Cauliflower-Like Co3O4/Three-Dimensional Graphene Composite for High Performance Supercapacitor Applications

Abstract

Cauliflower-like Co3O4/three-dimensional (3D) graphene nanocomposite material was synthesized by a facile two-step synthesis route (heat reduction of graphite oxide (GO) and hydrothermal synthesis of Co3O4). The phase composition, morphology, and structure of the as-obtained products were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). Electrochemical properties as supercapacitor electrode materials were systematically investigated by cyclic voltammetry (CV) and constant current charge-discharge tests. It was found that the Co3O4/3D graphene composite showed a maximum specific capacitance of 863 F g-1, which was obtained by means of CVs at a scan rate of 1 mV s-1 in 6 M KOH aqueous solution. Moreover, the composite exhibited improved cycling stability after 1,000 cycles. The good supercapacitor performance is ascribed to the combination of 3D graphene and cauliflower-like Co3O4, which leads to a strong synergistic effect to remarkably boost the utilization ratio of Co3O4 and graphene for high capacitance.