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

Abstract

Cauliflower‐like Co 3 O 4 /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 Co 3 O 4 ). 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 Co 3 O 4 /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 Co 3 O 4 , which leads to a strong synergistic effect to remarkably boost the utilization ratio of Co 3 O 4 and graphene for high capacitance.