Pseudocapacitive Behavior of Blade-Coated Mo_1.33CT_x i-MXene Electrodes in Aqueous Electrolytes

Two-dimensional molybdenum carbide (Mo_1.33CT_x MXene) with ordered vacancies is one of the most promising materials for electrochemical energy storage. However, the high defectivity and tendency to aggregate of nanosheets hinders the large-scale fabrication of highly efficient Mo_1.33CT_x -based electrodes. In this study, Mo_1.33CT_x/carbon nanotubes (CNTs) electrodes of varying thicknesses were fabricated using a scalable doctor blade technique. Their electrochemical performance was studied in H₂SO₄, H₃PO₄, LiCl and KCl electrolytes using cyclic voltammetry and galvanostatic charge-discharge methods. Electrodes with an active material mass loading of 1.6 mg/cm² exhibited specific capacitances of 352, 287, 172, and 107 F/g in H₂SO₄, H₃PO₄, LiCl, and KCl electrolytes, respectively, at a scan rate of 2 mV/s. Increasing the mass loading of the electrode material to 3.5 mg/cm² resulted in a specific capacitance of 349, 260, 162 and 98 F/g in the same electrolytes. The incorporation of CNTs enabled rapid electrolyte ion transport throughout the electrode bulk, maintaining high capacitance values even at high scan rates. These results open new avenues for the development of high-performance electrode materials for supercapacitors.