Preparation of Zn, Mo co-doped NiCo₂S₄ electrode material and its electrochemical performance for supercapacitors

NiCo₂S₄ nanoarrays have shown broad application prospects in the field of supercapacitors due to their excellent electrical conductivity and high theoretical specific capacity. However, the actual specific capacity is usually much lower than the theoretical value, which is mainly limited by the insufficient utilization of active sites and the slow kinetics of ion/electron transport. In order to solve this problem, zinc/molybdenum (Zn, Mo) co-doped NiCo₂S₄ nanoarrays were successfully prepared by two-step hydrothermal method using carbon cloth (CC) as the substrate. At a current density of 1 mA·cm⁻², the area specific capacitance of the electrode reaches 3198.73 mF·cm⁻², which is much higher than that of undoped modified sample. When the current density is increased to 20 mA·cm⁻², the electrode material still has an initial capacitance of 63.21%. Furthermore, an asymmetric supercapacitor (CC@Zn₅Mo₅-NiCo₂S₄//AC) was assembled by using Zn₅Mo₅-NiCo₂S₄ and activated carbon (AC). The specific capacitance of the device is 65.8 F·g⁻¹ at a current density of 0.35 A·g⁻¹. After 5000 cycles of charge and discharge tests at a current density of 1.75 A·g⁻¹, the device still maintains an initial capacitance of 60.37%, and the coulombic efficiency is stable at 96.6%. This study provides a reference for the development of high-performance supercapacitor electrode materials.