Functionalized Graphene-Based Nanocomposites for Supercapacitor Application

A modern technological society demands the use and storage of energy on a large scale. In this regard, the development of high performance supercapacitors is the focus of current scientific research. Graphene, due to its excellent properties, has attracted attention for supercapacitor applications. In the present work, graphene is synthesized via hydrogen-induced exfoliation and is further functionalized to decorate with metal oxide (RuO2, TiO2, and Fe3O4) nanoparticles and polyaniline using the chemical route. Materials are characterized by electron microscopy, X-ray diffraction, Fourier transform infrared, and Raman spectroscopy techniques. Electrochemical performance of as-prepared graphene (HEG), functionalized graphene (f-HEG), RuO2-f-HEG, TiO2-f-HEG, Fe3O4-f-HEG, and PANI-f-HEG (PANI = polyaniline) nanocomposites is examined using cyclic voltammetry and galvanostatic charge-discharge techniques for supercapacitor applications. A maximum specific capacitance of 80, 125, 265, 60, 180, and 375 F/g for HEG, f-HEG, RuO2-f-HEG, TiO2-f-HEG, Fe3O4-f-HEG, and PANI-f-HEG nanocomposites, respectively, is obtained with 1 M H2SO4 as the electrolyte at the voltage sweep rate of 10 mV/s. The specific capacitance for each nanocomposites sustains up to 85% even at higher voltage sweep rate of 100 mV/s. A simple and cost-effective preparation technique of graphene and its nanocomposites with good capacitive behavior encourages its commercial use.