In-situ synthesis of vanadium pentoxide nanofibre/exfoliated graphene nanohybrid and its supercapacitor applications

Abstract

A novel nanohybrid material composed of vanadium pentoxide nanofibres (VNFs) and exfoliated graphene were prepared by in-situ growth of VNFs onto graphene nanosheets, and explicated as electrode material for supercapacitor applications. The existence of non-covalent interactions between VNFs and graphene surfaces was confirmed by Raman and Fourier transform infrared (FTIR) spectroscopes. Morphological analysis of the nanohybrid revealed that the VNF layer uniformly grown on the graphene surfaces, producing high specific surface area and good electronic or ionic conducing path. High crystalline structure with small d-spacing of the VNFs on graphene was observed in X-ray diffraction (XRD) analysis. Compared to pristine VNF, the VNF/graphene nanohybrid exhibited higher specific capacitance of 218 F g−1 at current density of 1 A g−1, higher energy density of 22 Wh kg−1 and power density of 3594 W kg−1. Asymmetric supercapacitor devices were prepared using the Spectracarb 2225 activated carbon cloth and VNF/graphene nanohybrid as positive and negative electrode, respectively. The asymmetric device exhibited capacitance of 279 F g−1 at 1 A g−1, energy density of 37.2 Wh kg−1 and power density of 3743 W kg−1, which are comparable and or superior to reported asymmetric devices consisting of carbon material and metal oxide as electrode components.