β-Cyclodextrin-Stabilized CuO/MXene Nanocomposite as an Electrode Material for High-Performance Supercapacitors

Supercapacitors are the best energy storage systems due to their high power density, quick charge/discharge rate, and long-term reliability. In this study, β-cyclodextrin-stabilized CuO nanoparticles (CuO@βCD NPs) were synthesized through a simple reduction method and anchored on the surface of MXene nanosheets in three different proportions (1:1, 4:1, and 1:4) to obtain CuO@βCD/MXene nanocomposites through the wet-impregnation method. The formation of CuO@βCD NPs and their physicochemical characteristics were verified by XRD, XPS, FE-SEM, and HR-TEM analysis. The actual focus is on the evaluation of the electrochemical performances of CuO@βCD, MXene, and CuO@βCD/MXene nanocomposites for supercapacitor applications. The cyclic voltammetry and galvanostatic charge-discharge analysis revealed the pseudocapacitance and an improved specific capacitance of 1693.43 F g^-1 at 0.90 A g^-1 for the CuO@βCD/MXene (1:1) nanocomposite. The electrochemical impedance analysis displays superior electrical conductivity with a low charge transfer resistance value on incorporating CuO@βCD between the MXene layers. Furthermore, the CuO@βCD/MXene (1:1) nanocomposite exhibited improved long-term cycling stability by retaining 86% of its initial specific capacitance even after the 10,000th cycle at the current density of 4.54 A g^-1. Based on the electrochemical performance, the CuO@βCD/MXene (1:1) nanocomposite proves its suitability as an electrode material for supercapacitor application with long-term cycling stability and rate capability.