Heteroatom doped graphene based hybrid electrode materials for supercapacitor applications

Abstract

A series of vanadium pentoxide (V2O5/G) nanocomposites with graphene and doped graphene was synthesized by a facile solvothermal route and the supercapacitor performance of the obtained materials were further examined. The various heteroatom doped graphene composites viz. B doped (V2O5/BG), N doped (V2O5/NG) and BN codoped graphene (V2O5/BNG) was analyzed systematically to understand the effect of the dopants and their electrochemical properties. The structural and morphology of the obtained nanocomposites were investigated by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Thermogravimetric Analysis (TGA), Transmission Electron Microscope (TEM) and Brunauer, Emmett and Teller (BET). The results showed that the prepared V2O5 nanoparticles are deposited uniformly on graphene sheets. The electrochemical behavior of the nanocomposites were further analyzed to understand its supercapacitance properties in KOH electrolyte. A maximum specific capacitance of 1032.6 F/g was observed for V2O5/NG at 1 mVs-1 scan rate. Galvanostatic charge/discharge curves showed an excellent cyclic stability with higher charge/discharge duration with an energy density of 185.86 Wh/Kg and a power density of 37.20 W/Kg respectively for V2O5/NG nanocomposite. The graphene moieties provide fast and smooth electron transfer between V2O5 materials, thus leading to higher electrode performance compared with V2O5. The doping of heteroatom on graphene has been proven to be an effective way to tailor the properties of graphene and render its potential use for supercapacitor electrodes.