Positive Electrode Active Material, Secondary Battery, and Method of Producing Positive Electrode Active Material

Patent metadata

Field	Value
Publication number	US-2025372641-A1
Application number	US-202519218763-A
Country	US
Kind code	A1
Filing date	May 27, 2025
Priority date	May 31, 2024
Publication date	Dec 4, 2025
Grant date	—

Abstract

A positive electrode active material comprises a lithium-metal composite oxide. The lithium-metal composite oxide is in a form of a plate-like particle. The plate-like particle satisfies relationships of “3≤dx/dz” and “2≤dy/dz”. “dx” represents a major-axis diameter of the plate-like particle. “dy” represents a minor-axis diameter of the plate-like particle. “dz” represents a thickness of the plate-like particle.

First claim

What is claimed is:

1 . A positive electrode active material comprising:
a lithium-metal composite oxide, wherein, the lithium-metal composite oxide is in a form of a plate-like particle, the plate-like particle satisfies relationships of 3≤dx/dz and 2≤dy/dz, dx represents a major-axis diameter of the plate-like particle, dy represents a minor-axis diameter of the plate-like particle, and dz represents a thickness of the plate-like particle.

2 . The positive electrode active material according to claim 1 , wherein the plate-like particle further satisfies a relationship of 0.21≤dy·dz≤0.29.

3 . The positive electrode active material according to claim 1 , wherein the lithium-metal composite oxide has a lamellar-rock-salt-type structure.

4 . The positive electrode active material according to claim 1 , wherein the lithium-metal composite oxide has a composition represented by a general formula:

where
a relationship of −0.5≤a≤0.5 is satisfied, and
M includes at least one selected from the group consisting of Ni, Co, Mn, and Al.

5 . The positive electrode active material according to claim 1 , wherein the plate-like particle consists of a single crystallite.

6 . A secondary battery comprising the positive electrode active material according to claim 1 .

7 . A method of producing a positive electrode active material, the method comprising:
(a) preparing a metal hydroxide; (b) mixing the metal hydroxide, a lithium compound, and a flux agent to form a mixture; and (c) performing heat treatment of the mixture in an oxygen atmosphere to synthesize a lithium-metal composite oxide, wherein the flux agent includes at least one selected from the group consisting of Li 2 SO 4 , NaCl, CaCl, LiCl, and LiNO 3 , and in the (c), the lithium-metal composite oxide grows into a plate-like particle.

8 . The method of producing a positive electrode active material according to claim 7 , wherein in the (b), a ratio of an amount of substance of the flux agent to an amount of substance of the metal hydroxide is from 0.1 to 1.

9 . The method of producing a positive electrode active material according to claim 7 , wherein
in the (c), a first heat treatment and a second heat treatment are performed in this order, a temperature in the second heat treatment is 1.2 to 1.4 times a temperature in the first heat treatment, and a duration of the second heat treatment is 0.1 to 0.5 times a duration of the first heat treatment.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ohsawa Ryosuke

Classifications

• H01M4/131

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

• H01M4/505

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

• C01G53/50

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

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