Electrochemical preparation and supercapacitive performance of α-MnO2 nanospheres with secondary wall-like structures

A new approach has been proposed for the preparation of nanostructured alpha-MnO2. The method is based on the galvanostatic cathodic electrodeposition of the product from a nitrate bath under a direct current mode at a current density of 0.1 mA cm(-2). The intermediate product deposited in this stage is next thermally treated at 300 A degrees C for 3 h. To evaluate the properties of the final product, it was characterized by XRD and FTIR so as to gain information on its phase composition (which was found to be mainly alpha-MnO2) and SEM to gain information on its morphology (which was found to be nanospheres with secondary porous wall-like nanostructures). Additional electrochemical experiments on the product through cyclic voltammetry and charge-discharge tests revealed it to be capable of delivering high specific capacitance of 280 F g(-1), further its outstandingly long-term cycling stability which was only diminished to 95.4 % of the initial value after 1000 discharge cycles.