Ni-foam modified binder-free Ni3S2 electrode for improved cyclic performance in asymmetric supercapacitors

Abstract

The rising interest in binder-free electrode supercapacitors can be attributed to their outstanding electrochemical performance and seamless compatibility with a diverse range of electronic devices. This study show cases the successful development of a binder-free electrode, facilitating the direct growth of Ni3S2 nanostructures on Ni foam substrate, resulting in the development of high-performance supercapacitors. The formation of 0.5@Ni3S2, 1@Ni3S2, 2@Ni3S2, and 3@Ni3S2 with a heazle-woodite-phase structure was confirmed through X-ray diffraction, grown by the direct sulfurization of the Nickel foam surface into Ni3S2 using a straightforward one-step hydrothermal process with varying quantities of sulfur source. Field emission scanning electron microscopy (FESEM) was employed to visualize the continuous porous micro-networks on Ni foam surface. In a three-electrode system, the supercapacitor exhibited a capacitance of 418.46 F/g at 2 A/g. Furthermore, the Ni3S2//AC asymmetric supercapacitor device demonstrated remarkable performance with a specific capacitance of 192.24 F/g, an energy density of 65.42 Wh/kg, and a power density of 2966.14 W/kg @ 1 A/g. Impressively, even after undergoing 8000 charge-discharge cycles, these devices retained 51% of their initial capacitance.