NiCo2S4@Ni3S2 hybrid nanoarray on Ni foam for high-performance supercapacitors

Abstract

Integrated hybrid nanoarrays with hierarchical porous structures have attracted much attention as energy materials for their excellent synergistic effects. Herein, we provide a facile strategy for integrating a NiCo₂S₄@Ni₃S₂ hybrid nanoneedle array on nickel foam derived from metal–organic framework (MOF) precursors and a Ni/Co-precursor by sulfurization. When directly used as the free-standing electrode for a supercapacitor, the NiCo₂S₄@Ni₃S₂ electrode exhibited a high specific capacitance of 1536.8 F g⁻¹ at 1 A g⁻¹. Furthermore, the assembled NiCo₂S₄@Ni₃S₂//AC asymmetric supercapacitor (ASC) exhibited a high energy density of 35.26 W h kg⁻¹ at a power density of 724.93 W kg⁻¹. The capacitance retention of NiCo₂S₄@Ni₃S₂ was up to 97.4% after 10 000 cycles.