Highly defective Mn1-xO nanocrystals by anodic electrodeposition: Implication of high-rate capability electrochemical supercapacitors

COLL 485

Weifeng Wei, weifeng@ualberta.ca, Nasim Morawej, Weixing Chen, weixing.chen@ualberta.ca, and Douglas G. Ivey, doug.ivey@ualberta.ca. Department of Chemical & Materials Engineering, University of Alberta, 536, Chemical & Materials Engineering Building, Edmonton, AB T6G 2G6, Canada
Electrochemical supercapacitors (ESs) are well known to suffer from kinetic problems involving proton or alkaline metal cations intercalation, the conductivity of the electrolyte and the quality of electrolyte/electrode interfaces. To settle these technical issues for the manganese oxide ESs, we have applied complexing agents to manipulate the crystal structure of manganese oxides prepared by anodic electrodeposition. The as-deposited Mn1-xO nanocrystalline coatings have a defective rocksalt-type structure. Using these working electrodes, we demonstrate their distinct electrochemical properties, which combine high specific capacitance with high charge/discharge rate capacity. The striking enhancement of the rate capacity of the Mn1-xO coatings can be attributed to the structural transformation and morphological evolution induced preferentially at high cycling rate. It is expected that these experimental findings may provide some ideas to improve the electrochemical properties of the manganese oxide ESs.