POSITIVE ELECTRODE ACTIVE MATERIAL, MIXTURE ELECTRODE HAVING THE SAME, POSITIVE ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a positive electrode active material for a lithium secondary battery, which has a high capacity and a practical load characteristic.SOLUTION: A positive electrode active material comprises a lithium complex oxide including at least manganese and nickel as transition metal, has a composition expressed by the formula (1), and satisfies the formula (2): Li[LiMnNiMe]O(1) (where Me represents at least one element selected from transition metals other than Mn and Ni, "a", "b", "c" and "d" satisfy the conditions given by 0c and 0≤d≤0.2); and 9.0≤Ni-Ni≤20.0(2) (where Nirepresents a nickel composition ratio (at%) in the whole lithium complex oxide; and Nirepresents a nickel composition ratio (at%) in a surface layer portion of the lithium complex oxide). FIG. 1 shows a SEM photograph (×5000) of the positive electrode active material.SELECTED DRAWING: Figure 1