# US 10,319,993 B2 · Negative electrode for non-aqueous electrolyte secondary battery

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- Number: US 10,319,993 B2
- Document ID: US10319993B2
- Status: Granted
- Kind: B2
- Application number: 15/108,097
- Filed: 2014-12-19
- Published: 2016-11-10
- Granted: 2019-06-11
- Earliest claimed: 2013-12-26
- Assignees: Sanyo Electric Co., Ltd.
- Applicants: SANYO Electric Co., Ltd.
- Inventors: Na Wang; Shinji Kasamatsu; Yoshio Kato
- Web page: https://patentgrep.com/patent/US10319993B2

## CPC

- H01M 4/364: {as mixtures}
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/134: Electrodes based on metals, Si or alloys
- H01M 4/366: {as layered products}
- H01M 4/386: {Silicon or alloys based on silicon}
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/587: for inserting or intercalating light metals
- H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M 4/622: {being polymers}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/056: characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M 2004/027: {Negative electrodes}
- H01M 2300/002: Inorganic electrolyte
- 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

Gas evolution during the high-temperature storage of a non-aqueous electrolyte secondary battery is suppressed to improve the high-temperature storage characteristics of the non-aqueous electrolyte secondary battery. A negative electrode for a non-aqueous electrolyte secondary battery contains silicon-containing particles and graphite particles. A covering layer is disposed on each of the graphite particles. The covering layer contains a first covering material and a second covering material, the first covering material containing particles that can be made to swell with a non-aqueous electrolytic solution, the second covering material containing a water-soluble polymer material. The first covering material is disposed on a surface of each of the graphite particles. The mass ratio of the second covering material to the first covering material is higher than 1.

## Claims

### Claim 1

A negative electrode for a non-aqueous electrolyte secondary battery, the negative electrode comprising silicon-containing particles and graphite particles,
wherein a covering layer is disposed on each of the graphite particles,
the covering layer contains a first covering material and a second covering material, the first covering material containing particles that can be made to swell with a non-aqueous electrolytic solution, the second covering material containing a water-soluble polymer material,
the first covering material is disposed on a surface of each of the graphite particles,
a mass ratio of the second covering material to the first covering material in a negative electrode mixture is higher than 1,
wherein coverage of the graphite particles with the first covering material ranges from 10% to 50%, and
wherein the second covering material is disposed on a surface of the first covering material.

### Claim 2 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein a mass of the first covering material ranges from 0.1% to 5% of a mass of each of the graphite particles.

### Claim 3 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the covering layer has an average thickness in the range of 10 to 800 nm.

### Claim 4 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein the first covering material contains a styrene-butadiene rubber, and the second covering material contains carboxymethyl cellulose.

### Claim 5 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein a mass ratio of the silicon-containing particles to the graphite particles ranges from 1:99 to 20:80.

### Claim 6 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein a mass of the second covering material ranges from 1% to 5% of a mass of each of the graphite particles.

### Claim 7 (depends on 1)

The negative electrode for a non-aqueous electrolyte secondary battery according to claim 1, wherein that the covering layer has a thickness in the range of 10 to 400 nm.