EFFECT OF ELECTROLYTE ON THE CHARGE STORAGE CHARACTERISTICS OF Mo2CTx MXene ELECTRODES FOR SUPERCAPACITORS

In this work, Mo2CTx MXene was successfully synthesized via selective etching of the Ga layer from the Mo2Ga2C precursor using concentrated HF solution. Its electrochemical performance was systematically investigated in 1 M H2SO4, 1 M Na2SO4, and 1 M CH3COONa aqueous electrolytes. The results show that the charge storage behavior of Mo2CTx is strongly dependent on the electrolyte, with the highest specific capacitance achieved in 1 M H2SO4, reaching 70.47 F g-1 at 10 mV s-1 from CV and 103.50 F g-1 at 1 A g-1 from GCD, compared with 48.85 and 55.00 F g-1 in CH3COONa and 46.29 and 49.78 F g-1 in Na2SO4, respectively. The superior performance in H2SO4 is attributed to the high mobility of H⁺and more favorable ion transport kinetics, as supported by the lower Warburg coefficient. In addition, Mo2CTx exhibits good cycling stability, retaining 94.89%, 89.64%, and 73.57% of its initial capacitance after 5,000 cycles in H2SO4, Na2SO4, and CH3COONa, respectively. These findings demonstrate the critical role of electrolyte chemistry in governing charge storage, ion transport, and cycling stability of Mo2CTx MXene and provide insights for optimizing MXene-based supercapacitor electrodes.