Synthesis of honeycomb-like NiS2/NiO nano-multiple materials for high performance supercapacitors

•3D honeycomb-like NiS2/NiO were prepared via a green hydrothermal process.•The NiS2 reduces the electrochemical impedance of NiO.•The NiS2/NiO electrode exhibits exceptional electrochemical performance.

Three dimensional (3D) honeycomb-like NiS2/NiO nano-multiple materials were successfully prepared by fabricating cribrate NiS2 on the surface of NiO nanosheets through simple hydrothermal process on nickel foam. The morphology and phase structure of the NiS2/NiO are characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer, transmission electron microscope, X-ray diffractometer and the electrochemical properties are tested by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The NiS2/NiO electrode owns lower electrochemical impedance compared with bare NiO substrate and exhibits exceptional capacitance performance with a high specific capacitance of 2251 F g−1 delivered at current density of 1 A g−1, while 1192 F g−1 retained at 20 A g−1. What's more, after 2000 cycles, the specific capacitance remains 1275 F g−1 (at 5 A g−1) with a capacitance retention of 78%. Therefore, the NiS2/NiO electrode shows remarkable electrochemical performance and has a promising future for electrochemical supercapacitors.