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

Patent metadata

Field	Value
Publication number	US-2020388846-A1
Application number	US-201916769909-A
Country	US
Kind code	A1
Filing date	Mar 12, 2019
Priority date	Mar 14, 2018
Publication date	Dec 10, 2020
Grant date	—

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

1 . An amorphous silicon-carbon composite, comprising:
silicon and carbon mixed at a molecular level, wherein the amorphous silicon-carbon composite is in the form of particles having a diameter of 10 nm to 1 μm.

2 . The amorphous silicon-carbon composite of claim 1 , wherein the amorphous silicon-carbon composite comprises a silicon-carbon covalent bond, a silicon-silicon covalent bond, and a carbon-carbon covalent bond, 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.

3 . The amorphous silicon-carbon composite of claim 2 , wherein the amorphous silicon-carbon composite further comprises a heteroatom, and further comprises at least one bond selected from the group consisting of a heteroatom-carbon covalent bond and a heteroatom-silicon covalent bond.

4 . The amorphous silicon-carbon composite of claim 3 , wherein the heteroatom comprises at least one selected from the group consisting of boron, phosphorus, nitrogen, and sulfur.

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

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

7 . The amorphous silicon-carbon composite of claim 1 , wherein the amorphous silicon-carbon composite is formed by a pyrolysis deposition process for a silicon source and a carbon source.

8 . A method for preparing an amorphous silicon-carbon composite comprising the steps of:
a) mixing a silane compound comprising hydrocarbon with an organic solvent to prepare a mixed solution; and b) pyrolyzing the mixed solution in an inert atmosphere and depositing the result thereof on a substrate.

9 . The method of claim 8 , wherein the silane compound comprising hydrocarbon comprises at least one selected from the group consisting of tetramethylsilane, dimethylsilane, methylsilane, triethylsilane, phenylsilane, and diphenylsilane.

10 . The method of claim 8 , wherein in the step a), the silane compound comprising hydrocarbon further comprises a heteroatom.

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

12 . The method of claim 8 , 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.

13 . The method of claim 8 , wherein in the step b), a temperature of the pyrolysis is 600° C. to 900° C.

14 . The method of claim 8 , wherein in the step b), the pyrolysis is performed by a process of providing and bubbling an inert gas into the mixed solution.

15 . The method of claim 8 , further comprising a step of separating the deposited amorphous silicon-carbon composite from the substrate.

16 . The method of claim 15 , wherein the separated amorphous silicon-carbon composite is in the form of particles having a diameter of 10 nm to 1 μm.

17 . A negative electrode for a lithium secondary battery comprising an active material; a conductive material; and a binder, wherein the active material comprises the amorphous silicon-carbon composite of claim 1 .

18 . A lithium secondary battery comprising a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and an electrolyte solution, wherein the negative electrode is the negative electrode of claim 17 .

Assignees

• Lg Chemical 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

• H01M10/0525

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

• H01M4/364

  as mixtures · CPC title

• H01M4/1393

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