Synthesis of MXene-based Nanocomposites for Supercapacitor Application

Abstract

Two-dimensional multilayered MXene is a promising electrode material for supercapacitor application. Studies have revealed that using MXene as electrode material in supercapacitors yields a high specific capacitance and enhanced electrochemical performance. However, the twodimensional structure of MXene nanosheets are prone to self-restacking due to Van der Waals forces, which decreases the active sites for ion adsorption-desorption, thereby limiting its electrochemical properties. We devised a strategy to overcome this issue, by making a composite of MXene with activated carbon (AC) can not only prevent aggregation of MXene sheets, but the porous structure of AC can also provide abundant channels for rapid electrolyte ion transport. Biomass derived activated carbon was successfully synthesized by KOH activation method. It not only showed superior electrochemical properties but is also a cost-effective and sustainable alternative to other carbon materials. The synthesized MXene/AC composites demonstrated excellent electrochemical performance which is ascribed to the high porosity and surface area offered by activated carbon, and the synergistic effect of excellent conductivity of MXene and biomass derived activated carbon. XRD pattern confirmed the successful synthesis of MXene, AC and their composites. Raman revealed that degree of disorder increases, and degree of graphitization decreases with increase in AC content in MXene. BET analysis showed a similar trend, an increase in the surface area of the composites with an increased amount of AC. SEM showed the successful transformation of MXene from MAX phase, porous structure of AC and a 2D/3D conductive network of MXene/AC composites. Electrochemical analysis revealed MAC3 exhibited a high specific capacitance of 1080 F/g at 5 mV/s, outperforming both MXene and activated carbon. MAC3 also displayed a good cyclic stability of 81.1% and a Coulombic efficiency of 98.5% after 300 cycles. These results indicate that the synthesized MXene/AC composite can be used as an efficient electrode material for enhanced performance of supercapacitors.