Comparative electrochemical analysis of rGO-FeVO4 nanocomposite and FeVO4 for supercapacitor application

Abstract

Abstract Novel FeVO4 and rGO-FeVO4 nanocomposite are synthesized by co-precipitation method and sonochemical method post co-precipitation and modified Hummer's method. The structural and morphological studies were carried out by X-Ray Diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopic (SEM) measurements. XRD studies confirm that FeVO4 is in single phase having triclinic crystal structure with space group P-1(2). Raman spectra of FeVO4, GO, and rGO-FeVO4 nanocomposite show characteristic peaks of FeVO4, GO and both FeVO4 & GO signatures together, respectively. Electrochemical characterization of the samples is done by using Cyclic Voltammetric (CV), Galvanometric Charging Discharging (GCD) and Electrochemical Impedance Spectroscopic (EIS) analysis methods. Cyclic voltammogram of rGO-FeVO4 nanocomposite manifests the pseudo-capacitor nature. The specific capacitance of rGO-FeVO4 nanocomposite is found to be 189.10 F/g @ 0.5 mA/cm2 while of FeVO4 was 97.54F/g @ 0.5 mA/cm2. A two-fold increase in specific capacitance is found for rGO–FeVO4 composite as compared to FeVO4. Extensive DFT simulations were carried out to study the structural and electronic properties of FeVO4 and rGO-FeVO4 hybrid structure and to bring theoretical insight for the enhanced specific capacitance in the hybrid structure.