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The purpose of this investigation was the development of a new colloidal route for the fabrication of Mn₃O₄ electrodes for supercapacitors with enhanced charge storage performance. Mn₃O₄-carbon nanotube electrodes were fabricated with record-high capacitances of 6.67 F cm⁻² obtained from cyclic voltammetry tests at a scan rate of 2 mV s⁻¹ and 7.55 F cm⁻² obtained from the galvanostatic charge–discharge tests at a current density of 3 mA cm⁻² in 0.5 M Na₂SO₄ electrolyte in a potential window of 0.9 V. The approach involves the use of murexide as a capping agent for the synthesis of Mn₃O₄ and a co-dispersant for Mn₃O₄ and carbon nanotubes. Good electrochemical performance of the electrode material was achieved at a high active mass loading of 40 mg cm⁻² and was linked to a reduced agglomeration of Mn₃O₄ nanoparticles and efficient co-dispersion of Mn₃O₄ with carbon nanotubes. The mechanisms of murexide adsorption on Mn₃O₄ and carbon nanotube are discussed. With the proposed method, the time-consuming electrode activation procedure for Mn₃O₄ electrodes can be avoided. The approach developed in this investigation paves the way for the fabrication of advanced cathodes for asymmetric supercapacitors and multifunctional devices, combining capacitive, magnetic, and other functional properties.