Consequences of electrodeposition parameters on the microstructure and electrochemical behavior of electrolytic manganese dioxide (EMD) for supercapacitor

In this study, manganese dioxide (MnO2) was electrochemically synthesized on the surface of a lead anode using different current densities (100–300 A m−2) and deposition time (4–6 h). This work intends to highlight the consequences of various electrodeposition parameters via the electrochemical approach. The MnO2 electrowinning plant must consider the effect of electrodeposition parameters that can ensue on the overall impact of electrolytically derived MnO2 (EMD) powder on a larger scale. The micrographs of the obtained EMD powder revealed that spindle-like morphology was observed for the current density between 100 and 200 A m−2, whereas moss-like morphology was observed at a current density above 200 A m−2 with increased surface roughness. The deposition time has not shown a profound effect. This study highlights the EMD deposited at 200 A m−2 for 5 h when tested in 2 M NaOH electrolyte exhibits a storage performance of 98 F g−1. For broader adoption of this material, the asymmetric device comprising EMD versus activated carbon (EMD/AC) has been fabricated. The asymmetric supercapacitor is a key for storing energy, which delivered 36 F g−1 at energy and power densities of 10 Wh kg−1 and 2352 W kg−1, respectively. The further increase/decrease of current density and deposition time has a deleterious effect on the storage performance.