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-2021184216-A1
Application number	US-201816761662-A
Country	US
Kind code	A1
Filing date	Nov 6, 2018
Priority date	Nov 6, 2017
Publication date	Jun 17, 2021
Grant date	—

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

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.

2 . The negative electrode active material of claim 1 ,
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.

3 . 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.

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

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

6 . 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 matrix doped with boron, wherein x of the SiC x matrix is 0.3 or more and less than 0.6.

7 . The method of claim 6 ,
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.

8 . The method of claim 6 ,
wherein the first heat treatment is performed at a temperature range of 1500° C. to 2500° C.

9 . The method of claim 6 ,
wherein the carrier gas is at least one selected from the group consisting of Ar, He, and Ne.

10 . The method of claim 6 ,
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.

11 . The method of claim 10 ,
wherein a temperature of the second heat treatment is in a range of 2000° C. to 2800° C.

12 . The method of claim 10 ,
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.

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

14 . The negative electrode of claim 13 further comprising,
a graphite-based active material.

15 . A secondary battery comprising:
the negative electrode of claim 13 ; a positive electrode: a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

Assignees

• Lg Chemical Ltd

Inventors

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

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• C01P2002/54

  one element only · CPC title

• C01P2006/40

  Electric properties · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title