NOVEL PROCESS FOR PREPARING SPINEL TYPE LITHIUM MANGANESE COMPOSITE OXIDE AND CATHODE ACTIVE MATERIAL FOR RECHARGEABLE BATTERY

摘要

There can be provided herein an improved process for preparing a spinel type of lithium manganese complex oxide which may be represented by the general formula (I)        Li_xMn_(2-y)M_y1B_y2O₄     (I)(wherein M is at least one menber selected from the group consisting of Al, Cr, Fe, Ni, Co, Ga and Mg, x is 0.9 ≦ x ≦ 1.1, y represents $\mathop{\mathrm{image}}$ {\text{y = y}}_{\text{1}}{\text{+ y}}_{\text{2}}$$, and y, y₁ and y₂ represent 0.002 ≦ y ≦ 0.5, 0 ≦ y₁ 0.5, 0.002 ≦ y₂ ≦ 0.1, respectively), andwhich may also be represented by the general formula (Ia) where y₂ in the above general formula (I) is 0        Li_xMn_(2-y)M_yO₄     (Ia)(wherein each of M and x has the same significance as the above, and y represents 0.002 ≦ y ≦ 0.5)and a positive electrode active material for a lithium ion secondary battery which comprises a spinel type of lithium manganese complex oxide which has made an improvememt in the charging and discharging characteristic property by this process.;The complex oxide prepared by the present invention is industrially very useful since it has an improved cycle characteristics, especially charging and discharging cycle characteristics at an elevated temperature (about 50 °C or more) that has not hitherto been achieved,