chemical Society 2021, 143 (43), 18188-18195.
4. Fang, R.; Xu, H.; Xu, B.; Li, X.; Li, Y.; Goodenough, J. B., Reaction mechanism optimization
of solid-state Li–S batteries with a PEO-based electrolyte. Advanced Functional Materials 2021, 31 (2),
2001812.
5. Ji, Y.; Yang, K.; Liu, M.; Chen, S.; Liu, X.; Yang, B.; Wang, Z.; Huang, W.; Song,
Z.; Xue, S.; Fu, Y.; Yang, L.; Miller, T. S.; Pan, F., PIM-1 as a multifunctional framework to
enable high-performance solid-state lithium–sulfur batteries. Advanced Functional Materials 2021, 31
(47), 2104830.
6. Zhang, H.; Oteo, U.; Judez, X.; Eshetu, G. G.; Martinez-Ibañez, M.; Carrasco, J.; Li, C.;
Armand, M., Designer anion enabling solid-state lithium-sulfur batteries. Joule 2019, 3 (7), 1689-1702.
7. Zhang, Y.; Sun, Y.; Peng, L.; Yang, J.; Jia, H.; Zhang, Z.; Shan, B.; Xie, J., Se as eutectic
accelerator in sulfurized polyacrylonitrile for high performance all-solid-state lithium-sulfur battery.
Energy Storage Materials 2019, 21, 287-296.
8. Li, M.; Frerichs, J. E.; Kolek, M.; Sun, W.; Zhou, D.; Huang, C. J.; Hwang, B. J.; Hansen,
M. R.; Winter, M.; Bieker, P., Solid-state lithium–sulfur battery enabled by thio-LiSICON/polymer
composite electrolyte and sulfurized polyacrylonitrile cathode. Advanced Functional Materials 2020, 30
(14), 1910123.
... Li et al. 111 designed a PVDF-HFP-in-lithium bis (fluorosulfonyl)imide (PVDF-HFP-in-LiFSI) polymer-insalt SPE in recent work. The residual N, Ndimethylformamide (DMF) solvent provides a new intercalation-like reaction mechanism in SPAN cathode, from which strong interaction between high dielectric constant DMF and Li þ weakened the electrophilicity of Li þ , the C−S bond in SPAN is protected from the attacking of Li þ Therefore, SPAN exhibited better conductivity and smaller volume change owing to the enhanced C−S bonding. ...
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