Highly Oriented β-Bi2O3-decorated Reduced Graphene Oxide Composites for Supercapacitor Electrodes

Highly (201)-oriented beta-Bi2O3-decorated reduced graphene oxide (rGO) composites were prepared via a novel route using GO and bismuth nitrate as the raw materials in various mass ratios. First, GO solutions were obtained using the improved Hummer's method, and then the highly (201)-oriented beta-Bi2O3-decorated rGO composites were prepared by novel treatments after a hydrothermal treatment. The galvanostatic charge-discharge measurement results revealed that the composite with a GO: bismuth nitrate mass ratio of 1:1.2 exhibited the maximum specific capacitance of 196 F g(-1) at 1 A g(-1) in a 1 M KOH electrolyte. The as-obtained electrode maintained a minimum capacitance of 99.6% with excellent reversibility even after 3000 charge-discharge cycles. The electrochemical impedance spectroscopy results revealed that the as-obtained highly (201)-oriented beta-Bi2O3-decorated rGO composites showed lower impedance and better capacitance performance than rGO. Hence, the findings of this study demonstrated that highly (201)-oriented Bi2O3-decorated rGO composites can be used as supercapacitor electrodes.