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. MnO2 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 MnO2 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.