Anode active material for lithium secondary battery, method of forming the same and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11862800-B2
Application number	US-202217692963-A
Country	US
Kind code	B2
Filing date	Mar 11, 2022
Priority date	Mar 11, 2021
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

An anode active material for a lithium secondary battery and a lithium secondary battery are provided. The anode active material includes a carbon-based particle including pores formed in at least one of an inside of the particle and a surface of the particle and having a pore size of the carbon-based particle is 20 nm or less, and silicon formed at an inside of the pores of the carbon-based particle or on the surface of the carbon-based particle. Silicon has an amorphous structure or a crystallite size of silicon measured by an XRD analysis is 7 nm or less. Difference between volume expansion ratios of carbon and silicon can be reduced to improve life-span property of the secondary battery.

First claim

What is claimed is:

1. An anode active material for a lithium secondary battery, comprising:
an amorphous carbon-based particle comprising pores formed in at least one of an inside of the particle and a surface of the particle, wherein a pore size of the carbon-based particle is 20 nm or less; and
silicon formed from a silicon-based compound gas at an inside of the pores of the carbon-based particle or on the surface of the carbon-based particle,
wherein the silicon has an amorphous structure or has a crystallite size measured by an X-ray diffraction (XRD) analysis which is 7 nm or less.

2. The anode active material for a lithium secondary battery of claim 1 , wherein the crystallite size of silicon is measured by Equation 1:

L
=

0
.
9

⁢
λ

β
⁢
cos
⁢
θ

[

Equation
⁢

1

]

wherein, in Equation 1, L is the crystallite size (nm), λ is an X-ray wavelength (nm), β is a full width at half maximum (rad) from a peak of a (111) plane of silicon, and θ is a diffraction angle (rad).

3. The anode active material for a lithium secondary battery of claim 1 , wherein the pore size of the carbon-based particle is less than 10 nm.

4. The anode active material for a lithium secondary battery of claim 1 , further comprising at least one of silicon oxide (SiOx, 0<x<2) and silicon carbide (SiC) formed at the inside of the pores of the carbon-based particle or on the surface of the carbon-based particle.

5. The anode active material for a lithium secondary battery of claim 4 , wherein a crystallite size of silicon included in silicon oxide is 7 nm or less.

6. The anode active material for a lithium secondary battery of claim 1 , wherein the silicon formed from the silicon-based compound gas is crystalline and has the crystallite size of 7 nm or less.

7. A lithium secondary battery, comprising:
an anode comprising an anode active material for a lithium secondary battery according to claim 1 ; and
a cathode facing the anode.

8. A method of forming an anode active material for a lithium secondary battery, comprising:
preparing an amorphous carbon-based particle including pores that have a pore size of 20 nm or less;
injecting a silicon-based compound gas to the carbon-based particle; and
firing the carbon-based particle together with the silicon-based compound gas to deposit silicon at an inside of the pores of the carbon-based particle or on the surface of the carbon-based particle,
wherein silicon has an amorphous structure or a crystallite size of silicon measured by an X-ray diffraction (XRD) analysis is 7 nm or less.

9. The method of claim 8 , wherein the firing is performed at a temperature less than 600° C.

10. The anode active material for a lithium secondary battery of claim 6 , wherein the crystallite size of the silicon formed from the silicon-based compound gas is 4 nm or less.

Assignees

• Sk On Co Ltd

Inventors

• Park Gwi Ok
• Yoo Seok Keun
• Chung Ju Ho

Classifications

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/1393

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

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title