High-performance hybrid supercapacitor enabled by advantageous heterojunction boosted starfish-like ZnCo-S electrode

Abstract

Transition metal sulfides are regarded as attractive battery-type electrode materials for hybrid supercapacitors (HSCs) owing to their pronouncedly elevated theoretical capacity and good electrical conductivity. The rational design and manufacturing of multiphase materials are efficient strategies for improving electrode materials' electrochemical performance. Therefore, starfish-like ZnCo-S sulfide composite electrode materials were constructed as advanced hybrid supercapacitor electrode materials by co-precipitation and hydrothermal methods. The ZnCo-S features a higher specific surface area, multi-level pore structure, and heterogeneous interfacial effect, which can contribute abundant active sites and shorter charge transport paths for electrochemical reactions, resulting in distinguished electrochemical performance. The specific capacity of ZnCo-S sulfide composite electrode material is as high as 1171.6 C g−1 at 2 A g−1. The assembled solid-state hybrid supercapacitor has outstanding energy density (64 Wh kg−1) and power density (16 kW kg−1) with a capacity retention rate of 92.7% after 10,000 cycles.