Interfacial coupling and redox engineering in CoS-NiSe2 heterostructures for high-performance asymmetric supercapacitors

The growth of the next-generation supercapacitors is challenged by inherent constraints on specific capacitance, rate capability, and structural durability. Despite the promising electrochemical properties of CoS, its structural instability and volume variation during repeated charge-discharge cycles limit its practical application. Here, a CoS-NiSe 2 heterostructure is engineered to enhance charge-transfer kinetics via interfacial coupling between CoS and NiSe 2 . In this research, the role of CoS-NiSe 2 nanocomposite in the electrode’s electrochemical properties has been investigated. The findings revealed that the CoS-NiSe 2 nanocomposite electrode exhibits a specific capacitance of 871 Fg⁻¹ at a current density of 1 Ag⁻¹, with low resistance in the three-electrode setup. Based on the three-electrode performance, the CoS-NiSe 2 ||AC asymmetric supercapacitor demonstrated impressive performance metrics, including a superior specific capacitance of 173 Fg − 1 , an energy density of 61.5 Whkg − 1 , and a maximum power density of 4010 Wkg − 1 . The ASC device also exhibited exceptional cycling stability, sustaining 91.4% of its capacity after 5,000 charge-discharge cycles at 8 Ag − 1 . The present synthesis strategy highlights an economically feasible and highly efficient route for developing high-performance asymmetric supercapacitors, paving the way for their potential deployment in future energy storage systems.