Cathode properties of birnessite type manganese oxide prepared by using vanadium xerogel

Birnessite type manganese dioxides containing a small amount of vanadium were synthesized by oxidizing manganese nitrate with vanadium xerogel and hydrogen peroxide in a basic solution. When the nominal manganese/vanadium molar ratio was between 0.25 and 1, the resulting samples possessed birnessite type structure with irregular stacking of manganese dioxide layers, otherwise the products became amorphous. The obtained birnessite type manganese dioxides had a characteristic sponge-like and open-network microstructure composed of interconnected bent layer and the particle size was very small, less than 1 μm. The discharge capacity at the second cycle became maxima and reached 250 mAh g−1 for the sample prepared with the nominal Mn/V ratio of 1 and the cycling property was relatively good. The increase of utilization of active material due to the increase of electrical conductivity as the result of introduction of vanadium and/or the characteristic microstructure would lead the high discharge capacity. The irregular stacking of manganese oxide layers would be responsible for the relatively good cycling behavior.