Secondary battery, electrical device, positive active material and preparation method thereof, and positive electrode plate

Patent metadata

Field	Value
Publication number	US-2025329735-A1
Application number	US-202519212258-A
Country	US
Kind code	A1
Filing date	May 19, 2025
Priority date	Nov 29, 2023
Publication date	Oct 23, 2025
Grant date	—

Abstract

A secondary battery includes a positive electrode plate. The positive electrode plate includes a lithium-containing phosphate positive active particle. The lithium-containing phosphate positive active particle includes a center portion and a surface portion. The surface portion is continuously or discontinuously distributed on a surface of the center portion. A thickness of the surface portion is less than or equal to 10 nm. A lithium content of the center portion is greater than a lithium content of the surface portion.

First claim

What is claimed is:

1 . A secondary battery, comprising:
a positive electrode plate, wherein the positive electrode plate comprises a lithium-containing phosphate positive active particle, the lithium-containing phosphate positive active particle comprises a center portion and a surface portion, the surface portion is continuously or discontinuously distributed on a surface of the center portion, a thickness of the surface portion is less than or equal to 10 nm, and a lithium content of the center portion is greater than a lithium content of the surface portion.

2 . The secondary battery according to claim 1 , wherein:
an O—Fe—O stretching vibration peak is exhibited at a Raman shift of 200 cm −1 to 250 cm −1 in a Raman spectrum of the lithium-containing phosphate positive active particle; and/or an O—Fe—O bending vibration peak is exhibited at a Raman shift of 255 cm −1 to 300 cm −1 in a Raman spectrum of the lithium-containing phosphate positive active particle.

3 . The secondary battery according to claim 1 , wherein the surface portion comprises an iron oxide.

4 . The secondary battery according to claim 1 , wherein the surface portion comprises ferric oxide.

5 . The secondary battery according to claim 1 , wherein the lithium-containing phosphate positive active particle comprises Li 1+x M 1-y A y P 1-z R z O 4-t , wherein:
M comprises at least one of Fe, Co, or Ni; A comprises at least one of Mn, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, or Ge; R comprises at least one of B, S, Si, or N; and −0.1≤x≤0.1, 0≤y≤0.1, 0≤z≤0.1, and 0≤t≤0.1.

6 . The secondary battery according to claim 5 , wherein the lithium-containing phosphate positive active particle comprises Li 1+x1 Fe 1-y1 A y1 PO 4-t1 , wherein:
A comprises at least one of Mn, Al, Ti, V, Ni, or Zn; and 0≤x1≤0.05, 0≤y1≤0.05, and 0≤t1≤0.02.

7 . The secondary battery according to claim 1 , wherein a thickness of the surface portion is 1.5 nm to 4 nm.

8 . The secondary battery according to claim 1 , wherein a volume median diameter D v50 of the lithium-containing phosphate positive active particle is 300 nm to 10.5 μm.

9 . An electrical device, comprising the secondary battery according to claim 1 .

10 . A positive active material, comprising:
a substrate; and an oxide layer located on a surface of the substrate; wherein:
the substrate comprises Li 1+x M 1-y A y P 1-z R z O 4-t , wherein:
M comprises at least one of Fe, Co, or Ni;
A comprises at least one of Mn, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, or Ge;
R comprises at least one of B, S, Si, or N; and
−0.1≤x≤0.1, 0≤y≤0.1, 0≤z≤0.1, and 0≤t≤0.1; and

the oxide layer comprises an iron oxide.

11 . The positive active material according to claim 10 , wherein the substrate comprises Li 1+x1 Fe 1-y1 A y1 PO 4-t1 , wherein:
A comprises at least one of Mn, Al, Ti, V, Ni, or Zn; and 0≤x1≤0.05, 0≤y1≤0.05, and 0≤t1≤0.02.

12 . The positive active material according to claim 10 , wherein:
an O—Fe—O stretching vibration peak is exhibited at a Raman shift of 200 cm −1 to 250 cm −1 in a Raman spectrum of the positive active material; and/or an O—Fe—O bending vibration peak is exhibited at a Raman shift of 255 cm −1 to 300 cm −1 in a Raman spectrum of the positive active material.

13 . A positive electrode plate, comprising:
a positive current collector; and a positive active layer overlaying at least one surface of the positive current collector in a thickness direction of the current collector; wherein the positive active layer comprises a first active material, and the first active material comprises the positive active material according to claim 10 .

14 . The positive electrode plate according to claim 13 , wherein the positive active layer further comprises a second active material, and the second active material is different from the first active material.

15 . A secondary battery, wherein the secondary battery comprises the positive electrode plate according to claim 13 .

16 . A method for preparing a positive active material, comprising:
treating a substrate to form an oxide layer on a surface of the substrate; wherein:
the substrate comprises Li 1+x M 1-y A y P 1-z R z O 4-t , wherein:
M comprises at least one of Fe, Co, or Ni;
A comprises at least one of Mn, Zn, Al, Na, K, Mg, Mo, W, Ti, V, Zr, Fe, Ni, Co, Ga, Sn, Sb, Nb, or Ge;
R comprises at least one of B, S, Si, or N; and
−0.1≤x≤0.1, 0≤y≤0.1, 0≤z≤0.1, and 0.001≤t≤0.1; and

the oxide layer comprises an iron oxide.

17 . The preparation method according to claim 16 ,
wherein the substrate comprises Li 1+x1 Fe 1-y1 A y1 PO 4-t1 , wherein:
A comprises at least one of Mn, Al, Ti, V, Ni, or Zn; and
0≤x1≤0.05, 0≤y1≤0.05, and 0≤t1≤0.02;
the method further comprising:
oxidizing the substrate to form the oxide layer on the surface of the substrate.

18 . The preparation method according to claim 17 , wherein the substrate is oxidized by using an oxidizing gas;
optionally, the oxidizing gas comprises at least one of oxygen or ozone; and optionally, in the oxidizing gas, a sum of volumes of the oxygen and the ozone is 10% to 100% of a total volume of the oxidizing gas.

19 . The preparation method according to claim 18 , wherein, during the oxidization, a flow rate of the oxidizing gas is 200 sccm to 500 sccm; and
optionally, the oxidization is performed for a duration of 2 min to 60 min.

20 . The preparation method according to claim 17 , wherein the oxidization is performed at a temperature greater than or equal to 300° C.; and
optionally, the oxidization is performed at a temperature of 300° C. to 600° C.

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Wu Kai
• Liu Yukun
• Yuan Tianci
• Zhang Xinxin
• Wu Lingjing
• Kang Weibin
• Chen Shangdong

Classifications

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• B60L50/64

  Constructional details of batteries specially adapted for electric vehicles · CPC title

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title