Supercapacitive performance of electrochemically synthesized nanocrystalline MnO2 films using different plating solutions: A comparative study

In this paper we report the comparative supercapacitive performance of the electrodeposited MnO2 films prepared using different plating solutions, namely KMnO4, MnSO4 and Mn(CH3COO)(2). All the MnO2 films possess the hexagonal phase of epsilon manganese dioxide (epsilon-MnO2, akhtenkite), consistent with the JCPDS card no. 12-0141. The analyses of SEM images reveal that the electrodeposited MnO2 film prepared from the plating solution KMnO4 has a porous microstructure comprising of sparsely distributed grains, whereas that prepared from MnSO4 has a uniform morphology covered with nanofibers having porous spaces between them, and that prepared using Mn(CH3COO)(2) exhibits a dense morphology comprising of nanofibres. The galvanostatic charge/discharge measurements show the maximum specific capacitance 325.6 F/g for the MnO2 film prepared using KMnO4, followed by 275.2 F/g and 174.5 F/g for the films prepared by MnSO4 and Mn(CH3COO)(2)., respectively. The variation in specific capacitances of the films is attributed to varying morphological features of the films. (X) 2018 Elsevier B. V. All rights reserved