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

Aligned NiCo2S4 nanotubes on Ni foam were obtained by the complete sulfidation of NiCo-precursor which was synthetized by hydrothermal process. The NiCo2S4 nanotubes on Ni foam delivered a higher specific capacitance than NiCo2O4 nanowires on Ni foam. The NiCo2S4 nanotubes on Ni foam exhibited the high capacitance of 1936.2 F g−1 at 1 A g−1. The porous NiCo2S4 nanotubes on Ni foam provided a huge number of exposed active sites for electrochemical reaction. Moreover, the NiCo2S4 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 NiCo2S4 nanotubes on Ni foam.