# US 10,873,071 B2 · Silicon-based negative electrode active material and method for preparing the same

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- Number: US 10,873,071 B2
- Document ID: US10873071B2
- Status: Granted
- Kind: B2
- Application number: 15/521,532
- Filed: 2015-11-27
- Published: 2017-10-26
- Granted: 2020-12-22
- Earliest claimed: 2014-11-27
- Assignees: LG Chem, Ltd.
- Applicants: LG Chem, Ltd.
- Inventors: Hyun Chul Kim; Yong Ju Lee; Yoon Ah Kang; Eun Kyung Kim
- Web page: https://patentgrep.com/patent/US10873071B2

## CPC

- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- C08B 3/06: Cellulose acetate {, e.g. mono-acetate, di-acetate or tri-acetate}
- C08F 20/44: Acrylonitrile
- C08L 1/286: {substituted with acid radicals, e.g. carboxymethyl cellulose [CMC] (C08L1/282 takes precedence)}
- 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 4/621: {Binders}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A negative electrode active material of the present invention includes a core containing silicon-based nanoparticles and polymer carbides distributed on the nanoparticles, wherein the core has a size of 30-300 nm, and such a negative electrode active material is prepared using a method including dispersing a suspension in which silicon-based nanoparticles and water-soluble polymer are added to a solvent using ultrasonic waves; and preparing a core including the silicon-based nanoparticles having the polymer carbides on the surface by carbonizing the water-soluble polymer. As a result, a negative electrode active material having a significantly low volume expansion rate compared with general non-carbon-based negative electrode active materials, and having excellent electric conductivity may be provided.

## Claims

### Claim 1

A negative electrode active material comprising:
silicon-based nanoparticles; and
a carbonized water-soluble polymer on the silicon-based nanoparticle,
wherein the silicon-based nanoparticle having the carbonized water-soluble polymer thereon has a diameter in the range of 30 nm to 800 nm,
wherein the carbonized water-soluble polymer is included in 3% by weight to 20% by weight with respect to a total weight of the silicon-based nanoparticles,
wherein the silicon-based nanoparticles include any one material selected from the group consisting of SiO, SiM and a combination thereof, and M includes any one selected from the group consisting of Ni, Co, B, Cr, Cu, Fe, Mn, Ti, Y and a combination thereof,
wherein the carbonized water-soluble polymer is prepared by carbonizing a water-soluble polymer having a weight average molecular weight of 90,000 to 2,000,000,
wherein the water-soluble polymer is carboxymethylcellulose (CMC).

### Claim 2 (depends on 1)

The negative electrode active material of claim 1, wherein the silicon-based nanoparticles include an oxidized film on the surface.

### Claim 3 (depends on 1)

A method for preparing the negative electrode active material of claim 1 comprising:
dispersing a suspension in which the silicon-based nanoparticles and the water-soluble polymer are added to a solvent using ultrasonic waves; and
forming the carbonized water-soluble polymer on the surface of the silicon-based nanoparticles by carbonizing the water-soluble polymer.

### Claim 4 (depends on 3)

The method of claim 3, wherein the carbonization is carried out in a two-step process including a low-temperature carbonization process and a high-temperature carbonization process.

### Claim 5 (depends on 4)

The method of claim 4, wherein the low-temperature carbonization process is carried out using a spray drying apparatus, and includes injecting the suspension into a chamber inside a spray drying apparatus, and spray drying the suspension in the chamber.

### Claim 6 (depends on 5)

The method of claim 5, wherein the spray drying apparatus includes any one selected from the group consisting of an ultrasonic wave spray drying apparatus, an air nozzle spray drying apparatus, an ultrasonic wave nozzle spray drying apparatus, a filter expansion aerosol generator, an electrostatic spray drying apparatus and a combination thereof.

### Claim 7 (depends on 4)

The method of claim 4, wherein the low-temperature carbonization process is carried out at a temperature of 80° C. to 300° C.

### Claim 8 (depends on 4)

The method of claim 4, wherein the high-temperature carbonization process is heat treatment carried out at a temperature of 800° C. to 1100° C.

### Claim 9 (depends on 3)

The method of claim 3, wherein the solvent includes any one selected from the group consisting of water, acetone and a combination thereof.