In situ growth of NiCo2S4@Ni3V2O8 on Ni foam as a binder-free electrode for asymmetric supercapacitors

Abstract

A hierarchical NiCo₂S₄@Ni₃V₂O₈ core/shell hybrid was in situ grown on nickel foam through a facile hydrothermal process combined with a simple co-precipitation method. Further characterization shows that the hybrid consists of highly conductive NiCo₂S₄ as the core and uniformly distributed Ni₃V₂O₈ nanoparticles as the shell. When used as the binder-free electrode, the hybrid material takes advantage of both components and exhibits excellent electrochemical activity, demonstrating a higher specific capacity of 512 C g⁻¹ at a current density of 1 A g⁻¹ and a better rate capability of 396 C g⁻¹ at 10 A g⁻¹. The enhanced pseudocapacitive performance of the NiCo₂S₄@Ni₃V₂O₈ hybrid is mainly attributed to its unique core/shell structure, which provides fast ion and electron transport. Finally, a NiCo₂S₄@Ni₃V₂O₈//activated carbon asymmetric supercapacitor is successfully assembled and it can deliver a maximum energy density of 42.7 W h kg⁻¹ at a power density of 200 W kg⁻¹, making it a promising candidate for superior electrodes for supercapacitor applications.