Co-construction of heterostructure and sulfur vacancies in bimetallic sulfides hollow nanopompons enhanced electrochemical performance

Abstract

Tailoring the performance of supercapacitors (SCs) by design is a critical challenge in high-performance energy storage. Herein, density functional theory (DFT) was utilized to analyze the potential of a sulfur-cobalt–nickel composite material as a supercapacitor. Specifically, heterogeneous NiCo₂S₄@ZnS hollow spheres with disulfide vacancies (V-NiCo₂S₄@V-ZnS) were produced by reducing the Ni/Co-LDH@ZIF-8 precursor. The electrochemical performance of the composites is significantly enhanced by the synergistic effect of the NiCo₂S₄@ZnS hetero-interface, hollow structure, and disulfide vacancy. The V-NiCo₂S₄@V-ZnS heterostructures demonstrate superior specific capacitance, excellent rate capability, and long cycle life (retaining 88.60% after 10000 cycles at 10 A/g), surpassing pure NiCo₂S₄ and ZnS materials. Notably, an asymmetric supercapacitor composed of these heterostructures achieves a maximum energy density of 47.9 Wh/kg at 4000 W/kg and maintains good cycle stability (90.24% after 10000 cycles), presenting promising prospects for future energy storage developments.