Synthesis of manganese dioxide from some manganese(II) salts and ammonium nitrate

Manganese dioxides were obtained from heating manganese(II) salts (nitrate, carbonate and acetate) and ammonium nitrate at 250 degreesC for 1 h. The formation of gamma -MnO2 phase was confirmed by X-ray diffraction. The particle sizes and specific surface areas of the products were 0.2-1 mum and 170-190 m(2) g(-1), respectively. When the products were used as the cathode materials of lithium manganese oxide cells, the discharge capacities of these cells were 240-255 mAh g(-1), which were higher than that of the cell using electrolytic manganese dioxide (207 mAh g(-1)). It was found that the products by the simple process are hopeful as a cathode material.