The pure bixbyite Mn 2O 3 was prepared by first applying in situ redox precipitation hydrothermal synthesis method under the very mild conditions, and characterized by XRD, TEM, BET and TGA. The effects of alkalinity, crystallization time and temperature on the product were investigated. The results demonstrated that the alkalinity has an obvious effect on the product whereas the crystallization time and temperature has only a little influence on the product. Too low alkalinity results in no formation of product, and too high alkalinity leads to no formation of pure product with a smaller particle size. Under optimized conditions, the pure bixbyite Mn 2O 3 powder with a better morphology and distribution can be obtained. The average diameter of product is approximate to 80 nm. The normal LiMn 2O 4 spinel used as cathode material can be prepared using as synthesized bixbyite Mn 2O 3 as manganese precursor at 650 ℃ for 2 h by solid state reaction.
