Reduced Graphene Oxide-Cr2O3 Nanocomposite as Electrode Material in Supercapacitors

In recent years, electrochemical supercapacitors have received considerable attention from many researchers. Metal oxides such as chromium oxide with high redox activity, high specific capacity, and excellent reversibility are suitable alternatives to ruthenium oxide in supercapacitor applications. In this study, first, graphene oxide (GO) was synthesized by the modified Hummers method. The synthesized GO was reduced using hydrazine hydrate (HH.rGO) and thermal reduction (Th.rGO). Also, chromium oxide (Cr2O3) was synthesized using a simple method. The synthesized compounds were characterized using the scanning electron microscope, infrared spectroscopy, and X-ray diffraction methods. Then Cr2O3 and reduced GO were mixed in N-methyl pyrrolidone at a ratio of 20:80. Electrochemical properties of HH.rGO/Cr2O3 and Th.rGO/Cr2O3 nanocomposites were evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, and chronopotentiometry methods. The supercapacitor studies show that the nanocomposites have excellent reversible supercapacitor behavior and suitable electrochemical performance. The specific capacity of HH.rGO/Cr2O3 and Th.rGO/Cr2O3 electrodes were 101 F/g and 151 F/g, respectively at the scan rate of 2 mV/s. These results indicate that the composition of Cr2O3 with GO increases the specific capacity of supercapacitor due to the synergistic effect of GO and metal oxide.