# US 12,015,143 B2 · Method of manufacturing negative electrode for secondary battery

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- Number: US 12,015,143 B2
- Document ID: US12015143B2
- Status: Granted
- Kind: B2
- Application number: 17/292,544
- Filed: 2020-01-16
- Published: 2022-01-06
- Granted: 2024-06-18
- Earliest claimed: 2019-01-18
- Assignees: LG Energy Solution, Ltd.
- Applicants: LG Energy Solution, Ltd.
- Inventors: Ye Ri Kim; Sang Wook Woo; Oh Byong Chae
- Web page: https://patentgrep.com/patent/US12015143B2

## CPC

- H01M 4/1393: of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/0404: {by coating on electrode collectors}
- H01M 4/0459: {Electrochemical doping, intercalation, occlusion or alloying}
- 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 4/1395: of 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 4/587: for inserting or intercalating light metals
- H01M 4/621: {Binders}
- H01M 10/052: Li-accumulators
- 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 method of manufacturing a negative electrode for a secondary battery. The method includes forming a first negative electrode active material layer including a carbon-based active material on at least one surface of a negative electrode current collector; and forming a second negative electrode active material layer including a silicon-based active material on a surface of the first negative electrode active material opposite the negative electrode current collector, wherein the silicon-based material is intercalated with lithium by pre-lithiation on the first negative electrode active material layer.

## Claims

### Claim 1

A method of manufacturing a negative electrode for a secondary battery, comprising:
pre-lithiating a silicon-based active material to obtain a pre-lithiated silicon-based active material having lithium intercalated into the silicon-based active material, wherein the pre-lithiating is performed by placing a mesh-type copper electrode and a glassy carbon electrode into a pre-lithiation solution, wherein the pre-lithiation solution comprises a lithium salt and an organic solvent;
adding the silicon-based active material to the pre-lithiation solution containing the mesh-type copper electrode and the glassy carbon electrode; and
intercalating lithium into the silicon-based active material by performing an oxidation/reduction reaction in the pre-lithiation solution;
forming a first negative electrode active material layer comprising a carbon-based active material on at least one surface of a negative electrode current collector; and
forming a second negative electrode active material layer comprising the pre-lithiated silicon-based active material on a surface of the first negative electrode active material layer opposite the negative electrode current collector.

### Claim 2 (depends on 1)

The method of claim 1, wherein the oxidation/reduction reaction is performed by applying a current to the mesh-type copper electrode and the glassy carbon electrode at a rate of 0.001 C to 5 C.

### Claim 3 (depends on 1)

The method of claim 1, wherein the oxidation/reduction reaction is performed at 5° C. to 40° C.

### Claim 4 (depends on 1)

The method of claim 1, wherein the carbon-based active material comprises at least one selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, acetylene black, Ketjen black, graphene, and fibrous carbon.

### Claim 5 (depends on 1)

The method of claim 1, wherein the carbon-based active material has an average particle diameter (D50) of 5 μm to 35 μm.

### Claim 6 (depends on 1)

The method of claim 1, wherein the silicon-based active material comprises a compound represented by the following Formula 1:
SiOx(0≤x<2) [Formula 1].

### Claim 7 (depends on 1)

The method of claim 1, wherein the silicon-based active material has an average particle diameter (D50) of 5 μm to 35 μm.

### Claim 8 (depends on 1)

The method of claim 1, wherein a weight ratio of the carbon-based active material present in the first negative electrode active material layer to the silicon-based active material present in the second negative electrode active material layer is in a range of 45:65 to 95:5.

### Claim 9 (depends on 1)

The method of claim 1, wherein a ratio of a thickness of the second negative electrode active material layer to a thickness of the first negative electrode active material layer is in a range of 0.15 to 1.10.

### Claim 10 (depends on 1)

The method of claim 1, wherein the first negative electrode active material layer further comprises a first binder, and
the second negative electrode active material layer further comprises a second binder.

### Claim 11 (depends on 10)

The method of claim 10, wherein a weight ratio of the first binder present in the first negative electrode active material layer to the second binder present in the second negative electrode active material layer is in a range of 30:70 to 85:15.