Cathode active material, cathode for lithium secondary battery, and lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2025266429-A1
Application number	US-202519054091-A
Country	US
Kind code	A1
Filing date	Feb 14, 2025
Priority date	Feb 15, 2024
Publication date	Aug 21, 2025
Grant date	—

Abstract

A cathode active material includes a first active material and a second active material. The first active material includes an active material having an olivine structure, the second active material includes a lithium-rich oxide, and a weight of the first active material included in the cathode active material is greater than or equal to a weight of the second active material included in the cathode active material. Thereby, a cathode active material having improved overvoltage characteristics may be provided.

First claim

What is claimed is:

1 . A cathode active material comprising:
a first active material and a second active material, wherein the first active material includes an active material having an olivine structure, the second active material includes a lithium-rich oxide, and a weight of the first active material included in the cathode active material is greater than or equal to a weight of the second active material included in the cathode active material.

2 . The cathode active material of claim 1 , wherein a weight ratio of the first active material and the second active material included in the cathode active material is 65:35 to 85:15.

3 . The cathode active material of claim 1 , wherein an average particle diameter (D50) of the second active material is larger than an average particle diameter (D50) of the first active material.

4 . The cathode active material of claim 1 , wherein an average particle diameter (D50) of the first active material is 0.3 μm to 5 μm.

5 . The cathode active material of claim 1 , wherein an average particle diameter (D50) of the second active material is 2 μm to 9 μm.

6 . The cathode active material of claim 1 , wherein the first active material includes a carbon coating layer on a surface.

7 . The cathode active material of claim 6 , wherein the carbon coating layer is included in an amount of more than 0.25 wt % and less than 2 wt % based on a total weight of the cathode active material.

8 . The cathode active material of claim 1 , wherein the active material of the olivine structure is represented by chemical formula 1: LiMePO 4 , where Me is at least one element selected from the group consisting of Co, Ni, Fe, and Mn.

9 . The cathode active material of claim 1 , wherein the lithium-rich oxide is represented by chemical formula 2: Li a [M x Ni y Mn z ]O b , where M is at least one element selected from the group consisting of Co, Mg, Ti, Al, Fe, Ru, Zr, W, Sn, Sr, Nb, Mo, Cu, Zn, Cr, Ga, V, and Bi, 0≤x≤0.9, 0≤y≤0.9, x+y≥0, 0.1≤z≤0.9, 1.8≤a+x+y+z≤2.2, 1.05≤a/(x+y+z)≤1.95, and 1.8≤b≤2.2.

10 . The cathode active material of claim 1 , wherein the cathode active material is represented by chemical formula 3: Li a Ni b Mn c Fe d P e O f ,
wherein in the chemical formula 3, 1.002≤a≤1.196, 0.003≤b≤0.196, 0.6≤c≤0.649, 0.204≤d≤0.396, 0.51≤e≤0.99, and 3.02≤f≤3.98.

11 . A cathode for a lithium secondary battery comprising:
a cathode active material, wherein the cathode active material includes a first active material and a second active material, the first active material includes an active material having an olivine structure, the second active material includes lithium-rich oxide, and a weight of the first active material included in the cathode active material is greater than or equal to a weight of the second active material included in the cathode active material.

12 . The cathode for a lithium secondary battery of claim 11 , wherein a weight ratio of the first active material and the second active material included in the cathode active material is 65:35 to 85:15.

13 . The cathode for a lithium secondary battery of claim 11 , wherein an average particle diameter (D50) of the second active material is larger than an average particle diameter (D50) of the first active material.

14 . The cathode for a lithium secondary battery of claim 11 , wherein an average particle diameter (D50) of the first active material is 0.3 μm to 5 μm.

15 . The cathode for a lithium secondary battery of claim 11 , wherein an average particle diameter (D50) of the second active material is 2 μm to 9 μm.

16 . The cathode for a lithium secondary battery of claim 11 , wherein the first active material includes a carbon coating layer on a surface thereof.

17 . The cathode for a lithium secondary battery of claim 16 , wherein the carbon coating layer is included in an amount of more than 0.25 wt % and less than 2 wt % based on a total weight of the cathode active material.

18 . The cathode for a lithium secondary battery of claim 11 , wherein the active material of the olivine structure is represented by chemical formula 1: LiMePO 4 , where Me is at least one element selected from the group consisting of Co, Ni, Fe, and Mn.

19 . The cathode for a lithium secondary battery of claim 11 , wherein the lithium-rich oxide is represented by chemical formula 2: Li a [M x Ni y Mn z ]O b , where M is at least one element selected from the group consisting of Co, Mg, Ti, Al, Fe, Ru, Zr, W, Sn, Sr, Nb, Mo, Cu, Zn, Cr, Ga, V, and Bi, 0≤x≤0.9, 0≤y≤0.9, x+y≥0, 0.1≤z≤0.9, 1.8≤a+x+y+z≤2.2, 1.05≤a/(x+y+z)≤1.95, and 1.8≤b≤2.2.

20 . A lithium secondary battery comprising the cathode for a lithium secondary battery according to claim 11 .

Assignees

• Sk On Co Ltd

Inventors

• Beak Min Cheol
• Kang Min Suk
• Kang Hyun Sung
• Kim Seung Hyun
• Do Ji Yae
• Park Young Uk

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title