Integrated design and construction of the NiMoS4@Co9S8/Ni3S2 hollow core–shell heterostructure for high-performance asymmetric supercapacitors

Abstract

Multi-component metal sulfide heterostructures possess a modulated electronic structure, abundant active sites and various morphology features, which are kinetically beneficial for fast electron/ion transport to enhance the energy storage performance. Herein a novel NiMoS₄@Co₉S₈/Ni₃S₂ core–shell heterostructure is designed and constructed, which consists of Co₉S₈/Ni₃S₂ heterogeneous hollow nanotubes as the core and NiMoS₄ nanospheres as the shell. The hierarchical NiMoS₄@Co₉S₈/Ni₃S₂ array has the merits of each component and exhibits excellent electrochemical performance due to the synergistic effect. When examined as the supercapacitor electrode, an area specific capacitance of 9.61 F cm⁻² was provided at a current density of 2 mA cm⁻². In addition, the assembled asymmetric supercapacitor device achieves superior properties regarding high energy density of 0.44 mW h cm⁻² at a power density of 2.30 mW cm⁻² and good durability with 82.67% capacitance retention over 5000 cycles. This work sheds light on the design and construction of multi-component heterostructure with well-defined hollow core–shell morphology, which is an effective strategy to fabricate electrode materials for high performance energy storage devices.