Composite negative electrode material for lithium ion battery, preparation method thereof, and use thereof in lithium ion battery

Patent metadata

Field	Value
Publication number	US-11909035-B2
Application number	US-201917059445-A
Country	US
Kind code	B2
Filing date	Feb 18, 2019
Priority date	May 31, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

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.

First claim

What is claimed is:

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

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

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

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

5. 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 R 1 and R 2 is an unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond, and if only one of R 1 and R 2 is the unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond, the other one of R 1 and R 2 is any one of H, alkyl, or an aromatic group.

6. 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 SiO x -based active material, water and a polymer catalyst to the polymer solution, and further performing polymerizing to coat the SiO x -based active material, to obtain the composite negative electrode material.

7. 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.

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

9. 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.

10. 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 SiO x -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 SiO x -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.

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

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

13. The composite negative electrode material according to claim 1 , wherein the SiO x -based active material is selected from the group consisting of SiO x , SiO x /C, SiO x /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.

14. The composite negative electrode material according to claim 1 , wherein the unsaturated silane coupling agent has a structural formula of:

where R 3 is alkyl having 1 to 6 carbon atoms, and R 4 is an unsaturated group containing a carbon-carbon double bond or a carbon-carbon triple bond.

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

16. 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 %.

17. 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.

18. 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).

19. 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.

Assignees

• Btr New Mat Group Co Ltd

Inventors

• Deng Zhiqiang
• Pang Chunlei
• Ren Jianguo
• Huang Youyuan
• Yue Min

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title