Patent ID: 11936041
Assignee: SK ON CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A lithium secondary battery, comprising:
a cathode formed from a cathode active material including a first cathode active material particle and a second cathode active material particle;
an anode; and
a separator interposed between the cathode and the anode,
wherein the first cathode active material particle includes a lithium metal oxide including nickel (Ni), manganese (Mn) and cobalt (Co), and the first cathode active material particle includes a continuous concentration gradient layer in at least one region between a central portion and a surface portion,
wherein the second cathode active material particle includes a lithium metal oxide including nickel (Ni), manganese (Mn) and cobalt (Co), and each of Ni, Mn and Co in the second cathode active material particle has a uniform composition from a central portion to a surface,
wherein a nickel concentration or a nickel molar ratio at every point of the first cathode active material particle is 0.77 to 0.83,
wherein a nickel concentration or a nickel molar ratio at every point of the first cathode active material particle is higher than that of the second cathode active material particle,
wherein a cobalt concentration or a cobalt molar ratio at every point of the first cathode active material particle is 0.07 to 0.13,
wherein a manganese concentration or a manganese molar ratio at every point of the first cathode active material particle is 0.07 to 0.121,
wherein the concentration gradient layer of the first cathode active material particle includes a continuous concentration gradient,
wherein the central portion has a constant concentration composition, and the central portion and the surface portion have different concentration compositions from each other through the concentration gradient layer,
wherein the surface portion includes a constant concentration region,
wherein in the first cathode active material particle, Ni has a continuously decreasing concentration in a direction from the central portion to the surface portion in the concentration gradient layer,
wherein in the first cathode active material particle, Co has a constant concentration from the central portion to the surface portion, and Mn has a continuously increasing concentration in a direction from the central portion to the surface portion in the concentration gradient layer,
wherein an average diameter (D50) of the first cathode active material particle is in a range from 3 μm to 15 μm,
wherein an average diameter (D50) of the second cathode active material particle is in a range from 7 μm to 15 μm, and
wherein a blending weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 4:6 to 1:9.