Composite Fe₃O₄-MXene-Carbon Nanotube Electrodes for Supercapacitors Prepared Using the New Colloidal Method

MXenes, such as Ti₃C₂T_x, are promising materials for electrodes of supercapacitors (SCs). Colloidal techniques have potential for the fabrication of advanced Ti₃C₂T_x composites with high areal capacitance (C_S). This paper reports the fabrication of Ti₃C₂T_X-Fe₃O₄-multiwalled carbon nanotube (CNT) electrodes, which show C_S of 5.52 F cm^-2 in the negative potential range in 0.5 M Na₂SO₄ electrolyte. Good capacitive performance is achieved at a mass loading of 35 mg cm^-2 due to the use of Celestine blue (CB) as a co-dispersant for individual materials. The mechanisms of CB adsorption on Ti₃C₂T_X, Fe₃O₄, and CNTs and their electrostatic co-dispersion are discussed. The comparison of the capacitive behavior of Ti₃C₂T_X-Fe₃O₄-CNT electrodes with Ti₃C₂T_X-CNT and Fe₃O₄-CNT electrodes for the same active mass, electrode thickness and CNT content reveals a synergistic effect of the individual capacitive materials, which is observed due to the use of CB. The high C_S of Ti₃C₂T_X-Fe₃O₄-CNT composites makes them promising materials for application in negative electrodes of asymmetric SC devices.