Chronoamperometric versus galvanostatic preparation of manganese oxides for electrochemical capacitors

Chronoamperometric and galvanostatic methods of manganese dioxide electrodeposition have been compared in this work for their ability to produce high specific capacitance manganese dioxide electrodes for supercapacitor applications. When directly compared in terms of the charge passed (and hence the mass of manganese dioxide deposited) and the timeframe of electrodeposition, chronoamperometry most often led to superior performing electrodes. In the best case, an electrode was prepared that attained 2986 F/g. The results of this work were interpreted in terms of the manganese dioxide deposition mechanism and its impact on deposit morphology. Furthermore, it was concluded that the loss of charge during electrodeposition, as either the result of Mn3+ intermediate species diffusing away from the electrode, or the competing oxygen evolution process, significantly influenced the ability to estimate the amount of manganese dioxide prepared.