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

Claim 0:
1. A positive electrode active material comprising a positive electrode active material particle, the positive electrode active material comprising oxygen, cobalt, lithium, magnesium, titanium, and nickel,
wherein a depression exists at a surface portion of the positive electrode active material particle and the titanium exists on or in part of an inner wall of the depression,
wherein a projection exists on the surface portion,
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, 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.