Abstract: Supercapacitors are demonstrated significant application potential in the energy storage field due to their high power density, rapid charge-discharge capability, and long cycle life. However, their relatively low energy density restricts further development. In this study, porous flowerball-like NiCo₂O₄/Co₃S₄-M heterostructured electrode materials were constructed via hydrothermal method, template-assisted growth, and sulfuration treatments, and their electrochemical performance was systematically investigated. In three-electrode system, NiCo₂O₄/Co₃S₄-M exhibits a specific capacitance of 2362 F·g^-1 at 1 A·g^-1. The porous flowerball structure affords abundant active sites, and the heterointerface facilitates electron/ion transport, synergistically boosting both conductivity and stability. Furthermore, an asymmetric supercapacitor (NiCo₂O₄/Co₃S₄-M//PC) was assembled using NiCo₂O₄/Co₃S₄-M flowerball as the cathode and porous carbon (PC) as the anode, achieving a high energy density of 98.4 Wh·kg^-1 at a power density of 375 W·kg^-1, which maintained 45.42 Wh·kg^-1 with the power density even increased to 7500 W·kg^-1, along with outstanding cycling stability. After 10000 cycles at a current density of 5 A·g^-1, the capacitance retention rate reached 99.7% with a Coulombic efficiency of 97.56%. This study indicates that the strategy of heterostructure design and microstructure modulation can effectively achieve high specific capacity and superior cycling stability, providing new research insights for the development of high-performance supercapacitor electrode materials.

Key words: porous flowerball, heterostructure, high specific capacitance, cycling stability, supercapacitor