High pseudocapacitance from ultrathin V2O5 films electrodeposited on self-standing carbon-nanofiber paper

Arunabha Ghosh, Eun Ju Ra, Meihua Jin, Hae Kyung Jeong, Tae Hyung Kim, Chandan Biswas, Young Hee Lee

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204 Scopus citations

Abstract

An ultrathin V2O5 layer was electrodeposited by cyclic voltammetry on a self-standing carbon-nanofiber paper, which was obtained by stabilization and heat-treatment of an electrospun polyacrylonitrile (PAN)-based nanofiber paper. A very-high capacitance of 1308 F g-1 was obtained in a 2 M KCl electrolyte when the contribution from the 3 nm thick vanadium oxide was considered alone, contributing to over 90% of the total capacitance (214 F g-1) despite the low weight percentage of the V2O5 (15 wt%). The high capacitance of the V 2O5 is attributed to the large external surface area of the carbon nanofibers and the maximum number of active sites for the redox reaction of the ultrathin V2O5 layer. This ultrathin layer is almost completely accessible to the electrolyte and thus results in maximum utilization of the oxide (i.e., minimization of dead volume). This hypothesis was experimentally evaluated by testing V2O5 layers of different thicknesses. An ultrathin film of V2O5 is electrodeposited on the surface of carbon nanofibers to obtain a high surface area with an improved electrode conductivity. This provides a high pseudocapacitance of 1308 F g-1 with respect to the effective contribution from the deposited oxide layer. The schematic shows the distribution of V2O5 throughout the nanofiber. The graph shows the dependence of the specific capacitance on the deposited amount of V2O5.

Original languageEnglish
Pages (from-to)2541-2547
Number of pages7
JournalAdvanced Functional Materials
Volume21
Issue number13
DOIs
StatePublished - 8 Jul 2011
Externally publishedYes

Keywords

  • carbon nanofibers
  • electrodeposition
  • high surface area materials
  • pseudocapacitance
  • ultrathin films of VO

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