Potentiostatic deposition of CoNi2S4 nanosheet arrays on nickel foam: effect of depostion time on the morphology and pseudocapacitive performance

The bimetallic sulfide of CoNi2S4 nanosheet arrays have been successfully prepared via a facile one-step potentiostatic deposition on nickel foam using Co(NO3)2, NiCl2, and thiourea as the raw materials. The effect of deposition time on the morphology, structure, and electrochemical performance of the products is carefully investigated. The results show that when the potentiostatic deposition time is set as 10 min, the most uniform nanosheet arrays with the optimal supercapacitive performance are achieved on the nickel foam. The specific capacitance of material obtained under this condition is determined to be 1932 F g−1 at 2 A g−1 and 1640 F g−1 at 20 A g−1, respectively. The material retains 89.2 % of its original specific capacitance after 1000 charge–discharge cycles at a current density of 10 A g−1, demonstrating that the CoNi2S4 nanosheet arrays have an outstanding long-term cycling stability. These impressive performances can be ascribed to the unique architecture and properties of the deposited product, such as high interfacial contact area, rich redox activity, large pore size, and excellent conductivity. This work provides more supporting data to obtain high-performance supercapacitive bimetallic sulfide material by electrodeposition method.