Role of Cu in Mo6S8 and Cu mixture cathodes for magnesium ion batteries

Seung Hyun Choi, Jeom Soo Kim, Sang Gil Woo, Woosuk Cho, Sun Yong Choi, Jungkyu Choi, Kyu Tae Lee, Min Sik Park, Young Jun Kim

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

The reversible capacity of Chevrel Mo6S8 cathode can be increased by the simple addition of the Cu metal to Mo6S8 electrodes. However, the exact reaction mechanism of the additional reversible capacity for the Mo6S8 and Cu mixture cathode has not been clearly understood yet. To clarify this unusual behavior, we synthesize a novel Cu nanoparticle/graphene composite for the preparation of the mixture electrode. We thoroughly investigate the electrochemical behaviors of the Mo6S8 and Cu mixture cathode with the relevant structural verifications during Mg2+ insertion and extraction. The in situ formation of CuxMo6S8 is observed, indicating the spontaneous electrochemical insertion of Cu to the Mo6S8 host from the Cu nanoparticle/graphene composite. The reversible electrochemical replacement reaction of Cu in the Mo6S8 structure is clarified with the direct evidence for the solid state Cu deposition/dissolution at the surface of Mo6S8 particles. Moreover, the Mo6S8 and Cu mixture cathode improves the rate capability compared to the pristine. We believe that our finding will contribute to understanding the origin of the additional capacity of the Mo6S8 cathode arising from Cu addition and improve the electrochemical performance of the Mo6S8 cathode for rechargeable Mg batteries.

Original languageEnglish
Pages (from-to)7016-7024
Number of pages9
JournalACS Applied Materials and Interfaces
Volume7
Issue number12
DOIs
Publication statusPublished - 2015 Apr 1

Keywords

  • Chevrel MoS
  • Cu nanoparticle/graphene composite
  • Mg batteries
  • cathode
  • electrochemistry

ASJC Scopus subject areas

  • Materials Science(all)

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