# US 11,909,033 B2 · Negative electrode including first layer having low compressive strength carbon active material and silicon active material and second layer having high compressive strength carbon active material and nonaqueous electrolyte secondary battery including the same

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- Number: US 11,909,033 B2
- Document ID: US11909033B2
- Status: Granted
- Kind: B2
- Application number: 16/982,284
- Filed: 2019-01-22
- Published: 2021-01-14
- Granted: 2024-02-20
- Earliest claimed: 2018-03-30
- Assignees: Panasonic Holdings Corporation; Panasonic Energy Co., Ltd.
- Applicants: Panasonic Corporation; SANYO Electric Co., Ltd.
- Inventors: Kouhei Tsuzuki; Yuki Morikawa; Hirokazu Wada; Yuta Matsuo; Kaori Ishikawa; Katsunori Yanagida
- Web page: https://patentgrep.com/patent/US11909033B2

## CPC

- H01M 4/366: {as layered products}
- 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 4/364: {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 2004/021: {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

In a nonaqueous electrolyte secondary battery, a negative electrode mix layer includes a first layer and a second layer disposed successively from a negative electrode collector. The first layer contains a first carbon-based active material having a 10% compressive strength of 3 MPa or less and a silicon-based active material containing Si. The second layer contains a second carbon-based active material having a 10% compressive strength of 5 MPa or more and has a lower content (mass ratio) of the silicon-based active material than the first layer.

## Claims

### Claim 1

A negative electrode for nonaqueous electrolyte secondary battery comprising a negative electrode collector and a negative electrode mix layer disposed on the negative electrode collector,
wherein the negative electrode mix layer includes a first layer and a second layer disposed successively from the negative electrode collector,
the first layer contains a first carbon-based active material having a 10% compressive strength of 3 MPa or less, and the first layer further contains a silicon-based active material containing Si, and
the second layer contains a second carbon-based active material having a 10% compressive strength of 5 MPa or more, and the second layer has a lower content of the silicon-based active material than the first layer,
wherein the first carbon-based active material constitutes a sole carbon-based active material in the first layer, and the second carbon-based active material constitutes a sole carbon-based active material in the second layer.

### Claim 2 (depends on 1)

The negative electrode for nonaqueous electrolyte secondary battery according to claim 1, wherein the second layer contains substantially no silicon-based active material.

### Claim 3 (depends on 1)

The negative electrode for nonaqueous electrolyte secondary battery according to claim 1, wherein the second carbon-based active material has a porosity of 1% to 5%.

### Claim 4 (depends on 1)

The negative electrode for nonaqueous electrolyte secondary battery according to claim 1, wherein the second carbon-based active material contains 1% to 5% by mass of amorphous component.

### Claim 5 (depends on 1)

The negative electrode for nonaqueous electrolyte secondary battery according to claim 1, wherein the thickness of the second layer is 20% to 70% of the thickness of the negative electrode mix layer.

### Claim 6 (depends on 1)

The negative electrode for nonaqueous electrolyte secondary battery according to claim 1, wherein a median diameter on a volume basis of the silicon-based active material is 0.5 times or less a median diameter on a volume basis of the first carbon-based active material.

### Claim 7 (depends on 1)

A nonaqueous electrolyte secondary battery comprising:
the negative electrode for nonaqueous electrolyte secondary battery according to claim 1;
a positive electrode;
a separator; and
a nonaqueous electrolyte.