# US 2023/0411618 A1 · Negative electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

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- Number: US 2023/0411618 A1
- Document ID: US20230411618A1
- Status: Published application
- Kind: A1
- Application number: 18/037,419
- Filed: 2021-09-22
- Published: 2023-12-21
- Earliest claimed: 2020-11-30
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Yusuke Saito; Yosuke Sato; Naoki Seki
- Web page: https://patentgrep.com/patent/US20230411618A1

## CPC

- H01M 4/364: {as mixtures}
- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- H01M 4/48: of inorganic oxides or hydroxides
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- 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 for a non-aqueous electrolyte secondary battery includes composite particles containing a lithium silicate phase, a silicon phase dispersed in the lithium silicate phase, and a crystalline phase of silicon dioxide dispersed in the lithium silicate phase. The crystalline phase of silicon dioxide contains β-cristobalite and quartz.

## Claims

### Claim 1

A negative electrode active material for a non-aqueous electrolyte secondary battery, comprising:
composite particles containing
a lithium silicate phase,
a silicon phase dispersed in the lithium silicate phase, and
a crystalline phase of silicon dioxide dispersed in the lithium silicate phase, wherein the crystalline phase of silicon dioxide contains β-cristobalite and quartz.

### Claim 2 (depends on 1)

The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein
in an X-ray diffraction pattern of the composite particles obtained by X-ray diffractometry,
a peak attributed to the β-cristobalite appears around 2θ=21.6°, and
a peak attributed to the quartz appears around 2θ=26.3°.

### Claim 3 (depends on 2)

The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 2, wherein in the X-ray diffraction pattern of the composite particles, a ratio IA/IB of an intensity IA of the peak attributed to the β-cristobalite to an intensity IB of the peak attributed to the quartz is 0.1 or more.

### Claim 4 (depends on 1)

The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium silicate phase contains Li2Si2O5.

### Claim 5 (depends on 1)

The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium silicate phase contains at least one element selected from the group consisting of sodium, potassium, magnesium, barium, zirconium, niobium, a lanthanide element, tantalum, vanadium, titanium, phosphorus, bismuth, zinc, tin, lead, antimony, cobalt, fluorine, tungsten, aluminum, and boron.

### Claim 6 (depends on 1)

The negative electrode active material for a non-aqueous electrolyte secondary battery according to claim 1, wherein the silicon phase has a crystallite size of 10 nm or less.

### Claim 7 (depends on 1)

A non-aqueous electrolyte secondary battery, comprising:
a positive electrode: a negative electrode; and a non-aqueous electrolyte, wherein
the negative electrode includes the negative electrode active material for a non-aqueous electrolyte secondary battery of claim 1.