POSITIVE ELECTRODE MATERIAL FOR LITHIUM SECONDARY BATTERY, ITS MANUFACTURING METHOD, POSITIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To suppress drop in initial capacity and to obtain high battery characteristics under high temperature by including less than a specified ratio of an alkaline metal excluding lithium and/or an alkaline earth metal in a lithium manganese composite oxide. SOLUTION: A positive electrode material for a lithium secondary battery contains less than 10 mol.% of alkaline metal excluding lithium and/or alkaline earth metal (metal element M) against the mole of manganese. The performance of the lithium manganese composite oxide degrades at high temperature, one reason of which is elution of manganese from the lithium manganese composite oxide. This elution can be retarded by including less than 10 mol.%, preferably 0.01 mol.% of the metal element M against the mole of the manganese. The metal element M is preferably cesium, and uneven distribution of this element near the active material is preferable. This material can be used as an active material in the positive electrode for the lithium secondary battery.