Hollow Metal-Organic Framework-Derived Layered NiS2/MXene Composites for High-Performance Supercapacitors

Abstract

MXene, characterized by its unique layered structure, shows great promise as an electrode material for energy storage devices. MXene-based electrode materials, with their excellent metallic conductivity, high packing density, and large specific surface area, efficiently store high-rate Faradaic pseudocapacitive energy. This study successfully synthesizes a layered NiS₂/MXene composite using a self-assembly method. The structural design significantly increases the composite material's specific surface area and active sites while effectively suppressing the restacking of MXene nanosheets. Furthermore, the MXene layer wrapped around NiS₂ not only improves electrical conductivity but also stabilizes the hollow structure to prevent collapse. Test results reveal that the NiS₂/MXene composite demonstrates a specific capacitance of 1016 F g⁻¹ at a current density of 1 A g⁻¹. The asymmetric supercapacitor achieves an energy density of 46.6 Wh kg⁻¹ at a power density of 698.7 W kg⁻¹, with excellent cycling stability. This study proposes a novel design strategy for asymmetric supercapacitor electrodes incorporating metal-organic frameworks and MXene composites.