Characterization and electrochemical performance of Mn-doped Co3O4 nanoparticles for supercapacitor applications

The innovative investigation into Mn:Co₃O₄ samples through a multifaceted approach encompassing diverse characterization methodologies and electrochemical assessments. Employing X-ray diffraction, we unveiled the internal geometry and crystallite disposition, which impeccably matched the spinel-cubic structure of Co₃O₄. X-ray photoelectron spectroscopy analysis meticulously corroborated the existence of Co, Mn, and O elements while unveiling distinctive valence states for Co and Mn ions. On further analysis, scanning electron microscopy provides a visual insight into granular, hexagonal-shaped layered structures, with varying pore abundance among the all temperatures. The compositional integrity is confirmed through energy-dispersive X-ray spectroscopy. Electrochemical investigations encompass cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The CV curves exhibit redox peaks denoting pseudo-capacitive behavior, while GCD profiles display symmetric behavior. The specific capacitance at various scan rates highlights the superior performance of the Mn:Co₃O₄ sample at 700 °C. EIS analyses affirm low interfacial charge resistance and accelerated ion diffusion. Cyclic stability assessment over 1500 cycles underscores the enduring process of Mn:Co₃O₄ culminating in a favorable specific capacitance of 625 F/g and a remarkable capacity retention of 96% even after 1500 cycles.