One-Step Synthesis of Self-Supported Ni(3)S(2)/NiS Composite Film on Ni Foam by Electrodeposition for High-Performance Supercapacitors

Herein, a facile one-step electrodeposition route was presented for preparing Ni(3)S(2)/NiS composite film on Ni foam substrate (denoted as NiS(x)/NF). The NiS(x) granular film is composed of mangy interconnected ultra-thin NiS(x) nanoflakes with porous structures. When applied as electrodes for supercapacitors, the ultra-thin nanoflakes can provide more active sites for redox reaction, and the interconnected porous structure has an advantage for electrolyte ions to penetrate into the inner space of active materials quickly. As expected, the obtained NiS(x)/NF sample exhibited high gravimetric capacitance of 1649.8 F·g(−1) and areal capacitance of 2.63 F·cm(−2). Furthermore, a gravimetric capacitance of 1120.1 F·g(−1) can be maintained at a high current density of 20 mA·cm(−2), suggesting a good rate capability. The influence of the different molar ratios of electrodeposition electrolyte (NiNO(3) and thiourea) on the morphology and electrochemical properties of NiS(x)/NF sample was investigated to provide an optimum route for one-step electrodeposition of Ni(3)S(2)/NiS composite film. The outstanding performance indicated the Ni(3)S(2)/NiS composite film on Ni foam has great potential as an electrode material for supercapacitors.