Pressure-resistant positive active material and electrochemical energy storage apparatus

Patent metadata

Field	Value
Publication number	US-12451485-B2
Application number	US-201917416122-A
Country	US
Kind code	B2
Filing date	Nov 25, 2019
Priority date	Dec 27, 2018
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

This application relates to the field of battery technologies, and in particular, to a pressure-resistant positive active material and an electrochemical energy storage apparatus. The positive active material includes secondary particles composed of primary particles, and a quantity σ of primary particles per unit sphere area in a SEM graph of the secondary particles is 5/μm2 to 30/μm2. A single-particle pressure-resistant strength of the secondary particles is 60 MPa to 300 MPa. A molecular formula of the positive active material is LixNiyCozMkMepOrAm, where 0.95≤x≤1.05, 0≤y≤1, ≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤2, 0≤m≤2, and m+r≤2. The positive active material in this application has a compact particle structure and a high single-particle pressure-resistant strength.

First claim

What is claimed is:

1. A positive active material, wherein the positive active material comprises secondary particles composed of primary particles, the secondary particles have D v 10 of 2 μm to 8 μm, D v 50 of 5 μm to 18 μm, and D v 90 of 10 μm to 30 μm, the primary particles are rod-shaped, cone-shaped, or needle-shaped and have an average length of 200 nm to 1000 nm and an average radial cross-sectional width of 150 nm to 400 nm, an average quantity σ of primary particles per unit sphere surface area in a SEM profile of the secondary particles is 5/μm 2 to 30/μm 2 , and a single-particle pressure-resistant strength of the secondary particles is 150 MPa to 300 MPa; and
a molecular formula of the positive active material is Li x Ni y CO z M k Me p O r A m , wherein 0.95≤x≤1.05, 0≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤2, 0≤m≤2, and m+r≤2, M is selected from Mn and/or Al, Me is selected from any one or a combination of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from any one or a combination of N, F, S, and Cl, wherein an outer coating layer is provided on a surface of the positive active material, and an inner coating layer is provided on the surface of at least a portion of the primary particles at non-outermost positions of the secondary particles,
wherein the inner coating layer comprises a coating element selected from any one or a combination of Ba, Zn, W, Y, and P, and the inner coating layer is 0.01% to 0.5% by weight of the positive active material,
wherein the outer coating layer is a composite form of a continuous first coating layer and a discontinuous second coating layer, wherein the continuous first coating layer comprises an oxide of a coating element selected from any one or a combination of W, Y, Si, B, P and Sn, and wherein the discontinuous second coating layer comprises an oxide of a coating element selected from any one or a combination of Zn, and Co, and the outer coating layer is 0.01% to 0.5% by weight of the positive active material;
wherein a powder compacted density of the positive active material is not less than 3.3 g/cm 3 .

2. The positive active material according to claim 1 , wherein in the molecular formula of the positive active material, 0.70≤y≤0.95, 0≤z≤0.2, 0≤k≤0.2, and 0≤p≤0.05.

3. The positive active material according to claim 1 , wherein the secondary particles are obtained by stacking the primary particles in an extension direction of the primary particles.

4. The positive active material according to claim 1 , wherein the secondary particles have a BET of 0.3 m 2 /g to 0.8 m 2 /g.

5. An electrochemical energy storage apparatus, comprising the positive active material according to claim 1 .

6. The positive active material according to claim 1 , wherein a ratio of a length to a radial cross-sectional width of the primary particles is 2 to 10.

7. The positive active material according to claim 1 , wherein a substance of the discontinuous second coating layer is different from a substance of the continuous first coating layer.

8. The positive active material according to claim 1 , wherein the length of the primary particles is 300 nm to 1000 nm.

9. The positive active material according to claim 1 , wherein the length of the primary particles is 500 nm to 1000 nm.

10. The positive active material according to claim 1 , wherein the radial cross-sectional width of the primary particles is 200 nm to 400 nm.

11. The positive active material according to claim 1 , wherein a ratio of the length to the radial cross-sectional width of the primary particles is 2-5.

12. A method comprising:
preparing a positive active material, wherein the positive active material comprises secondary particles composed of primary particles, the secondary particles have D v 10 of 2 μm to 8 μm, D v 50 of 5 μm to 18 μm, and D v 90 of 10 μm to 30 μm, the primary particles are rod-shaped, cone-shaped, or needle-shaped and have an average length of 200 nm to 1000 nm and an average radial cross-sectional width of 150 nm to 400 nm, an average quantity σ of primary particles per unit sphere surface area in a SEM profile of the secondary particles is 5/μm 2 to 30/μm 2 , a single-particle pressure-resistant strength of the secondary particles is 150 MPa to 300 MPa, the secondary particles have a BET of 0.3 m 2 /g to 0.8 m 2 /g, a molecular formula of the positive active material is Li x Ni y CO z M k Me p O r A m , wherein 0.95≤x≤1.05, 0≤y≤1, 0≤z≤1, 0≤k≤1, 0≤p≤0.1, 1≤r≤2, 0≤m≤2, and m+r≤2, M is selected from Mn and/or Al, Me is selected from any one or a combination of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Sr, Sb, Y, W, and Nb, and A is selected from any one or a combination of N, F, S, and Cl, and a powder compacted density of the positive active material is not less than 3.3 g/cm 3 ,
forming, on a surface of at least a portion of the primary particles at non-outermost positions of the secondary particles, an inner coating layer, wherein the inner coating layer comprises a coating element selected from any one or a combination of Ba, Zn, W, Y, and P, and the inner coating layer is 0.01% to 0.5% by weight of the positive active material, and
forming, on a surface of the positive active material, an outer coating layer, wherein the outer coating layer is a composite form of a continuous first coating layer and a discontinuous second coating layer, wherein the continuous first coating layer comprises an oxide of a coating element selected from any one or a combination of W, Y, Si, B, P and Sn, and
wherein the discontinuous second coating layer comprises an oxide of a coating element selected from any one or a combination of Zn, and Co, and the outer coating layer is 0.01% to 0.5% by weight of the positive active material.

13. The positive active material according to claim 1 , wherein the average length of the primary particles is of 500 nm to 1000 nm, and the average radial cross-sectional width of the primary particles is of 350 nm to 400 nm.

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Du Rui
• Liu Yongchao
• Zhao Deyu
• Wang Sihui
• Shen Chongheng
• Liu Na

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/021

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

• H01M10/0525

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

• H01M4/366

  as layered products · CPC title

• H01M4/131

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