Supercapacitors with high capacitance based on reduced graphene oxide/carbon nanotubes/NiO composite electrodes

We present a facile method to fabricate well-crystalline reduced graphene oxide (RGO)/carbon nanotubes (CNTs)/NiO composites for supercapacitor electrodes. The RGO/CNT/NiO (GCN) composite takes dual advantages of CNTs and RGO. CNTs present the aggregation of RGO/NiO and improve the electron transport of GCN composites owing to their good conductivity. The restricting effect of RGO makes NiO nanoparticles have more active sites. Attributed to the uniform structure and improved electrical conductivity, GCN composites exhibit highly enhanced electrochemical performance compared with that of RGO/NiO and CNT/NiO composites. The specific capacitance of GCN composites is about 1180 F g−1 at 1 A g−1 together with a capacitance retention of 95% (1000 F g−1) over 2000 cycles at 4 A g−1. GCN composites have proven to be very promising as energy storage electrode materials.