Synthesis of manganese dioxide nanosheets and charge storage evaluation.

Manganese oxide nanostructures were synthesized by chemical–electrochemical process using controlled-current electrochemical methods and heat-treatment. Manganese hydroxide precursor was prepared by electrogeneration of hydroxide (OH − ) at electrode surface from nitrate solution. MnO 2 hexagonal nanostructures were then achieved by heat annealing of the obtained precursor. A variety of characterization methods have been applied to the samples including Fourier transform infrared spectrometry, energy dispersive X-ray analysis, X-ray diffraction and scanning electron microscopy. The scanning electron micrographs showed that the product consists of nanosized disc-like structures with average diameter of 800 nm and thickness of 50 nm. The electrochemical properties of MnO 2 nanostructures were investigated by Cyclic Voltammetry. The maximum specific capacitance achieved was 204 F g −1 at a scan rate of 1 mV s −1 . [ABSTRACT FROM AUTHOR]