Fast supercapacitors based on graphene-bridged V2O3/VOx core-shell nanostructure electrodes with a power density of 1 MW kg-1

Xuan Pan, Guofeng Ren, Md Nadim Ferdous Hoque, Stephen Bayne, Kai Zhu, Zhaoyang Fan

Research output: Contribution to journalArticlepeer-review

88 Scopus citations

Abstract

Transition metal oxides (TMOs), with their very large pseudocapacitance effect, hold promise for next generation high-energy-density electrochemical supercapacitors (ECs). However, the typical high resistivity of TMOs restricts the reported ECs to work at a low charge-discharge (C-D) rate of 0.1-1 V s-1. Here, a novel vanadium oxides core/shell nanostructure-based electrode to overcome the resistivity challenge of TMOs for rapid pseudocapacitive EC design is reported. Quasi-metallic V2O3 nanocores are dispersed on graphene sheets for electrical connection of the whole structure, while a naturally formed amorphous VO2 and V2O5 (called as VOx here) thin shell around V2O3 nanocore acts as the active pseudocapacitive material. With such a graphene-bridged V2O3/VOx core-shell composite as electrode material, ECs with a C-D rate as high as 50 V s-1 is demonstrated. This high rate was attributed to the largely enhanced conductivity of this unique structure and a possibly facile redox mechanism. Such an EC can provide 1000 kW kg-1 power density at an energy density of 10 Wh kg-1. At the critical 45° phase angle, these ECs have a measured frequency of 114 Hz. All these indicate the graphene-bridged V2O3/VOx core-shell structure is promising for fast EC development. A graphene-bridged V2O3/VOx core-shell nanostructure based supercapacitor demonstrates an extremely high charge-discharge rate (50 V s-1) and a high-power density performance. In this structure, quasi-metallic V2O3 nanocores are dispersed on graphene sheets for electrical connection of the whole structure, while a naturally formed amorphous VO2 and V2O5 (or VOx) thin shell around the V2O3 nanocore acts as the active pseudocapacitive material.

Original languageEnglish
Article number1400398
JournalAdvanced Materials Interfaces
Volume1
Issue number9
DOIs
StatePublished - Dec 1 2014

Keywords

  • graphene
  • high-power density
  • hydrogen processing
  • supercapacitor
  • vanadium oxide

Fingerprint

Dive into the research topics of 'Fast supercapacitors based on graphene-bridged V<sub>2</sub>O<sub>3</sub>/VO<sub>x</sub> core-shell nanostructure electrodes with a power density of 1 MW kg<sup>-1</sup>'. Together they form a unique fingerprint.

Cite this