In situ grown VO2/V2C MXene and its supercapacitor applications

MXene, a newly emerging two-dimensional material, has a wide range of potential applications, particularly in supercapacitors. However, MXene electrodes have limited specific capacity mainly because of their energy storage characteristics that rely on electrostatic adsorption on the surface. Supercapacitor applications require nanostructured electrode materials with enhanced electrochemical performance in terms of specific capacity and nanostructure stability. Motivated by this requirement, rational design and construction of advanced hybrid electrodes would contribute to enormous development of supercapacitors. In this study, we developed a new strategy to fabricate oxidized VO2/V2C MXene anodes from vanadium carbide (V2C) MXene using a hydrothermal method. Charge transformation during the adsorption/desorption process in supercapacitor applications was enhanced by altering the nanostructure of VO2/V2C MXene and coupling V2C MXene with VO2. The results indicate that the VO2/V2CTx MXene//V2C MXene asymmetric supercapacitor (ASC) device delivered an energy density of 10.56 Wh L−1 at 127.8 W L−1 power density and maintained a capacity retention rate of 74.2 % after 5000 cycles. This shows that using VO2/V2CTx MXene as a positive electrode and V2CTx MXene as a negative electrode in the ASC is a promising strategy for enhancing both energy and power densities of supercapacitors.