Two-dimensional NiCo2O4 nanosheet-coated three-dimensional graphene networks for high-rate, long-cycle-life supercapacitors

Abstract

We report the synthesis of two-dimensional (2D) NiCo₂O₄ nanosheet-coated three-dimensional graphene network (3DGN), which is then used as an electrode for high-rate, long-cycle-life supercapacitors. Using the 3DGN and nanoporous nanosheets, an ultrahigh specific capacitance (2173 F g⁻¹ at 6 A g⁻¹), excellent rate capability (954 F g⁻¹ at 200 A g⁻¹) and superior long-term cycling performance (94% capacitance retention after 14 000 cycles at 100 A g⁻¹) are achieved.