Effect of Plating Solutions on Supercapacitor Characteristics of MnO2 Films
MnO2 films were electrodeposited on the Ti substrates by galvanostatic method in various plating solutions, which was MnCl2, Mn(NO3)2, MnSO4 and Mn(CH3COO)2 solutions, respectively. On X-ray diffraction test, Crystal structures of all MnO2 films were associated to α-MnO2 of tetragonal crystal system. Scanning electron microscopy results show that morphologies of MnO2 films were clearly different. Among them, MnO2 film prepared in Mn(CH3COO)2 solution presented a lot of cracks and holes. According to electrochemical impedance spectrum analysis, this MnO2 film presents the lowest charge-transfer resistance. Additionally, electrochemical active surface areas of MnO2 films were calculated on the basis of equivalent circuit model for impedance data. The result was found that MnO2 film prepared in Mn(CH3COO)2 solution showed the biggest electrochemical active surface area, which was about 382 cm2. Cyclic voltammograms were carried out for all the samples. MnO2 film formed in Mn(CH3COO)2 solution showed the highest special capacitance of 230 F g-1. The results suggest that Mn(CH3COO)2 solution is suitable for electrodepositing MnO2 film using supercapacitor electrode materials.
Zhenyu Du and X.B Sun
F. Xiao and Y. L. Xu, "Effect of Plating Solutions on Supercapacitor Characteristics of MnO2 Films ", Advanced Materials Research, Vols. 113-116, pp. 1810-1813, 2010