Excellent Electrochemical Performance of Air Plasma‐Treated CoMn ₂ O ₄ Electrode for Supercapacitors

Abstract Cobalt manganese oxide (CoMn 2 O 4 ) material production and characterization are presented in this work in preparation for their possible application in supercapacitors. The synthesis process used is a top‐down solid‐state strategy that is both economical and environmentally benign. After 500 °C post‐calcination, phase purity is verified by X‐ray diffraction (XRD) analysis. In the CoMn 2 O 4 , significant metal oxide vibrational modes are shown by Fourier transform infrared spectroscopy (FTIR). Raman spectroscopy is used to characterize structure, through elemental color mapping, energy‐dispersive X‐ray spectroscopy (EDX), and field emission scanning electron microscopy (FE‐SEM), researchers analyze morphological characteristics. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) experiments distinctly demonstrate that plasma treatment enhances the material properties including intensity, bending vibrations, morphology, and capacitance. After being exposed to air plasma, the resultant CoMn 2 O 4 shows a notable capacitance of 961 F/g at 0.5 mA/g in a 2 M KOH electrolyte. These findings together suggest that CoMn 2 O 4 has potential as an electrode material for supercapacitor research.