A cabbage leaf like nanostructure of a NiS@ZnS composite on Ni foam with excellent electrochemical performance for supercapacitors.

In the present study, a NiS@ZnS composite nanostructure was synthesized on a nickel foam substrate by a facile chemical bath deposition (CBD) method. The prepared composites were analyzed by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and field emission scanning electron microscopy. The electrochemical performance of the supercapacitor (SC) electrodes was examined by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The NiS@ZnS composite exhibited a cabbage leaf like nanostructure and showed outstanding electrochemical performance in SCs with a specific capacitance of 1533.0 F g-1 at a current density of 7.5 A g-1, good cycling stability with 97.9% retention over 3000 cycles, greater energy density, and excellent rate capability compared to the bare NiS (1279.83 F g-1) and ZnS (616.66 F g-1)-based electrodes in SCs. The facile, novel synthesis method, outstanding performance, well defined surface morphology, synergetic effect and low cost make the NiS@ZnS composite an ideal electrode material for electrochemical energy storage devices.