Lithium-ion secondary battery, hybrid vehicle, electric vehicle, and plug-in hybrid vehicle

摘要

PROBLEM TO BE SOLVED: To provide a high-capacity positive electrode active material for a lithium ion secondary battery having excellent cycle characteristics. SOLUTION: A coating layer containing aluminum and a coating layer containing magnesium are provided on a surface layer portion of a positive electrode active material. The coating layer containing magnesium is present in a region closer to the surface of the particle than the coating layer containing aluminum. The coating layer containing aluminum can be formed by a sol-gel method using an aluminum alkoxide. The coating layer containing magnesium can be formed by segregating magnesium by mixing magnesium and fluorine as starting materials and heating after the sol-gel method. [Selection diagram] Figure 1