Patent ID: 11936036
Assignee: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 15:
16. A positive electrode active material comprising a positive electrode active material particle, the positive electrode active material comprising oxygen, cobalt, lithium, magnesium, titanium, nickel, and aluminum,
wherein a projection exists on a surface portion of the positive electrode active material particle,
wherein concentrations of magnesium, titanium and nickel in the projection are higher than concentrations of the magnesium, the titanium and the nickel in an inner portion of the positive electrode active material particle,
wherein a concentration of the aluminum in the surface portion is higher than a concentration of the aluminum in the inner portion and a concentration of aluminum in the projection, and
wherein the projection includes a first region and a second region where a concentration of fluorine in the first region is higher than in the second region.