High-performance NiCo2O4@Ni3S2 core/shell mesoporous nanothorn arrays on Ni foam for supercapacitors

Hierarchical NiCo2O4@Ni3S2 core/shell mesoporous nanothorn (NT) arrays were successfully designed and synthesized on the surface of Ni foam via a two-step process which includes hydrothermal synthesis and electrodeposition. The obtained core/shell nanostructures consist of NiCo2O4 mesoporous NTs as the core and interconnected Ni3S2 ultrathin nanosheets as the shell, which exhibit remarkable electrochemical performance for supercapacitors because of the heterogeneity synergies of the two components. Compared with the single component of either NiCo2O4 mesoporous NTs or Ni3S2 ultrathin nanosheets, the hierarchical NiCo2O4@Ni3S2 core/shell mesoporous NT arrays demonstrate a higher specific capacitance of 1716 F g(-1) at a current density of 1 A g(-1) and a better rate capability of 1104 F g (1) at 20 A g (1) while maintaining 83.7% capacity after 2000 cycles at a current density of 4 A g (1). Such superior electrochemical performance may originate from the unique hierarchical core/shell nanostructures that would possess faster ion and electron transfer, enhanced reactivity and modified structural integrity.