# US 12,770,862 B2 · Composite particle, positive electrode, all-solid-state battery, and method for producing composite particle

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- Number: US 12,770,862 B2
- Document ID: US12770862B2
- Status: Granted
- Kind: B2
- Application number: 18/100,235
- Filed: 2023-01-23
- Published: 2023-11-09
- Granted: 2026-10-20
- Earliest claimed: 2022-04-04
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Hideaki Watanabe; Masaru Kubota
- Web page: https://patentgrep.com/patent/US12770862B2

## CPC

- H01M 4/366: {as layered products}
- H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- H01M 4/525: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
- H01M 10/0562: Solid materials
- H01M 2004/028: {Positive electrodes}
- H01M 2300/0068: inorganic
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY

## Abstract

A composite particle includes a positive electrode active material particle and a coating film. The positive electrode active material particle contains a lithium-containing composite oxide having a layered rock salt structure, and the coating film covers at least a part of a surface of the positive electrode active material particle. The coating film contains a phosphate compound, and satisfies a relationship of the following formula (1): XP/T≥0.04 (1). In the above formula (1), XP indicates a mass fraction of phosphorus contained in the composite particle measured by inductively coupled plasma atomic emission spectroscopy, and T indicates a film thickness of the coating film measured by a scanning electron microscope.

## Claims

### Claim 1

A composite particle comprising a positive electrode active material particle and a coating film, wherein:
the positive electrode active material particle contains a lithium-containing composite oxide having a layered rock salt structure;
the coating film covers at least a part of a surface of the positive electrode active material particle;
the coating film contains a phosphate compound;
the composite particle comprises a coverage rate of 80% or more, wherein the coverage rate is measured by X-ray photoelectron spectroscopy;
the composite particle satisfies a relationship of the following formula (1): XP/T≥0.04 (1), where in the above formula (1),
XP indicates a mass fraction of phosphorus contained in the composite particle measured by inductively coupled plasma atomic emission spectroscopy, and
T indicates a film thickness of the coating film measured by a scanning electron microscope; and
the composite particle satisfies a relationship of the following formula (2): CLi/CP≤2.5 (2), where in the above formula (2),
CLi indicates elemental concentration of lithium obtained from a peak area of a Li1s spectrum measured by X-ray photoelectron spectroscopy, and
CP indicates elemental concentration of phosphorus obtained from a peak area of a P2p spectrum measured by the X-ray photoelectron spectroscopy.

### Claim 2 (depends on 1)

The composite particle according to claim 1, wherein the positive electrode active material particle has a D50 of 1 μm to 5 μm.

### Claim 3 (depends on 1)

The composite particle according to claim 1, wherein the coating film has a thickness from 1 nm to 100 nm.

### Claim 4 (depends on 1)

The composite particle according to claim 1, wherein:
the positive electrode active material particle has a D50 of 1 μm to 5 μm; and
the coating film has a thickness from 1 nm to 100 nm.

### Claim 5 (depends on 1)

The composite particle according to claim 1, wherein 1.0≤CLi/CP≤2.5.

### Claim 6 (depends on 1)

The composite particle according to claim 1, wherein the coating film does not contain lithium.

### Claim 7 (depends on 1)

A positive electrode comprising the composite particle according to claim 1 and a sulfide solid electrolyte.

### Claim 8 (depends on 7)

An all-solid-state battery comprising the positive electrode according to claim 7.

### Claim 9 (depends on 1)

A method for producing the composite particle of claim 1, the method comprising:
(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, wherein the coating solution contains a solute and a solvent.

### Claim 10 (depends on 9)

The method according to claim 9, wherein:
the solute contains the phosphate compound;
the coating solution satisfies a relationship of the following formula (3): 0≤nLi/nP≤1.5 (3); and
in the above formula (3),
nLi indicates molar concentration of lithium in the coating solution, and
nP indicates molar concentration of phosphorus in the coating solution.

### Claim 11 (depends on 9)

The method according to claim 9, wherein (b) includes forming the composite particle by a spray drying method.