POSITIVE ELECTRODE ACTIVE MATERIAL AND BATTERY INCLUDING THE SAME

A positive electrode active material includes a first lithium composite oxide and a second lithium composite oxide that covers at least a part of the surface of the first lithium composite oxide. The first lithium composite oxide includes at least one selected from the group consisting of F, Cl, N, and S. The first lithium composite oxide has a crystal structure belonging to a layered structure. The second lithium composite oxide has a crystal structure belonging to space group Fd-3m. The positive electrode active material has an integrated intensity ratio I)/Iof greater than or equal to 0.05 and less than or equal to 0.90.