| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material having high energy density at a high working voltage, a long cycle life, and no reduction in discharge capacity at a high temperature by dissolving Mg, Zn and Cr, Co, Fe, Ni or the like to a lithium manganese compound oxide, and baking the mixture in an oxidizing gas. SOLUTION: As a starting material, an oxide, hydroxide, carbonate, nitrate, or organic acid salt of a metal element constituting the general formula: Lix M<1> y M<2> z Mn2-y-z O4 is used. In the formula, M<2> represents one or more elements selected from Cr, Co, Ni, and Fe, M<1> represents an element other than M<2> except for Mn, such as Mg, Zn or the like which is capable of forming a divalent metal ion, (x), (y), and (z) where 0<x<=1.5, 0<=y<=0.5, 0<=z<=0.5, wherein y and z are not 0 at the same time. This starting material is baked at about 600-1000 deg.C in an oxidizing gas having an oxygen concentration of 50% or more for about 10-50 hours. Thus, the elements represented by M<1> and M<2> , Mn and oxygen are firmly bonded to prevent Mn from being dissolved into an electrolyte, even if a voltage is applied at a high temperature. |
