Performance comparison of NiCo 2 O 4 and NiCo 2 S 4 formed on Ni foam for supercapacitor

Abstract

Abstract Aligned NiCo 2 S 4 nanotubes on Ni foam were obtained by the complete sulfidation of NiCo-precursor which was synthetized by hydrothermal process. The NiCo 2 S 4 nanotubes on Ni foam delivered a higher specific capacitance than NiCo 2 O 4 nanowires on Ni foam. The NiCo 2 S 4 nanotubes on Ni foam exhibited the high capacitance of 1936.2 F g −1 at 1 A g −1 . The porous NiCo 2 S 4 nanotubes on Ni foam provided a huge number of exposed active sites for electrochemical reaction. Moreover, the NiCo 2 S 4 nanotubes on Ni foam with large specific surface area facilitated the diffusion and penetration of electrolyte and improved electrochemical reaction. Therefore, after 5000 continuous charge–discharge cycles, only about 7.9% degradation in specific capacitance was observed for NiCo 2 S 4 nanotubes on Ni foam.