| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for processing a positive electrode active material for lithium ion secondary batteries which enables the suppression of the reaction between a positive electrode active material and an electrolytic solution, and the improvement in high-temperature shelf life.SOLUTION: A method for processing a positive electrode active material for lithium ion secondary batteries comprises: the first step of mixing a mixed process liquid prepared by mixing a first process liquid including a first solvent and a fluoride salt dissolved in the first solvent, and a second process liquid including a second solvent and an erbium salt dissolved in the second solvent with a positive electrode active material including a lithium-containing oxide; and the second step of baking the positive electrode active material after the first step at a temperature of 300-600°C. In the first step, the mixed process liquid and the positive electrode active material are mixed under the condition that no erbium fluoride is precipitated. In the second step, a quality-modified surface layer portion including F and Er elements is formed on the surface of the positive electrode active material. |
