In Situ Construction of ZnO/NiS Composite on Ni Foam by Combing Potentiostatic Deposition with Cyclic Voltammetric Electrodeposition.

The ZnO/NiS composite has been designed and in situ synthesized on Ni foam substrate by two steps of electrodeposition. ZnO was achieved on Ni foam by a traditional potentiostatic deposition, followed by cyclic voltammetric (CV) electrodeposition, to generate NiS, where the introduction of ZnO provides abundant active sites for the subsequent NiS electrodeposition. The amount of deposit during CV electrodeposition can be adjusted by setting the number of sweep segment and scan rate, and the electrochemical characteristics of the products can be readily optimized. The synergistic effect between the ZnO as backbones and the deposited NiS as the shell enhances the electrochemical properties of the sample significantly, including a highly specific capacitance of 2.19 F cm at 2 mA cm, good coulombic efficiency of 98%, and long-term cyclic stability at 82.35% (4000 cycles).