# US 12,183,928 B2 · Positive electrode active material

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- Number: US 12,183,928 B2
- Document ID: US12183928B2
- Status: Granted
- Kind: B2
- Application number: 17/450,286
- Filed: 2021-10-08
- Published: 2022-04-14
- Granted: 2024-12-31
- Earliest claimed: 2020-10-12
- Assignees: Honda Motor Co., Ltd.
- Applicants: Honda Motor Co., Ltd.
- Inventors: Kazuyuki Sato; Takeshi Fujino
- Web page: https://patentgrep.com/patent/US12183928B2

## CPC

- H01M 4/628: {Inhibitors, e.g. gassing inhibitors, corrosion inhibitors}
- 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 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/028: {Positive electrodes}
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

To provide a positive electrode active material capable of improving cycle characteristics of a lithium ion secondary battery and achieving a desirable discharge capacity. A positive electrode active material that is an aggregate of lithium compounds each including a lithium-containing transition metal oxide, includes particles having a surface on which a solid film including a plurality of types of lithium salts is formed. The solid film preferably includes a fluorine compound and a phosphorus compound. The solid film preferably contains 70 mol % or more of fluorine atoms with respect to the total number of moles of the fluorine atoms and phosphorus atoms.

## Claims

### Claim 1

A positive electrode active material that is an aggregate of lithium compounds each comprising a lithium-containing transition metal oxide,
the positive electrode active material comprising particles having a surface on which a solid film comprising lithium fluoride (LIF) and lithium metaphosphate (LIPO3) is formed,
the solid film having a thickness of 30 nm or more and 70 nm or less,
wherein the thickness of the solid film means a maximum thickness of the solid film with respect to the surface of the particles of the positive electrode active material when a perpendicular line is drawn to a center of the positive electrode active material, and
wherein the solid film contains 70 mol % or more of fluorine atoms with respect to a total number of moles of the fluorine atoms and phosphorus atoms.

### Claim 2 (depends on 1)

The positive electrode active material according to claim 1, wherein the lithium-containing transition metal oxide comprises 60 mol % or more of nickel atoms with respect to transition metal.

### Claim 3

A positive electrode active material that is an aggregate of lithium compounds each comprising a lithium-containing transition metal oxide,
the positive electrode active material comprising particles having a surface on which a solid film comprising lithium fluoride (LIF) and lithium metaphosphate (LIPO3) is formed,
the solid film having a thickness of 30 nm or more and 70 nm or less,
wherein the thickness of the solid film means a maximum thickness of the solid film with respect to the surface of the particles of the positive electrode active material when a perpendicular line is drawn to a center of the positive electrode active material, and
wherein a molar ratio of fluorine atoms to phosphorus atoms is greater than a molar ratio of the phosphorus atoms to the fluorine atoms, in the solid film formed in a recess of the surface of the particles of the positive electrode active material.

### Claim 4 (depends on 3)

The positive electrode active material according to claim 3, wherein the lithium-containing transition metal oxide comprises 60 mol % or more of nickel atoms with respect to transition metal.