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

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/cm(2) while of FeVO4 was 97.54F/g @ 0.5 mA/cm(2). 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.