Synthesis of Li-Mn spinel oxide using Mn2O3 particles

Li-Mn spinel oxide cathode materials were prepared using Mn2O3 particles, which were derived from the thermal decomposition of Mn-acetate or Mn-oxalate particles. The effects of the molar ratio of Li/Mn and the reaction temperature on the produced phase were studied. From the lattice constant variation, it was found that the spinel oxides prepared by low-temperature reaction were cation deficient type. The cation deficiency decreased with an increase in the reaction temperature, due to the lowering in the oxidation potential. The temperature, in which the cation deficient degree attained was almost zero, was dependent on the molar ratio of Li/Mn and the kind of the Mn2O3 starting material. The higher temperature reaction produced spinel oxides with oxygen deficiency. The effect of the preparation conditions on the reversible Li-intercalation/deintercalation reaction was also examined from the view points of the structural deficiency. These experimental results implied that the defect structure in the Li-Mn spinel oxide is not always in the thermal equilibrium state, but depends on the other factors. (C) 1999 Published by Elsevier Science BN. All rights reserved.