Anode active material for lithium secondary battery, method of preparing the same, and lithium secondary battery containing the same

Patent metadata

Field	Value
Publication number	US-2021151747-A1
Application number	US-202117158503-A
Country	US
Kind code	A1
Filing date	Jan 26, 2021
Priority date	Dec 7, 2017
Publication date	May 20, 2021
Grant date	—

Abstract

Provided are an anode active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery containing the same. The present invention provides an anode active material for a lithium secondary battery including: a carbon based particle; a first carbon coating layer positioned on the carbon based particle and including pores; a silicon coating layer positioned on the pores and/or a pore-free surface of the first carbon coating layer; and second carbon coating layer positioned on the silicon coating layer, a method of preparing the same, and a lithium secondary battery containing the same.

First claim

What is claimed is:

1 . An anode active material for a lithium secondary battery, the anode active material comprising:
a carbon/silicon composite comprising: a carbon based particle; a first carbon coating layer positioned on the carbon based particle and including pores; a silicon coating layer positioned on the first carbon coating layer; and wherein the anode active material further comprises a second carbon coating layer positioned on the carbon/silicon composite.

2 . The anode active material of claim 1 , wherein the silicon coating layer is positioned on the pores or a pore-free surface of the first carbon coating layer.

3 . The anode active material of claim 1 , wherein the first carbon coating layer includes the pores in an interior and a surface thereof.

4 . The anode active material of claim 1 , wherein an average pore size of the pores of the first carbon coating layer is 30 nm or more to 900 nm or less.

5 . The anode active material of claim 1 , wherein the anode active material satisfies the following Equation 1:
0.005≤ Da/Db≤ 0.02  [Equation 1]
in Equation 1, Da is an average pore size of the pores of the first carbon coating layer, and Db is an average particle size of the carbon based particle.

6 . The anode active material of claim 1 , wherein the carbon based particle is relatively nonporous compared to the first carbon coating layer and wherein a specific surface area when the first carbon coating layer is formed on the carbon based particle is increased by over 43% as compared to a specific surface area of only the carbon based particle due to the pores of the first carbon coating layer.

7 . The anode active material of claim 1 , wherein a thickness of the silicon coating layer is 10 nm or more to 100 nm or less.

8 . The anode active material of claim 1 , wherein the silicon coating layer is formed by a chemical vapor deposition (CVD) method.

9 . The anode active material of claim 1 , wherein the anode active material contains 30 wt % or more to 80 wt % or less of the carbon based particle, 5 wt % or more to 30 wt % or less of the first carbon coating layer, 5 wt % or more to 40 wt % or less of the silicon coating layer, and 5 wt % or more to 30 wt % or less of the second carbon coating layer based on a total weight of the anode active material.

10 . A method of preparing an anode active material for a lithium secondary battery, the method comprising:
(a) mixing and stirring carbon based particles, ceramic particles for forming a pore, and a first carbon precursor with each other; (b) forming a first carbon coating layer including pores on the carbon based particles by mixing a ceramic particle etching solution for forming a pore; (c) forming a silicon coating layer on the pores and/or a pore-free surface of the first carbon coating layer by a chemical vapor deposition (CVD) method; (d) mixing and stirring a second carbon precursor; and (e) performing sintering.

11 . The method of claim 10 , wherein in step (b), the pores are formed in the inside and a surface of the first carbon coating layer.

12 . The method of claim 10 , wherein an average particle size of the ceramic particles for forming a pore is 30 nm or more to 900 nm or less.

13 . The method of claim 10 , wherein the anode active material satisfies the following Equation 1:
0.005≤ Da/Db≤ 0.02  [Equation 1]
in Equation 1, Da is the average pore size of the pores of the first carbon coating layer, and Db is the average particle size of the carbon based particles.

14 . The method of claim 10 , wherein in step (c), the silicon coating layer is deposited with a thickness of 10 nm or more to 100 nm or less.

15 . The method of claim 10 , further comprising, between step (a) and step (b), (a-1) performing sintering.

16 . The method of claim 15 , wherein a sintering temperature in step (a-1) and/or step (e) is 600° C. or more to 1000° C. or less.

17 . The method of claim 10 , wherein at the time of stirring in step (a) and/or step (d), a solvent is sprayed.

18 . A lithium secondary battery comprising the anode active material of claim 1 .

Assignees

• Sk Innovation Co Ltd
• Ulsan Nat Inst Science & Tech Unist

Inventors

• Lee Jee Hee
• Kim Joon Sup
• Kim Nam Hyung
• Son Yeong Uk
• Lee Yoon Kwang
• Cho Jae Phil

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• C01B33/021

  Preparation (chemical coating from the vapour phase C23C16/00) · CPC title

• C23C16/24

  Deposition of silicon only · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/366 Primary

  as layered products · CPC title