The energy storage performance enhancement via electrochemical strategy for manganese oxide electrode in supercapacitors

Manganese oxides are widely studied due to their exceptionally high theoretical specific capacitance and environmentally friendly characteristics. This paper employs an electrooxidation strategy to enhance the energy storage performance of Mn3O4. The physical and electrochemical properties of the electrode material after multiple cycles are thoroughly investigated. The results demonstrate that, during the electrochemical oxidation process, Mn3O4 is converted to MnO2, accompanied by volumetric expansion and a morphological transition from microscopic particles to three-dimensional network structure. Notably, during this transformation, the internal resistance decreases progressively, which subsequently leads to an improvement in specific capacitance. Finally, an asymmetric supercapacitor device, MnOx//rGO, is fabricated and used to power a green LED, thereby exploring its practical application. The energy density of the MnOx//rGO asymmetric supercapacitor reaches 14.22 Wh kg-1 at a power density of 199.96 W kg-1, surpassing previously reported values.