Capacitive properties of reduced graphene oxide microspheres with uniformly dispersed nickel sulfide nanocrystals prepared by spray pyrolysis

Su Min Lee, You Na Ko, Seung Ho Choi, Jong Hwa Kim, Yun Chan Kang

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Nickel sulfide-reduced graphene oxide (RGO) composite powders with spherical shapes are prepared by a one-pot spray pyrolysis process. The optimum mole ratio of nickel nitrate and thiourea to obtain nickel sulfide-RGO composite powders with high initial capacities and good cycling performance is 1:8. The bare nickel sulfide and nickel sulfide-RGO composite powders prepared directly by spray pyrolysis have mixed crystal structures of hexagonal α-NiS and cubic Ni 3 S 4 phases. The bare nickel sulfide powders are prepared from the spray solution without graphene oxide sheets. The nickel sulfide-RGO composite powders have sharp mesopores approximately 3.5 nm in size. The discharge capacities of the nickel sulfide-RGO composite powders for the 1st and 200th cycles at a current density of 1000 mA g -1 are 1046 and 614 mA h g -1 , respectively, and the corresponding capacity retention measured from the second cycle is 89%. However, the discharge capacities of the bare nickel sulfide powders for the 1st and 200th cycles at a current density of 1000 mA g -1 are 832 and 16 mA h g -1 , respectively. The electrochemical impedance spectroscopy (EIS) measurements reveal the high structural stability of the nickel sulfide-RGO composite powders during cycling.

Original languageEnglish
Pages (from-to)287-293
Number of pages7
JournalElectrochimica Acta
Volume167
DOIs
Publication statusPublished - 2015 Jun 10

Keywords

  • anode material
  • graphene composite
  • lithium ion battery
  • nickel sulfide
  • spray pyrolysis

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry

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