Potassium-ion storage mechanism of MoS2-WS2-C microspheres and their excellent electrochemical properties

Jae Hun Choi, Gi Dae Park, Yun Chan Kang

Research output: Contribution to journalArticlepeer-review

Abstract

Potassium-ion batteries are receiving increasing interest as a new type of secondary batteries because of their low redox potentials. In particular, two-dimensional transition metal dichalcogenides are being widely studied because they possess a layered structure with a large interlayer distance; these structural characteristics are favorable for hosting potassium-ions. However, capacity decay occurs and the intercalation of potassium-ions is hindered due to the huge volume expansion during the cycling process. Here, MoS2-WS2-C microspheres containing highly porous structure and heterogeneous interfaces are synthesized through facile spray pyrolysis. Benefiting from the unique structure and hetero-interfaces, the composite microspheres exhibit stable cycle performance and an outstanding rate performance. Meanwhile, a reversible capacity of 350 mA h g−1 is achieved after 100 cycles at the current density of 100 mA g−1, and even at the high current density of 5.0 A g−1, it maintains a capacity of 176 mA h g−1. The potassium-ion storage mechanism of MoS2-WS2-C microspheres is also systematically explored via ex-situ transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). With the advantages of highly reversible intercalation from WS2 and high specific capacity of conversion from MoS2, the MoS2-WS2-C microspheres achieve high rate performance and specific capacity.

Original languageEnglish
Article number127278
JournalChemical Engineering Journal
DOIs
Publication statusAccepted/In press - 2020

Keywords

  • Molybdenum sulfide
  • Potassium-ion batteries
  • Spray pyrolysis
  • Transition metal dichalcogenide
  • Tungsten sulfide

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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