公开(公告)号：US20230052866A1

公开(公告)日：2023-02-16

申请号：US17788844

申请日：2020-12-15

Applicant: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.

Inventor： Mayumi MIKAMI ,  Jo SAITO ,  Teruaki OCHIAI ,  Yohei MOMMA ,  Yoshimi NAKASHIMA ,  Yoshiharu ASADA ,  Kazuki TANEMURA

IPC: H01M4/525 ,  H01M10/0525 ,  H01M4/36

Abstract: A positive electrode active material having a crystal structure that is unlikely to be broken by repeated charging and discharging is provided. A positive electrode active material with high charge and discharge capacity is provided. A positive electrode active material including lithium, cobalt, nickel, magnesium, and oxygen, in which the a-axis lattice constant of an outermost surface layer of the positive electrode active material is larger than the a-axis lattice constant of an inner portion and in which the c-axis lattice constant of the outermost surface layer is larger than the c-axis lattice constant of the inner portion. A rate of change between the a-axis lattice constant of the outermost surface layer and the a-axis lattice constant of the inner portion is preferably larger than 0 and less than or equal to 0.12, and a rate of change between the c-axis lattice constant of the outermost surface layer and the c-axis lattice constant of the inner portion is preferably larger than 0 and less than or equal to 0.18.