关键词: 水热合成, 方铁锰矿, Mn₂O₃, 原位氧化还原沉淀

Abstract: The pure bixbyite Mn₂O₃ was prepared by first applying in-situ redox precipitation hydrothermal synthesis method under the very mild conditions, and characterized by XRD, TEM, BETand 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 Mn₂O₃ powder with a better morphology and distribution can be obtained. The average diameter of product is approximate to 80 nm. The normal LiMn₂O₄ spinel used as cathode material can be prepared using as synthesized bixbyite Mn₂O₃ as manganese precursor at 650 ℃ for 2 h by solid state reaction.

Key words: Hydrothermal synthesis, Bixbyite, Mn₂O₃, In-situ redox precipitation