# US 12,191,479 B2 · Negative electrode active material, negative electrode, and secondary battery

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- Number: US 12,191,479 B2
- Document ID: US12191479B2
- Status: Granted
- Kind: B2
- Application number: 17/507,476
- Filed: 2021-10-21
- Published: 2022-02-10
- Granted: 2025-01-07
- Earliest claimed: 2019-04-26
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Yasuhiro Ikeda
- Web page: https://patentgrep.com/patent/US12191479B2

## CPC

- H01M 4/364: {as mixtures}
- H01M 4/386: {Silicon or alloys based on silicon}
- H01M 4/587: for inserting or intercalating light metals
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/027: {Negative 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

A negative electrode active material includes a first negative electrode active material particle, and the first negative electrode active material includes a silicon-based material. A Si2p spectrum obtained by measuring the first negative electrode active material particle in a state of 0.6 V (vs. Li/Li+) by X-ray photoelectron spectroscopy has a peak in a range from 99.0 eV to 105.0 eV, and a half width of the peak is 1.5 eV or more and 8.0 eV or less.

## Claims

### Claim 1

A negative electrode active material comprising:
a first negative electrode active material particle including a silicon-based material having a silicon surface forming charge state,
wherein a Si2p spectrum obtained by measuring the first negative electrode active material particle by X-ray photoelectron spectroscopy has a peak in a range from 99.0 eV to 105.0 eV,
wherein a half width of the peak is 1.5 eV or more and 8.0 eV or less,
wherein the peak corresponds to the silicon surface forming charge state of the first negative electrode active material particle in a charged state of 0.6 V (vs. Li/Li+), and
wherein the charged state of 0.6 V (vs. Li/Li+) is based on a constant current charge at 0.05 C, thereafter a constant voltage charge at 0.6 V until a current value is 0.005 C.

### Claim 2 (depends on 1)

The negative electrode active material according to claim 1, wherein an X-ray diffraction pattern obtained by measuring the first negative electrode active material particle in the state of 0.6 V (vs. Li/Li+) by an X-ray diffraction method does not have a crystalline peak.

### Claim 3 (depends on 1)

The negative electrode active material according to claim 1, further comprising a second negative electrode active material particle including a carbon material.

### Claim 4 (depends on 2)

The negative electrode active material according to claim 2, further comprising a second negative electrode active material particle including a carbon material.

### Claim 5 (depends on 1)

A negative electrode comprising the negative electrode active material according to claim 1.

### Claim 6 (depends on 2)

A negative electrode comprising the negative electrode active material according to claim 2.

### Claim 7 (depends on 3)

A negative electrode comprising the negative electrode active material according to claim 3.

### Claim 8 (depends on 4)

A negative electrode comprising the negative electrode active material according to claim 4.

### Claim 9 (depends on 1)

A secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte,
wherein the negative electrode contains the negative electrode active material according to claim 1.

### Claim 10 (depends on 2)

A secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte,
wherein the negative electrode contains the negative electrode active material according to claim 2.

### Claim 11 (depends on 3)

A secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte,
wherein the negative electrode contains the negative electrode active material according to claim 3.

### Claim 12 (depends on 4)

A secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte,
wherein the negative electrode contains the negative electrode active material according to claim 4.