Positive electrode active material and preparation method therefor, positive electrode sheet, battery and electric device

Patent metadata

Field	Value
Publication number	US-2025279415-A1
Application number	US-202519210813-A
Country	US
Kind code	A1
Filing date	May 16, 2025
Priority date	Feb 7, 2023
Publication date	Sep 4, 2025
Grant date	—

Abstract

A positive electrode active material and a preparation method therefor, a positive electrode sheet, a battery and an electric device. The positive electrode active material comprises: a core; and a carbon coating layer which covers at least part of the surface of the core, the molar ratio of sp 3 hybridized carbon atoms to sp 2 hybridized carbon atoms in the carbon coating layer being not less than 0.5.

First claim

What is claimed is:

1 . A positive electrode active material, comprising:
a core; and a carbon coating layer, the carbon coating layer covering at least part of the surface of the core; wherein a molar ratio of sp 2 hybridized carbon atoms to sp 3 hybridized carbon atoms in the carbon coating layer is not less than 0.5.

2 . The positive electrode active material according to claim 1 , wherein the core comprises a phosphate.

3 . The positive electrode active material according to claim 1 , wherein the core comprises LiMPO 4 , the M element comprising Mn and a non-Mn element.

4 . The positive electrode active material according to claim 3 , wherein the non-Mn element comprises one or two of a first doping element and a second doping element, the first doping element being doped at the manganese site, and the second doping element being doped at the phosphorus site.

5 . The positive electrode active material according to claim 4 , wherein the first doping element comprises one or more elements of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge.

6 . The positive electrode active material according to claim 4 , wherein the second doping element comprises one or more elements of B (boron), S, Si, and N.

7 . The positive electrode active material according to claim 3 , wherein the core comprises Li 1+x Mn 1-y A y P 1-z R z O 4 , wherein x is any value in the range of −0.100 to 0.100, y is any value in the range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, A comprises one or more elements of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, and Ge, and R comprises one or more elements of B (boron), S, Si, and N.

8 . The positive electrode active material according to claim 3 , wherein the core comprises Li 1+x C m Mn 1-y A y P 1-z R z O 4-n D n , wherein x is any value in the range of −0.100 to 0.100, y is any value in the range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, n is any value in the range of 0.001 to 0.1, m is any value in the range of 0.9 to 1.1, C comprises one or more elements of Zn, Al, Na, K, Mg, Nb, Mo, and W, A comprises one or more elements of Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb, and Ge, R comprises one or more elements of B (boron), S, Si, and N, and D comprises one or more elements of S, F, Cl, and Br.

9 . The positive electrode active material according to claim 1 , wherein the molar ratio of sp 2 hybridized carbon atoms to sp 3 hybridized carbon atoms in the carbon coating layer is not less than 0.8.

10 . The positive electrode active material according to claim 1 , wherein a thickness of the carbon coating layer is not greater than 10 nm.

11 . The positive electrode active material according to claim 1 , wherein a content of the carbon element in the positive electrode active material is not greater than 3 wt %.

12 . The positive electrode active material according to claim 1 , wherein a specific surface area of the positive electrode active material is not greater than 25 m 2 /g.

13 . The positive electrode active material according to claim 1 , wherein a median particle size of the positive electrode active material is not greater than 2 μm.

14 . The positive electrode active material according to claim 1 , wherein a powder resistivity of the positive electrode active material is not greater than 200 Ω·cm.

15 . A battery comprising a positive electrode plate, the positive electrode plate comprising a positive electrode current collector and the positive electrode active material layer according to claim 1 , wherein the positive electrode active material layer is located on one side of the positive electrode current collector.

16 . A method for preparing a positive electrode active material, comprising:
providing a core; and forming a carbon coating layer on at least part of the surface of the core, wherein a molar ratio of sp 2 hybridized carbon atoms to sp 3 hybridized carbon atoms in the carbon coating layer is not less than 0.5.

17 . The method according to claim 16 , wherein forming the carbon coating layer on at least part of the surface of the core comprises:
forming a pre-carbon coating layer on the surface of the core through a carbon source to obtain a pre-coated positive electrode active material; and performing a sintering treatment on the pre-coated positive electrode active material to form the carbon coating layer, thereby obtaining the positive electrode active material, wherein the carbon source comprises a first carbon source and a second carbon source.

18 . The method according to claim 17 , wherein:
the first carbon source comprises at least one of polyvinyl alcohol, polyethylene glycol, and citric acid; and the second carbon source comprises at least one of starch, sucrose, and glucose.

19 . The method according to claim 17 , wherein the first carbon source is a polymer, and a molecular weight of the first carbon source is not less than 1000.

20 . The method according to claim 16 , wherein forming the carbon coating layer on at least part of the surface of the core comprises:
mixing the core with the first carbon source, and performing a first sintering treatment to obtain a first coated positive electrode active material; and mixing the first coated positive electrode active material with the second carbon source, and performing a second sintering treatment to obtain the positive electrode active material.

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Jiang Yao
• Zhang Xinxin
• Ouyang Chuying
• Yuan Tianci
• Wang Zhiqiang
• Chen Shangdong
• Xu Bo

Classifications

• C01B25/45

  containing plural metal, or metal and ammonium · CPC title

• H01M10/0525

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

• H01M4/0471 Primary

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M2004/028

  Positive electrodes · CPC title