Tiny Basic Nickel Carbonate Arrays/Reduced Graphene Oxide Composite for High-Efficiency Supercapacitor Application

3D structure composite made of tiny basic nickel carbonate arrays on the surface of reduced graphene oxide nanosheets (G-NiCH) are prepared by the hydrothermal method. The specific surface area of the G-NiCH composites is twice that of single basic nickel carbonate, which is due to the tiny basic nickel carbonate arrays structure wherein each individual nanoneedle is about 20 nm in length and 2 nm in width. The G-NiCH electrodes display high-efficiency electrochemical performance with good specific capacitance (1230 F g(-1)) and excellent stability (100% capacitance retention after 2000 cycles). This is attributed to the synergistic effect that reduced graphene oxide offer fast electron transmission path and basic nickel carbonate act as high effective active material.