Thermally stable Ag-decorated V2CTx MXene for enhanced pseudocapacitive energy storage

In this study, we reported the synthesis of V₂CT_x MXene from precursor MAX V₂AlC with silver nanoparticles (Ag NPs) incorporated into the layered structure of MXene by electrostatic self-assembly method. The as-prepared electrode Ag NPs incorporated V₂CT_x MXene showed an outstanding specific capacitance of 618.7F/g at 1 A/g for charge storage performance in an alkaline electrolyte (1 M KOH). Owing to the conductive channel provided by the silver nanoparticles in the MXene sheet the hybrid exhibited 89 % of ion diffusion-controlled process. Electrochemical impedance spectroscopy was further conducted to investigate the kinetics and surface properties of the prepared electrodes which in the case of V₂CT_x MXene/Ag-NPs hybrid shows the lower charge transfer resistance (R_ct, of 7.900 Ω) and solution resistance (R_s, of 789.0e-3 Ω) indicating the porosity of the material having sufficient surface area. Furthermore, the AC/Ag NPs/V₂CT_x asymmetric device tested for practical application demonstrated 98 % cyclic stability and 99 % coulombic efficiency for 5000 cycles at a current density of 5 A/g and a specific capacitance of 63.6F/g at 1 A/g. The V₂CT_x MXene/Ag-NPs electrode exhibited various interesting factors for energy storage in aqueous electrolytes.