Synthesis, characterization, and supercapacitor studies of manganese (IV) oxide nanowires

One-dimensional manganese (IV) oxide (MnO2) (∼20 nm in average diameter) were synthesized by cathodic electrodeposition and heat treatment. The mechanism of electrodeposition and nanowire formation were discussed. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR). Nanowires with varying lengths and diameters were found in TEM and SEM images of the sample. The results of N2 adsorption–desorption analysis indicated that the BET surface area of the MnO2 nanowires was 157 m2 g−1 and the pore size distributions were 2.5 and 4.5 nm. The electrochemical performances of the prepared MnO2 as an electrode material for supercapacitors were evaluated by cyclic voltammetry and galvanostatic charge/discharge measurements in a solution of 0.5 M Na2SO4. The higher specific capacitance of 318 F g−1 and good capacity retention of 86% were achieved after 1000 charge–discharge cycles had been observed for the MnO2 nanowires electrode.