Green synthesis and electrochemical performances of ZnO/graphene nanocomposites

ZnO/graphene nanocomposites were prepared for supercapacitance materials through a simple two-step process involving chemical oxidation of flake graphite powders and solvothermal synthesis of ZnO/graphene nanocomposites in ethanol. The structure, Brunauer-Emmett-Teller surface area, composition, and morphology of the as-prepared materials were characterized by X-ray diffraction, N 2 adsorption/desorption analysis, Fourier transform infrared spectroscopy, and transmission electron microscopy. Results showed that the ZnO nanorods had wurtzite structure and were successfully loaded on the graphene sheets. The electrochemical properties of ZnO/graphene nanocomposites formed by different masses of graphite oxide to zinc acetylacetonate were evaluated by means of cyclic voltammetry and galvanostatic charge-discharge studies. The nanocomposite prepared with graphite oxide (60 mg) and zinc acetylacetonate (15 mg) showed a high specific capacitance of 188 Fg −1 at a current density of 0.1 Ag −1 in the 6 M KOH solution and better long-term stability along with 98.25% of its initial capacitance after 1500 cycles at 1.2 Ag −1 .