Performance comparison of NiCo₂O₄ and NiCo₂S₄ 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.