Li-Mn spinel oxide cathode materials were prepared using Mn2O3 particles, w
hich were derived from the thermal decomposition of Mn-acetate or Mn-oxalat
e particles. The effects of the molar ratio of Li/Mn and the reaction tempe
rature on the produced phase were studied. From the lattice constant variat
ion, it was found that the spinel oxides prepared by low-temperature reacti
on were cation deficient type. The cation deficiency decreased with an incr
ease in the reaction temperature, due to the lowering in the oxidation pote
ntial. The temperature, in which the cation deficient degree attained was a
lmost zero, was dependent on the molar ratio of Li/Mn and the kind of the M
n2O3 starting material. The higher temperature reaction produced spinel oxi
des with oxygen deficiency. The effect of the preparation conditions on the
reversible Li-intercalation/deintercalation reaction was also examined fro
m the view points of the structural deficiency. These experimental results
implied that the defect structure in the Li-Mn spinel oxide is not always i
n the thermal equilibrium state, but depends on the other factors. (C) 1999
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