Amorphous silicon-carbon composite, preparation method therefor, and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-12159999-B2
Application number	US-202318110153-A
Country	US
Kind code	B2
Filing date	Feb 15, 2023
Priority date	Mar 14, 2018
Publication date	Dec 3, 2024
Grant date	Dec 3, 2024

Abstract

An amorphous silicon-carbon composite, a method for preparing the amorphous silicon-carbon composite using a pyrolysis method, a negative electrode for a lithium secondary battery, and a lithium secondary battery including the same.

First claim

The invention claimed is:

1. A method for preparing an amorphous silicon-carbon composite comprising the steps of:
a) mixing a silane compound containing hydrocarbon with an organic solvent to prepare a mixed solution; and
b) pyrolyzing the mixed solution in an inert atmosphere and depositing the amorphous silicon-carbon composite on a substrate; and
c) separating the deposited amorphous silicon-carbon composite from the substrate,
wherein the separated amorphous silicon-carbon composite comprises:
silicon and carbon mixed at a molecular level,
wherein the separated amorphous silicon-carbon composite comprises a silicon-carbon covalent bond, a silicon-silicon covalent bond, and a carbon-carbon covalent bond, and
wherein the silicon-carbon covalent bond, the silicon-silicon covalent bond, and the carbon-carbon covalent bond are irregularly present in the amorphous silicon-carbon composite.

2. The method of claim 1 , wherein the silane compound containing hydrocarbon comprises at least one selected from the group consisting of tetramethylsilane, dimethylsilane, methylsilane, triethylsilane, phenylsilane, and diphenylsilane.

3. The method of claim 1 , wherein in the step a), the silane compound containing hydrocarbon is a compound further containing a heteroatom.

4. The method of claim 3 , wherein the heteroatom is at least one selected from the group consisting of boron, phosphorus, nitrogen, and sulfur.

5. The method of claim 1 , wherein in the step a), the organic solvent comprises at least one selected from the group consisting of toluene, benzene, ethylbenzene, xylene, mesitylene, heptane, and octane.

6. The method of claim 1 , wherein in the step b), the pyrolysis temperature is 600 to 900° C.

7. The method of claim 1 , wherein in the step b), the pyrolysis is performed by a process of providing and bubbling an inert gas into the mixed solution.

8. The method of claim 1 , wherein the separated amorphous silicon-carbon composite has a diameter of 10 nm to 1 μm.

9. The method of claim 1 , wherein the separated amorphous silicon-carbon composite further comprises a heteroatom, and further comprises at least one bond of a heteroatom-carbon covalent bond and a heteroatom-silicon covalent bond.

10. The method of claim 9 , wherein the heteroatom is at least one selected from the group consisting of boron, phosphorus, nitrogen, and sulfur.

11. The method of claim 1 , wherein the separated amorphous silicon-carbon composite comprises silicon and carbon in a weight ratio of 3:7 to 7:3.

12. The method of claim 1 , wherein the separated amorphous silicon-carbon composite has a density of 0.2 to 0.6 g/cc.

Assignees

• Lg Energy Solution Ltd
• Ulsan Nat Inst Science & Tech Unist

Inventors

• Kim Jangbae
• Park Soojin
• Chae Jonghyun
• Yang Jihye
• Bok Taesoo
• Hong Dongki
• Ryu Jaegeon
• Yoo Seokkeun

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0525

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