In Situ X-ray Absorption Spectroscopic Investigation of the Capacity Degradation Mechanism in Mg/S Batteries

Yan Xu, Yifan Ye, Shuyang Zhao, Jun Feng, Jia Li, Hao Chen, Ankun Yang, Feifei Shi, Lujie Jia, Yang Wu, Xiaoyun Yu, Per Anders Glans-Suzuki, Yi Cui, Jinghua Guo, Yuegang Zhang

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The Mg/S battery is attractive because of its high theoretical energy density and the abundance of Mg and S on the earth. However, its development is hindered by the lack of understanding to the underlying electrochemical reaction mechanism of its charge-discharge processes. Here, using a unique in situ X-ray absorption spectroscopic tool, we systematically study the reaction pathways of the Mg/S cells in Mg(HMDS)2-AlCl3 electrolyte. We find that the capacity degradation is mainly due to the formation of irreversible discharge products, such as MgS and Mg3S8, through a direct electrochemical deposition or a chemical disproportionation of intermediate polysulfide. In light of the fundamental understanding, we propose to use TiS2 as a catalyst to activate the irreversible reaction of low-order MgSx and MgS, which results in an increased discharging capacity up to 900 mAh·g-1 and a longer cycling life.

Original languageEnglish (US)
Pages (from-to)2928-2934
Number of pages7
JournalNano letters
Volume19
Issue number5
DOIs
StatePublished - May 8 2019

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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