Anode active material for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11967705-B2
Application number	US-202217856447-A
Country	US
Kind code	B2
Filing date	Jul 1, 2022
Priority date	Oct 8, 2021
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

An anode active material for a lithium secondary battery includes a carbon-based particle including pores therein, a silicon-containing coating layer formed at an inside the pores of the carbon-based particle or on a surface of the carbon-based particle, and a carbon coating layer formed on the silicon-containing coating layer. A full width at half maximum (FWHM) of an O1s peak of a surface measured by an X-ray photoelectron spectroscopy (XPS) is 2.0 or more. A lithium secondary battery including the anode active material having improved initial discharge capacity and capacity efficiency is provided.

First claim

What is claimed is:

1. An anode active material for a lithium secondary battery, comprising:
a carbon-based particle including pores therein;
a silicon-containing coating layer formed at an inside of the pores of the carbon-based particle or on a surface of the carbon-based particle; and
a carbon coating layer formed on the silicon-containing coating layer, and the carbon coating layer comprising a conductive polymer,
wherein the silicon-containing coating layer does not include silicon carbide (SiC),
wherein a full width at half maximum (FWHM) of an O1s peak of a surface of the anode active material measured by an X-ray photoelectron spectroscopy (XPS) is 2.0 or more,
wherein an XPS Si2p peak area ratio defined by Equation 3 is 15.0% or less:
XPS Si2 p peak area ratio (%)={ p 1/( p 1+ p 2+ p 3)}*100  [Equation 3]

wherein, in Equation 3, p1 is a peak area of a Si—O bond of SiO2 measured on the surface of the anode active material from the XPS, p2 is a peak area of a Si—O bond of SiO x (0<x<2) measured on the surface of the anode active material from the XPS, and p3 is a peak area of a Si—Si bond measured on the surface of the anode active material from the XPS.

2. The anode active material for a lithium secondary battery of claim 1 , wherein the carbon-based particle comprises at least one selected from the group consisting of activated carbon, a carbon nanotube, a carbon nanowire, graphene, a carbon fiber, carbon black, graphite, a porous carbon, a thermally decomposed cryogel, a thermally decomposed xerogel, and a thermally decomposed aerogel.

3. The anode active material for a lithium secondary battery of claim 1 , wherein the carbon-based particle has an amorphous structure.

4. The anode active material for a lithium secondary battery of claim 1 , wherein silicon included in the silicon-containing coating layer has an amorphous structure or a crystallite size measured through an X-ray diffraction (XRD) analysis of 7 nm or less.

5. The anode active material for a lithium secondary battery of claim 2 , wherein the crystallite size of silicon included in the silicon-containing coating layer is measured by Equation 1 below:
L= 0.9λ/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) of a (111) plane of silicon included in the silicon-containing coating layer, and θ is a diffraction angle (rad).

6. The anode active material for a lithium secondary battery of claim 1 , wherein silicon included in the silicon-containing coating layer has a peak intensity ratio of 1.2 or less in a Raman spectrum defined by Equation 2 below:
Peak intensity ratio of Raman spectrum= I (515)/ I (480)  [Equation 2]

wherein, in Equation 2, I(515) is a peak intensity of silicon included in the silicon-containing coating layer in a region having a wavenumber of 515 cm −1 in the Raman spectrum, and I(480) is a peak intensity of silicon included in the silicon-containing coating layer in a region having a wavenumber of 480 cm −1 in the Raman spectrum.

7. The anode active material for a lithium secondary battery of claim 1 , wherein the carbon coating layer is also formed on where the silicon-containing coating layer is not formed among the inside of the pores and the surface of the carbon-based particle.

8. The anode active material for a lithium secondary battery of claim 1 , wherein the FWHM of the O1s peak of the surface measured by the XPS is 2.4 or more.

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

Assignees

• Sk On Co Ltd
• Sk Innovation Co Ltd

Inventors

• Park Gwi Ok
• Yoo Seok Keun
• Jang Dong Il
• Chung Ju Ho

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/0471

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

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M10/0525

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