Thermodynamic aspect of sulfur, polysulfide anion and lithium polysulfide: plausible reaction path during discharge of lithium-sulfur battery

Seiji Tsuzuki, Tomoaki Kaneko, Keitaro Sodeyama, Yasuhiro Umebayashi, Wataru Shinoda, Shiro Seki, Kazuhide Ueno, Kaoru Dokko, Masayoshi Watanabe

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The elucidation of elemental redox reactions of sulfur is important for improving the performance of lithium-sulfur batteries. The energies of stable structures of Sn, Sn˙, Sn2−, [LiSn]and Li2Sn(n= 1-8) were calculated at the CCSD(T)/cc-pVTZ//MP3/cc-pVDZ level. The heats of reduction reactions of S8and Li2Snwith Li in the solid phase were estimated from the calculated energies and sublimation energies. The estimated heats of the redox reactions show that there are several redox reactions with nearly identical heats of reaction, suggesting that several reactions can proceed simultaneously at the same discharge voltage, although the discharging process was often explained by stepwise reduction reactions. The reduction reaction for the formation of Li2Sn(n= 2-6 and 8) from S8normalized as a one electron reaction is more exothermic than that for the formation of Li2S directly from S8, while the reduction reactions for the formation of Li2S from Li2Snare slightly less exothermic than that for the formation of Li2S directly from S8. If the reduction reactions with large exotherm occur first, these results suggest that the reduction reactions forming Li2Sn(n = 2-6 and 8) from S8occur first, then Li2S is formed, and therefore, a two-step discharge-curve is observed.

Original languageEnglish
Pages (from-to)6832-6840
Number of pages9
JournalPhysical Chemistry Chemical Physics
Volume23
Issue number11
DOIs
Publication statusPublished - Mar 21 2021
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Fingerprint

Dive into the research topics of 'Thermodynamic aspect of sulfur, polysulfide anion and lithium polysulfide: plausible reaction path during discharge of lithium-sulfur battery'. Together they form a unique fingerprint.

Cite this