PREPARATION OF CATHODE MATERIALS FOR LITH IUM BATTERIES BY MELT IMPREGNATION METHOD .3. PREPARATION OF LITHIUM-MANGANESE COMPOSITE OXIDE, LI0.33MNO2, AS A 3V CATHODE MATERIAL

The chemical composition of new lithiated manganese oxide for a cathod e of secondary lithium batteries has been determined to be Li-0. 33MnO 2 by continous variation method. The pure Li0.33MnO2 was successful ly prepared by melt impregnation method. The preparation process was com posed of three heating steps, 1) heating the mixture of MnO2 with LiNO 3 (mole ratio of Li/Mn=1/3) at 260 degrees C for impregnation of melte d LiNO3 into the pore of MnO2. 2) heating at 300 degrees C for excludi ng NOx formed, and 3) finally heating at 320-350 degrees C depending o n the used MnO2 materials. Initial discharge capacity of Li0.33MnO2(21 0 mAh . g(-1)) is very close to its theoretical capacity calculated by its chemical composition (201 mAh . g(-1)). Stable rechargeable capac ity is around 170 mAh . g(-1) at 0.4 mA . cm(-2) (40mA . g(-1)) discha rge rate. Li0.33MnO2 prepared from CMO-U with high average pore radius shows higher discharge capacity and higher pore radius than those pre pared from HSA-EMD or 10-12.