# US 11,909,035 B2 · Composite negative electrode material for lithium ion battery, preparation method thereof, and use thereof in lithium ion battery

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- Number: US 11,909,035 B2
- Document ID: US11909035B2
- Status: Granted
- Kind: B2
- Application number: 17/059,445
- Filed: 2019-02-18
- Published: 2021-05-27
- Granted: 2024-02-20
- Earliest claimed: 2018-05-31
- Assignees: Btr New Material Group Co., Ltd.
- Applicants: Btr New Material Group Co., Ltd.
- Inventors: Zhiqiang Deng; Chunlei Pang; Jianguo Ren; Youyuan Huang; Min Yue
- Web page: https://patentgrep.com/patent/US11909035B2

## CPC

- H01M 4/366: {as layered products}
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/483: {for non-aqueous cells (H01M4/485 takes precedence)}
- 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 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

The present application provides a composite negative electrode material of a lithium ion battery, a preparation method thereof and the use thereof in a lithium ion battery. The composite negative electrode material includes a SiOx-based active material and a polycarbonate coating layer coated on a surface of the SiOx-based active material. The method includes: (1) preparing a monomer solution of unsaturated carbonate; (2) polymerizing the monomer in presence of a polymerization catalyst to obtain a polymer solution; and (3) adding a SiOx-based active material, water and a polymer catalyst to the polymer solution, and further polymerizing to coat the SiOx-based active material, to obtain the composite negative electrode material.

## Claims

### Claim 1

A composite negative electrode material of a lithium ion battery, comprising a SiOx-based active material and a polycarbonate coating layer coated on a surface of the SiOx-based active material, wherein 0<x≤2, wherein the SiOx-based active material has a particle size ranging from larger than 20 μm to 100 μm or less, and wherein the SiOx-based active material and the polycarbonate coating layer are connected to each other by an unsaturated silane coupling agent.

### Claim 2 (depends on 1)

The composite negative electrode material according to claim 1, wherein the polycarbonate coating layer has a thickness ranging from 10 nm to 100 nm.

### Claim 3 (depends on 1)

The composite negative electrode material according to claim 1, wherein, based on 100% of a total mass of the SiOx-based active material, a mass percentage of the polycarbonate coating layer ranges from 0% to 10% excluding 0%.

### Claim 4 (depends on 1)

The composite negative electrode material according to claim 1, wherein the SiOx-based active material has a particle size ranging from 30 μm to 50 μm.

### Claim 5 (depends on 1)

The composite negative electrode material according to claim 1, wherein the polycarbonate coating layer is formed by polymerizing unsaturated carbonate, and the unsaturated carbonate has a structural formula of:
where at least one of R1 and R2 is an unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond, and if only one of R1 and R2 is the unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond, the other one of R1 and R2 is any one of H, alkyl, or an aromatic group.

### Claim 6 (depends on 1)

A preparation method of the composite negative electrode material according to claim 1, comprising:
step 1 of preparing a monomer solution of unsaturated carbonate;
step 2 of polymerizing the monomer in presence of a polymerization catalyst to obtain a polymer solution; and
step 3 of adding the SiOx-based active material, water and a polymer catalyst to the polymer solution, and further performing polymerizing to coat the SiOx-based active material, to obtain the composite negative electrode material.

### Claim 7 (depends on 6)

The method according to claim 6, further comprising a step of performing solid separation and drying, after the coating in the step 3 is completed.

### Claim 8 (depends on 6)

The method according to claim 6, wherein the step 1 comprises: dissolving the unsaturated carbonate and an unsaturated silane coupling agent in a solvent.

### Claim 9 (depends on 8)

The method according to claim 8, wherein in the step 1, the solvent is selected from the group consisting of water, methanol, ethanol, polypyrrolidone, isopropanol, tetrahydrofuran, ethyl acetate, N,N-dimethylacetamide, N,N-dimethylformamide, n-hexane, halogenated hydrocarbon, and combinations thereof, optionally selected from the group consisting of ethanol, polypyrrolidone, isopropanol, tetrahydrofuran, ethyl acetate, N,N-dimethylformamide, and combinations thereof.

### Claim 10 (depends on 6)

The method according to claim 6, wherein the method comprises the following steps:
dissolving the unsaturated carbonate and an unsaturated silane coupling agent in a solvent to prepare the monomer solution of the unsaturated carbonate;
polymerizing the monomer at 50° C. to 100° C. in the presence of the polymerization catalyst to obtain the polymer solution;
adding the SiOx-based active material, water and the polymer catalyst into the polymer solution, and further performing polymerizing at 50° C. to 100° C. to coat the SiOx-based active material; and
performing solid separation, and drying at 80° C. to 150° C. for 2 hours to 12 hours, to obtain the composite negative electrode material.

### Claim 11 (depends on 1)

A negative electrode, comprising the composite negative electrode material according to claim 1.

### Claim 12 (depends on 11)

A lithium ion battery, comprising the negative electrode according to claim 11.

### Claim 13 (depends on 1)

The composite negative electrode material according to claim 1, wherein the SiOx-based active material is selected from the group consisting of SiOx, SiOx/C, SiOx/M, and combinations thereof, where M is selected from the group consisting of alkali metal, alkaline earth metal, alkali metal oxide, alkaline earth metal oxide, and combinations thereof, and 0<x≤2.

### Claim 14 (depends on 1)

The composite negative electrode material according to claim 1, wherein the unsaturated silane coupling agent has a structural formula of:
where R3 is alkyl having 1 to 6 carbon atoms, and R4 is an unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond.

### Claim 15 (depends on 1)

The composite negative electrode material according to claim 1, wherein based on 100% of a total mass of the SiOx-based active material, a mass percentage of the unsaturated silane coupling agent ranges from 0% to 5%.

### Claim 16 (depends on 6)

The method according to claim 6, wherein in the step 1, a concentration of the unsaturated carbonate in the monomer solution ranges from 5 wt % to 10 wt %.

### Claim 17 (depends on 8)

The method according to claim 8, wherein in the step 1, a mass ratio of the unsaturated carbonate to the unsaturated silane coupling agent ranges from 2:1 to 7:1.

### Claim 18 (depends on 6)

The method according to claim 6, wherein the polymerization catalyst in the step 2 and the polymer catalyst in the step 3 are each independently selected from the group consisting of potassium persulfate, sodium persulfate, ammonium persulfate, dibenzoyl peroxide, and 2,2′-azobis(2-methylpropionitrile).

### Claim 19 (depends on 6)

The method according to claim 6, wherein a total polymerization time of the step 2 and the step 3 ranges from 2 hours to 10 hours; and the polymerizing in the step 2 and the polymerizing in the step 3 are each independently performed at a temperature of 50° C. to 100° C.