Negative electrode active material, negative electrode including the same, secondary battery including the negative electrode, and preparation method of the negative electrode active material

Patent metadata

Field	Value
Publication number	US-11495797-B2
Application number	US-201816761662-A
Country	US
Kind code	B2
Filing date	Nov 6, 2018
Priority date	Nov 6, 2017
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

A negative electrode active material including a silicon-carbon-based particle, the silicon-carbon-based particle having a SiCx matrix and boron doped in the SiCx matrix, wherein x of the SiCx matrix is 0.3 or more and less than 0.6.

First claim

The invention claimed is:

1. A negative electrode active material, comprising:
a silicon-carbon-based particle, wherein the silicon-carbon-based particle comprises:
a SiC x matrix; and
boron doped in the SiC x matrix,

wherein x of the SiC x matrix is 0.3 or more and less than 0.6, and
wherein the boron is present in an amount of 0.5 wt % to 1 wt % based on a total weight of the silicon-carbon-based particle.

2. The negative electrode active material of claim 1 ,
wherein an average particle diameter (D 50 ) of the silicon-carbon-based particles is 1 μm to 10 μm.

3. The negative electrode active material of claim 1 ,
wherein the SiC x matrix comprises SiC and Si.

4. The negative electrode active material of claim 1 ,
wherein the boron is present inside the SiC x matrix.

5. A negative electrode comprising the negative electrode active material of claim 1 .

6. The negative electrode of claim 5 further comprising,
a graphite-based active material.

7. A secondary battery comprising:
the negative electrode of claim 5 ;
a positive electrode:
a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

8. A method for preparing a negative electrode active material, the method comprising:
forming a matrix fluid by performing a first heat treatment wherein vaporized silicon source, carbon source, and carrier gas are introduced into a first reaction furnace; and
reacting the matrix fluid and boron in the gaseous state to form a SiC x matrix doped with boron, wherein
x of the SiC x matrix is 0.3 or more and less than 0.6, and
wherein the boron is present in an amount of 0.5 wt % to 1 wt % based on a total weight of the silicon-carbon-based particle.

9. The method of claim 8 ,
wherein in the step of forming of the matrix fluid,
a ratio of an inflow rate of the vaporized silicon source to an inflow rate of the carbon source is 1:0.3 to 1:0.6.

10. The method of claim 8 ,
wherein the first heat treatment is performed at a temperature range of 1500° C. to 2500° C.

11. The method of claim 8 ,
wherein the carrier gas is at least one selected from the group consisting of Ar, He, and Ne.

12. The method of claim 8 ,
wherein the step of forming of a SiC x matrix doped with boron comprises performing a second heat treatment by introducing the matrix fluid and the boron in the gaseous state into a second reaction furnace.

13. The method of claim 12 ,
wherein a temperature of the second heat treatment is in a range of 2000° C. to 2800° C.

14. The method of claim 12 ,
wherein a ratio of an inflow rate of the matrix fluid to an inflow rate of the boron in the gaseous state is 300:1 to 600:1.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Oh Il Geun
• Kim Eun Kyung
• Lee Yong Ju
• Jo Rae Hwan
• Lee Su Min
• Choi Jung Hyun

Classifications

• C04B2235/3826

  Silicon carbides · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• C04B35/565

  based on silicon carbide · CPC title

• C01B32/956

  Silicon carbide · CPC title

• C01P2006/40

  Electric properties · CPC title