Galvanostatically electroplated MnO2 nanoplate-type electrode for potential electrochemical pseudocapacitor application

A manganese oxide (MnO2) nanoplate-type electrode has been prepared using galvanostatic electrodeposition method with an aqueous manganese sulfate solution and characterized for its structural, morphological, compositional, and surface wettability studies and afterward envisaged in pseudocapacitor applications. The MnO2, evidenced through Raman and X-ray photoelectron spectroscopy analysis, electrode composed of nanoplate-type surface morphology is hydrophilic and amorphous in nature. The electrochemical properties of MnO2 are examined using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy measurements in Na2SO4, NaOH, and KOH electrolytes, which demonstrate the pseudocapacitive signature with higher performance in Na2SO4 electrolyte than the others. A maximum specific capacitance of 804 F g(-1) at a scan rate of 5 mV s(-1) within -0.3-1.0 V potential range, with 84% retention after 1000 cycles, in 1 M Na2SO4 is evidenced.