Graphene/NiO nanowires: controllable one-pot synthesis and enhanced pseudocapacitive behavior

In this study, we report a facile and simple approach to synthesize a composite of mesoporous NiO nanowires and graphene nanosheets for supercapacitor applications. A Ni precursor was prepared by a one-pot sol-gel method in a water/ethylene glycol mixture containing a graphene oxide. Heat treatment in air was carried out to thermally reduce the graphene oxide to graphene and to convert the Ni precursor to NiO. NiO nanowires possess a rough surface, have a diameter of around 60 nm and are homogeneously deposited on the graphene sheets. The NiO/graphene nanocomposite demonstrates superior pseudocapacitive properties (high specific capacitance, good cyclic performance, and excellent discharge rate capability) as compared to its counterparts. We postulated that this phenomenon arose from the synergistic effect of the addition of graphene as elastic conductive channels, which resulted in better charge transport and more favorable ionic diffusion.