Enhanced electrochemical performance of vanadium carbide MXene composites for supercapacitors

Abstract

Two-dimensional (2D) surface-terminated layered transition metal carbide MXenes with high electrochemical performance paved the way for robust energy storage supercapacitor devices. However, because of the 2D nature of the MXene flakes, self-restacking of 2D MXene flakes limits the use of all the flake functionalized surfaces in MXene electrodes. Here, we report the synthesis of V2CTx MXene and multiwall carbon nanotube (MWCNT)/V2CTx composites as a promising electrode material for hybrid energy storage devices. Our hybrid electrodes exhibited enhanced electrochemical performance and a gravimetric capacitance of 1842 F g−1 at a scan rate of 2 mV s−1, with a specific charge capacity of 62.5 A h/g. Moreover, the electrodes presented an excellent rate performance, durability, and retention capacity of 94% lasted up to 10 000 cycles. Density functional theory calculations provided electronic and structural properties of the considered MWCNT@V2CTx. Therefore, the introduction of MWCNTs enhanced the conductivity and reaction kinetics of the MXenes and facilitates the charge storage mechanism useful for next-generation smart energy storage devices.