Self-Assembly of Nickel Cobalt Sulfide/MXene Microspheres for Supercapacitors With Excellent Electrochemical Performance

Abstract

MXene, a novel 2-D material known for its exceptional conductivity and high hydrophilicity, holds significant promise in advancing supercapacitor technology. However, its layered structure tends to self-stack, hindering ion transport and limiting its specific capacitance. In this paper, nickel cobalt sulfide (NCS)/MXene self-assembled microspheres were prepared by a simple hydrothermal method. The introduction of NCS effectively mitigates MXene from self-stacking, while providing abundant electrochemical active sites that enhance its performance. NCS/MXene demonstrates an exceptional specific capacitance of 2544.1 F g⁻¹ at 1 A g⁻¹, surpassing the specific capacitance of both pure MXene and NCS. Moreover, it exhibits outstanding stability, maintaining 96% of its capacity after 5000 cycles. When assembled into asymmetric supercapacitors, the device achieves a high energy density of 43.2 Wh kg⁻¹ at a power density of 768.1 W kg⁻¹. This work provides a simple and reliable method for the development of sulfide/MXene composite electrode materials for supercapacitors.