Hybrid nanomaterial of α-Co(OH)2 nanosheets and few-layer graphene as an enhanced electrode material for supercapacitors

J. P. Cheng*, L. Liu, K. Y. Ma, X. Wang, Q. Q. Li, J. S. Wu, F. Liu

*Corresponding author for this work

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Supercapacitor with metal hydroxide nanosheets as electrode can have high capacitance. However, the cycling stability and high rate capacity is low due to the low electrical conductivity. Here, the exfoliated α-Co(OH)2 nanosheets with high capacitance has been assembled on few-layer graphene with high electric conductivity by a facile yet effective and scalable solution method. Exfoliated hydrotalcite-like α-Co(OH)2 nanosheets and few-layer graphene suspensions were prepared by a simple ultrasonication in formamide and N-methyl-2-pyrrolidone, respectively. Subsequently, a hybrid was made by self-assembly of α-Co(OH)2 and few-layer graphene when the two dispersions were mixed at room temperature. The hybrid material provided a high specific capacitance of 567.1 F/g at 1 A/g, while a better rate capability and better stability were achieved compared to that mad of pristine and single exfoliated α-Co(OH)2. When the hybrid nanocomposite was used as a positive electrode and activated carbon was applied as negative electrode to assembly an asymmetric capacitor, an energy density of 21.2 Wh/kg at a power density of 0.41 kW/kg within a potential of 1.65 V was delivered. The high electrochemical performance and facile solution-based synthesis method suggested that the hybrid of exfoliated α-Co(OH)2/few-layer graphene could be a potential electrode material for electrochemical capacitor.

Original languageEnglish (US)
Pages (from-to)344-350
Number of pages7
JournalJournal of Colloid And Interface Science
Volume486
DOIs
StatePublished - Jan 15 2017

Keywords

  • Cobalt hydroxide
  • Delamination
  • Electrochemical capacitor
  • Few-layer graphene

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry

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