Lithium secondary battery

Patent metadata

Field	Value
Publication number	US-10644306-B2
Application number	US-201916251446-A
Country	US
Kind code	B2
Filing date	Jan 18, 2019
Priority date	Jan 18, 2018
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A lithium secondary battery comprises a cathode active material including a first cathode active material particle having a concentration gradient region and a second cathode active material particle having a single particle structure, to obtain improved electrical performance and mechanical stability.

First claim

What is claimed is:

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 a concentration gradient region between a central portion and a surface,
wherein the second cathode active material particle includes a lithium metal oxide having a single particle structure, and is represented by Chemical Formula 1, and a blending weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 8:2 to 1:9:
Li x M1′ a M2′ b M3′ c O y   [Chemical Formula 1]

wherein, in Chemical Formula 1, M1′, M2′ and M3′ are selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, W or B, M1′ includes Ni, M2′ includes Co, M3′ includes Mn, and 0<x≤1.1, 2≤y≤2.02, 0.7≤a≤0.9, 0.1≤b+c≤0.3 and a+b+c=1.

2. The lithium secondary battery according to claim 1 , wherein the single particle structure includes a single crystalline structure.

3. The lithium secondary battery according to claim 1 , wherein the first cathode active material particle includes a first metal having a concentration decreasing region between the central portion and the surface, and a second metal having a concentration increasing region between the central portion and the surface.

4. The lithium secondary battery according to claim 3 , wherein the first cathode active material particle further includes a third metal having a constant concentration from the central portion to the surface.

5. The lithium secondary battery according to claim 4 , wherein the first cathode active material particle is represented by Chemical Formula 2:
Li x M1 a M2 b M3 c O y   [Chemical Formula 2]

wherein, in Chemical Formula 2, M1, M2 and M3 each represents the first metal, the second metal and the third metal, and are selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga or B, and
0<x≤1.1, 2≤y≤2.02, 0<a<1, 0<b<1, 0<c<1, and 0<a+b+c≤1.

6. The lithium secondary battery according to claim 5 , wherein 0.6≤a≤0.95 and 0.05≤b+c≤0.4 in Chemical Formula 2.

7. The lithium secondary battery according to claim 5 , wherein 0.7≤a≤0.9 and 0.1≤b+c≤0.3 in Chemical Formula 2.

8. The lithium secondary battery according to claim 5 , wherein the first metal is nickel (Ni), the second metal is manganese (Mn) and the third metal is cobalt (Co).

9. The lithium secondary battery according to claim 1 , wherein a blending weight ratio of the first cathode active material particle and the second cathode active material particle is in a range from 8:2 to 6:4.

10. The lithium secondary battery according to claim 1 , an average diameter (D 50 ) of the first cathode active material particle is in a range from 6 μm to 20 μm.

11. The lithium secondary battery according to claim 1 , an average diameter (D 50 ) of the second cathode active material particle is in a range from 2 μm to 6 μm.

Assignees

• Sk Innovation Co Ltd

Inventors

• Do Young Hoon
• Cho Yong Hyun
• Kang Min Gu
• Kim Soo Ho

Classifications

• H01M4/485 Primary

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/505

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