Potentiostatic deposition of nickel cobalt sulfide nanosheet arrays as binder-free electrode for high-performance pseudocapacitor

To promote the development of supercapacitors, it is urgent to develop new class of electrode materials with low cost, high energy density and high power density. Ternary metal sulfides are one kind of promising electrode materials for high-performance energy storage devices. Here, a facile one-step potentiostatic deposition method is utilized to produce a binder-free, nanostructured NiCo2S4 electrode on FTO substrates. By controlling the Ni/Co mole ratio of the electrodepositing solution, the nanosheet-like NiCo2S4 free-standing electrode fabricated in the optimized condition exhibits a high specific capacitance of 1080 F g(-1) at a current density of 1 A g(-1). After 2000 cycles at 5 A g(-1), there is no loss of specific capacitance, which is ascribed to the unique structure of the nanosheet arrays. These results reveal that this method can be used as a facile route to synthesize free-standing NiCo2S4 nanosheets-based electrode material of supercapacitors.