Cathode properties of nanocrystalline manganese oxide synthesized through soft solution processing

Nanosized manganese oxide materials with zinc were prepared through a soft solution processing and the cathode properties for lithium batteries were investigated. The materials were prepared through a precipitation process by reduction of permanganate ions in an ethanol solution with controlled pH. X-ray diffraction studies showed that the materials were nanosized crystallites with diameter less than 3.4 nm and that the crystal structures of the compound varied from ε-MnO₂ phase to birnessite-like phase as pH increased. The Zn concentration in the nanocrystalline compound was controlled by the Zn/Mn molar ratio in the preparation solution. The zinc addition to the manganese oxide material improved the electrochemical properties. The cathode materials synthesized with optimized Zn concentration and pH showed a specific capacity of 100 mAh/g with a good cyclability between 1.5 and 3.9 V vs Li/Li⁺.