Hierarchical zinc oxide/graphene oxide composites for energy storage devices

Highlights: • Graphene oxide (GO) decorated ZnO prepared by simple and aqueous precipitation method. • Structure of GO/ZnO composites was adjusted by the concentration and type of reagent. • The specific capacitance of the GO/ZnO composites was an increase of 83% than that of the graphene oxide. In this report, hierarchical graphene oxide/zinc oxide composites were fabricated by precipitation of zinc oxide on graphene oxide for supercapacitor electrode. An environmentally friendly and facile one-step precipitation method, was developed to synthesize the composites with graphene oxide and zinc oxide. The electrochemical performance of the graphene oxide/zinc oxide composites for energy storage was investigated. The maximum specific capacitance of 97 F/g at a current density of 0.5 A/g by galvanostatic charging-discharging was achieved in 1 M Na₂SO₄ electrolyte. The specific capacitance presented an increase of 83% with respect to the graphene oxide electrode. In addition, graphene oxide with zinc oxide electrode showed 90.8% retention of the specific capacitance for 5000 cycle tests. The results suggest that graphene oxide/zinc oxide composites offer a promising material for supercapacitor electrode.