Influence of cation (NH4+) on electrochemical characteristics of MnO2 nanowire synthesized by hydrothermal method

Nanowires of MnO2 were prepared by a simple method in which the commercial granular gamma-MnO2 powders were hydrothermally treated in water or ammonia solution at 150 degrees C. These 1D nanostructured manganese oxides were characterized physically by X-ray diffraction, scanning electron microscopy and transmission electron microscopy tests. Cyclic voltammetry and constant current discharge experiments were employed to explore the diversity of electrochemical performances; and the reasons for the difference are discussed. The experimental results indicate that the existence of NH4+ in the preparation solution has depressed the electrochemical performances of the final product; This is further confirmed by the electrochemical impedance spectra of the electrodes.