CuO nanorods grown vertically on graphene nanosheets as a battery-type material for high-performance supercapacitor electrodes

This work reports the preparation and characterization of the CuO nanorods grown vertically on graphene nanosheets, denoted as CuO/rGO@NF. Graphene is deposited by electrostatic attraction showing the morphology of folded nanosheets, which improves the electrical conductivity of the electrode, while CuO is modified by filtered cathodic vacuum arc technology and subsequent electrochemical oxidation presenting the morphology of nanorods, which increases the contact area of active sites and shortens the ion and electronic diffusion path. The results show that the CuO/rGO@NF electrode deliver an ultrahigh specific capacity (2.51 C cm(−2) at 2 mA cm(−2)), remarkable rate performance (64.6%) and improved conductivity. A symmetrical supercapacitor is assembled by two identical electrodes, presenting the maximum energy density of 38.35 W h kg(−1) at a power density of 187.5 W kg(−1). Therefore, the CuO/rGO@NF electrode can be used as a prospective electrode for energy storage devices. In addition, the whole electrode preparation process is short in time, safe and environmentally friendly, which provides a new idea for the preparation of other electrode materials.