Method for producing composite particle, positive electrode, and all-solid-state battery, and composite particle, positive electrode, and all-solid-state battery

Patent metadata

Field	Value
Publication number	US-12592386-B2
Application number	US-202318104631-A
Country	US
Kind code	B2
Filing date	Feb 1, 2023
Priority date	Apr 26, 2022
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

A composite particle includes a positive electrode active material particle and a coating film. In a method for producing the composite particle, the coating film covers at least a part of a surface of the positive electrode active material particle, the coating film contains a phosphorus compound, and a glass-transition temperature of the coating film is 300° C. or less.

First claim

What is claimed is:

1 . A method for preparing a positive electrode slurry, the method comprising:
producing a composite particle, the composite particle comprising a positive electrode active material particle and a coating film, wherein producing the composite particle comprises:
(a) preparing a mixture by mixing a coating solution and the positive electrode active material particle; and
(b) producing the composite particle by drying the mixture by a spray drying method, wherein the coating solution contains a solute and a solvent, wherein the solute comprises a phosphorus compound comprising metaphosphoric acid,
wherein: the coating film covers at least a part of a surface of the positive electrode active material particle; a glass-transition temperature of the coating film is 300° C. or less; and dispersing the composite particle and a sulfide solid electrolyte in a dispersion medium.

2 . The method according to claim 1 , wherein:
the coating solution satisfies a relationship of the following formula (1): 0≤n Li /n P ≤1.1; and in the above formula (1), n Li indicates molar concentration of lithium in the coating solution, and n P indicates molar concentration of phosphorus in the coating solution.

3 . A method for producing a positive electrode, the method comprising:
(c) preparing a positive electrode slurry by the method according to claim 1 ; (d) forming a positive electrode active material layer by applying the positive electrode slurry to a surface of a positive electrode current collector; and (e) producing the positive electrode by rolling the positive electrode active material layer and the positive electrode current collector at 170° C. or higher.

4 . The method according to claim 3 , wherein in (e), the positive electrode active material layer having a filling rate of 90% or more is obtained.

5 . A method for producing an all-solid-state battery, the method comprising (f) producing the all-solid-state battery including the positive electrode produced by the method according to claim 3 .

6 . The method according to claim 1 , wherein:
the solute further comprises a lithium compound; and the coating solution satisfies a relationship of the following formula (1): 0<n Li /n P ≤1.1; wherein:
n Li indicates molar concentration of lithium in the coating solution; and
n P indicates molar concentration of phosphorus in the coating solution.

7 . The method of claim 6 , wherein the lithium compound comprises at least one of lithium hydroxide, lithium carbonate, or lithium nitrate.

8 . The method of claim 1 , wherein the solute further comprises sodium.

9 . The method of claim 1 , wherein:
the positive electrode active material particle is a secondary particle comprising a plurality of primary particles; and the secondary particle has a D50 of 1 μm to 50 μm.

10 . The method of claim 1 , wherein drying the mixture by the spray drying method comprises:
forming droplets of the mixture by spraying the mixture from a nozzle, wherein a diameter of the nozzle is from 0.1 mm to 10 mm; and drying the droplets with air at a temperature from 100° C. to 200° C. to produce the composite particle.

11 . The method of claim 10 , wherein the mixture has a solid content of from 10% to 30% by volume.

12 . The method of claim 10 , further comprising subjecting the composite particle to a heat treatment comprising:
a heat treatment temperature of 150° C. to 300° C.; and a heat treatment duration of from 1 hour to 10 hours.

13 . The method of claim 1 , wherein:
the solute further comprises sodium and a lithium compound comprising at least one of lithium hydroxide, lithium carbonate, or lithium nitrate; the coating solution satisfies a relationship of the following formula (1): 0<n Li /n P ≤1.1; wherein:
n Li indicates molar concentration of lithium in the coating solution; and
n P indicates molar concentration of phosphorus in the coating solution;
the mixture has a solid content of from 10% to 30% by volume; drying the mixture by the spray drying method comprises:
forming droplets of the mixture by spraying the mixture from a nozzle, wherein a diameter of the nozzle is from 0.1 mm to 10 mm; and
drying the droplets with air at a temperature from 100° C. to 200° C. to produce the composite particle; and
the method further comprises subjecting the composite particle to a heat treatment comprising:
a heat treatment temperature of 150° C. to 300° C.; and
a heat treatment duration of from 1 hour to 10 hours.

Assignees

• Toyota Motor Co Ltd

Inventors

• Watanabe Hideaki
• Kubota Masaru
• Furuya Ryosuke

Classifications

• H01M4/0435

  Rolling or calendering · CPC title

• H01M2004/021

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M2300/0068

  inorganic · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title