Issue 59, 2019

Diphenyl polysulfides: cathodes with excellent lithiation performance and high specific energy for LSBs

Abstract

Reversible lithium–sulfur batteries (LSBs) are considered one of the most promising next-generation energy storage systems. However, the shuttling effect of lithium polysulfide significantly weakens the electrochemical properties and the cycle life, hindering its practical application. Organo-sulfides are unique materials with low cost, profuse content and high capacity. Here, via quantum chemical calculations, we introduce a class of diphenyl polysulfides, PhSnPh (2 ≤ n ≤ 15), which are all structurally stable, confirmed by calculation of their Gibbs free energies. The theoretical specific energy of PhS15Ph is high, up to 2632 W h kg−1, exceeding that of S8. By calculating the bond dissociation energy of S–S in PhSnPh molecules, we analyze the breaking processes of the S–S bonds in each step of lithiation. The microscopic mechanism of the fast reaction kinetics of PhSnPh cathodes is explored. It is phenyl that prevents the formation of soluble long-chain polysulfide molecules (Li2S4, Li2S6, Li2S8) in the lithiation process, efficiently weakening the “shuttle effect”.

Graphical abstract: Diphenyl polysulfides: cathodes with excellent lithiation performance and high specific energy for LSBs

Supplementary files

Article information

Article type
Paper
Submitted
16 Aug 2019
Accepted
14 Oct 2019
First published
25 Oct 2019
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2019,9, 34430-34436

Diphenyl polysulfides: cathodes with excellent lithiation performance and high specific energy for LSBs

C. Wang, J. Wu, X. Li and Y. Mi, RSC Adv., 2019, 9, 34430 DOI: 10.1039/C9RA06402H

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