Hierarchical Mn₂O₃ Nanoparticles with high Electrochemical performance

Manganese oxide valence states in the redox reactions prove advantageous in augmenting the electrochemical characteristics and thus enhance the supercapacitive performance of the material. In the present study, hierarchical Mn₂O₃ nanostructures are synthesized via facile autocombustion technique using various concentrations of classic biochemical Good’s buffer, and piperazine, and subsequently evaluated for their electrochemical performance.

The XRD study confirms the presence of crystalline Mn₂O₃. The SEM imaging confirmed that the amount of piperazine affects the shape, size, and morphology of the cuboidal Mn₂O₃. The Mn₂O₃ with 6 mM piperazine has the highest surface area (8.67758 m²/g). The electrochemical analysis performed in the three electrodes system was assessed in 1, and 6 M of KOH electrolytes using nickel foam. In cyclic voltammetry, 0 mM PIPES has the highest specific capacitance (608.05 F/g) at 1 mV/s scan rate at 1 M KOH electrolytes, and for 6 M KOH, 6 mM PIPES has the maximum specific capacitance (970.16 F/g). The charge-discharge curves for 0 mM piperazine have ~413 F/g, maximum, specific capacitance at 1 M KOH and 6 mM PIPES has ~808 F/g at 6 M KOH, maximum energy and power density are observed. This superior electrochemical performance of Mn₂O₃ is attributed to the high surface area and better coordination of Mn³⁺ ions in the presence of PIPES. Further enhancement in electrochemical performance is expected for the Mn₂O₃-rGo composite, which is under study.