Lithium secondary battery

• US 10,644,306 B2
• Filed: 01/18/2019
• Issued: 05/05/2020
• Est. Priority Date: 01/18/2018
• Status: Active Grant

• Current Assignee: SK On Company Limited (SK Innovation Company Limited)
• Original Assignee: SK Innovation Company Limited
• Inventors: Do, Young Hoon, Cho, Yong Hyun, Kang, Min Gu, Kim, Soo Ho
• Primary Examiner(s): Jones, Robert S
• Assistant Examiner(s): Ojo-Amoo, Abibatu O
• Application Number:
  US16/251,446
• Publication Number:
  US 20190221830A1
• Time in Patent Office: 473 Days
• Field of Search: 429209
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

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.

Claims

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_xM1′

_aM2′

_bM3′

_cO_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_xM1_aM2_bM3_cO_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 (D₅₀) of the first cathode active material particle is in a range from 6 μ

m to 20 μ

m.

11. The lithium secondary battery according to claim 1, an average diameter (D₅₀) of the second cathode active material particle is in a range from 2 μ

m to 6 μ

m.