Electrochemically synthesized liquid-sulfur/sulfide composite materials for high-rate magnesium battery cathodes

Kohei Shimokawa, Takuya Furuhashi, Tomoya Kawaguchi, Won Young Park, Takeshi Wada, Hajime Matsumoto, Hidemi Kato, Tetsu Ichitsubo

Research output: Contribution to journalArticlepeer-review

Abstract

Mg/S batteries are some of the most promising rechargeable batteries owing to their high theoretical energy density. Their development is, however, hindered by (i) low electronic conductivity of S, (ii) sluggish Mg2+diffusion in solid Mg-S compounds formed by discharge, and (iii) dissolubility of polysulfides into electrolytes. To address these problems, we propose liquid-S/sulfide composite cathode materials in combination with an ionic liquid electrolyte at intermediate temperatures (∼150 °C). The composite structure is spontaneously fabricated by electrochemically oxidizing metal sulfides, yielding liquid S embedded in a porous metal-sulfide conductive frame. This concept is demonstrated by a S/FeS2composite cathode, which shows a significantly high-rate capability of,e.g., 1246 mA g−1(S)with a capacity of ∼900 mA h g−1(S). In addition, non-equilibrium liquid S formed by fast charging results in an unexpected higher discharge potential. This work provides a new strategy to design S-based cathodes for achieving high-rate multivalent rechargeable batteries.

Original languageEnglish
Pages (from-to)16585-16593
Number of pages9
JournalJournal of Materials Chemistry A
Volume9
Issue number30
DOIs
Publication statusPublished - 2021 Aug 14

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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