# US 2022/0285673 A1 · Positive electrode active material particle and manufacturing method of positive electrode active material particle

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- Number: US 2022/0285673 A1
- Document ID: US20220285673A1
- Status: Published application
- Kind: A1
- Application number: 17/690,073
- Filed: 2022-03-09
- Published: 2022-09-08
- Earliest claimed: 2016-10-12
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Semiconductor Energy Laboratory Co., Ltd.
- Inventors: Takahiro KAWAKAMI; Teruaki OCHIAI; Yohei MOMMA; Ayae TSURUTA; Masahiro Takahashi; Mayumi MIKAMI
- Web page: https://patentgrep.com/patent/US20220285673A1

## CPC

- H01M 4/366: {as layered products}
- H01G 11/24: characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
- H01G 11/50: specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
- H01G 11/60: characterised by the solvent
- H01G 11/86: specially adapted for electrodes (carbonisation or activation of carbon for the manufacture of electrodes H01G11/34)
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- 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 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M 4/628: {Inhibitors, e.g. gassing inhibitors, corrosion inhibitors}
- 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
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

Provided is a positive electrode active material which suppresses a reduction in capacity due to charge and discharge cycles when used in a lithium ion secondary battery. A covering layer is formed by segregation on a superficial portion of the positive electrode active material. The positive electrode active material includes a first region and a second region. The first region exists in an inner portion of the positive electrode active material. The second region exists in a superficial portion of the positive electrode active material and part of the inner portion thereof. The first region includes lithium, a transition metal, and oxygen. The second region includes magnesium, fluorine, and oxygen.

## Claims

### Claim 1

A method comprising steps of:
analyzing a positive electrode active material comprising a composite oxide including lithium and cobalt by electron energy loss spectroscopy;
calculating a spectral intensity ratio of L3 level to L2 level of cobalt from a spectrum obtained by the analysis of the electron energy loss spectroscopy; and
determining that a number of divalent cobalt atoms exceeds a number of cobalt atoms exhibiting other valence from the spectral intensity ratio of L3 level to L2 level of cobalt,
wherein the analysis is performed at a depth of about 1 nm from a surface of the positive electrode active material.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the spectral intensity ratio of L3 level to L2 level of cobalt is larger than or equal to 3.8.

### Claim 3

A method comprising steps of:
analyzing each of first and second regions included in a positive electrode active material by electron energy loss spectroscopy, the first region including lithium and cobalt, the second region including magnesium, cobalt, and oxygen, and the second region being positioned outside of the first region;
calculating a spectral intensity ratio of L3 level to L2 level of cobalt in the first region from a spectrum obtained by the analysis of the electron energy loss spectroscopy;
determining that a number of trivalent cobalt atoms exceeds a number of cobalt atoms exhibiting other valence from the spectral intensity ratio of L3 level to L2 level of cobalt in the first region;
calculating a spectral intensity ratio of L3 level to L2 level of cobalt in the second region from a spectrum obtained by the analysis of the electron energy loss spectroscopy; and
determining that a number of divalent cobalt atoms exceeds a number of cobalt atoms exhibiting other valence from the spectral intensity ratio of L3 level to L2 level of cobalt in the second region.

### Claim 4 (depends on 3)

The method according to claim 3,
wherein the spectral intensity ratio of L3 level to L2 level of cobalt in the first region is less than 3.8, and
wherein the spectral intensity ratio of L3 level to L2 level of cobalt in the second region is larger than or equal to 3.8.