Preparation of yolk-shell and filled Co9S8 microspheres and comparison of their electrochemical properties

You Na Ko, Seung Ho Choi, Seung Bin Park, Yun Chan Kang

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)

Abstract

In this study, we report the first preparation of phase-pure Co 9S8 yolk-shell microspheres in a facile two-step process and their improved electrochemical properties. Yolk-shell Co3O 4 precursor microspheres are initially obtained by spray pyrolysis and are subsequently transformed into Co9S8 yolk-shell microspheres by simple sulfidation in the presence of thiourea as a sulfur source at 350 °C under a reducing atmosphere. For comparison, filled Co 9S8 microspheres were also prepared using the same procedure but in the absence of sucrose during the spray pyrolysis. The prepared yolk-shell Co9S8 microspheres exhibited a Brunauer-Emmett-Teller (BET) specific surface area of 18 m2 g -1 with a mean pore size of 16 nm. The yolk-shell Co 9S8 microspheres have initial discharge and charge capacities of 1008 and 767 mA h g-1 at a current density of 1000 mA g-1, respectively, while the filled Co9S8 microspheres have initial discharge and charge capacities of 838 and 638 mA h g-1, respectively. After 100 cycles, the discharge capacities of the yolk-shell and filled microspheres are 634 and 434 mA h g-1, respectively, and the corresponding capacity retentions after the first cycle are 82 % and 66 %.

Original languageEnglish
Pages (from-to)572-576
Number of pages5
JournalChemistry - An Asian Journal
Volume9
Issue number2
DOIs
Publication statusPublished - 2014 Feb
Externally publishedYes

Keywords

  • cobalt sulfide
  • lithium-ion batteries
  • mesoporous materials
  • nanostructures
  • spray pyrolysis
  • sulfur

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry
  • Organic Chemistry

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