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US-20260128288-A1 - ANODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, METHOD OF PREPARING THE SAME AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

US20260128288A1US 20260128288 A1US20260128288 A1US 20260128288A1US-20260128288-A1

Abstract

An anode active material for a lithium secondary battery includes a silicon-based active material that includes silicon oxide particles and a carbon coating layer formed on at least a portion of a surface of the silicon oxide particles. An O1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis is in a range from 0.025 and 0.045. A lithium secondary battery including the anode active material, and a method of preparing the anode active material are also provided.

Inventors

  • Yang Kyu PARK
  • Seon Ah KIM
  • Jong Hyuk Lee
  • Ju Ho Chung
  • Jae Young CHOI

Assignees

  • SK ON CO., LTD.
  • SK INNOVATION CO., LTD.

Dates

Publication Date
20260507
Application Date
20251030
Priority Date
20241104

Claims (20)

  1. 1 . An anode active material for a lithium secondary battery comprising a silicon-based active material that comprises silicon oxide particles and a carbon coating layer formed on at least a portion of a surface of the silicon oxide particles, wherein an O1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis and defined by Equation 1 is in a range from 0.025 and 0.045: O ⁢ 1 ⁢ s ⁢ peak ⁢ area ⁢ ratio = A H / A O [ Equation ⁢ 1 ] wherein, in Equation 1, A H is an area of a Si—OH peak measured by the XPS on the silicon-based active material, and A O is an area of an O1s peak measured by the XPS on the silicon-based active material.
  2. 2 . The anode active material for a lithium secondary battery of claim 1 , wherein the O1s peak area ratio of the silicon-based active material is in a range from 0.026 to 0.04.
  3. 3 . The anode active material for a lithium secondary battery of claim 1 , wherein a C1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis for the silicon-based active material and defined by Equation 2 is in a range from 0.2 to 1: C ⁢ 1 ⁢ s ⁢ peak ⁢ area ⁢ ratio = A L / A C [ Equation ⁢ 2 ] wherein, in Equation 2, A L is an area of a Li 2 CO 3 peak measured by the XPS on the silicon-based active material, and A C is an area of a C1s peak measured by the XPS on the silicon-based active material.
  4. 4 . The anode active material for a lithium secondary battery of claim 3 , wherein the C1s peak area ratio of the silicon-based active material is in a range from 0.4 to 0.8.
  5. 5 . The anode active material for a lithium secondary battery of claim 1 , wherein the silicon oxide particles comprise SiOx (0<x≤2).
  6. 6 . The anode active material for a lithium secondary battery of claim 1 , wherein an arithmetic average surface roughness (Ra) of the silicon-based active material which is measured using an atomic force microscope (AFM) is in a range from 0.2 nm and 5 nm.
  7. 7 . The anode active material for a lithium secondary battery of claim 6 , wherein the arithmetic average surface roughness (Ra) of the silicon-based active material is in a range from 2 nm and 4.5 nm.
  8. 8 . The anode active material for a lithium secondary battery of claim 6 , wherein the arithmetic average surface roughness (Ra) is an arithmetic mean of surface roughness values excluding maximum and minimum values measured over a scan range of 0.5 μm×0.5 μm for 10 to 20 areas on a surface of the silicon-based active material.
  9. 9 . The anode active material for a lithium secondary battery of claim 8 , wherein a standard deviation of the measured surface roughness values excluding the maximum and minimum values is in a range from 1.5 nm to 8 nm.
  10. 10 . The anode active material for a lithium secondary battery according to claim 1 , wherein a peak intensity ratio of a Raman spectrum defined by Equation 3 is in a range from 0.5 to 5.5: peak ⁢ intensity ⁢ ratio ⁢ of ⁢ Raman ⁢ spectrum = I ⁡ ( 5 ⁢ 2 ⁢ 0 ) / I ⁡ ( 4 ⁢ 7 ⁢ 0 ) [ Equation ⁢ 3 ] wherein, in Equation 3, I(520) is a peak intensity of the silicon oxide particles in the Raman spectrum at a wavelength of 520 cm −1 , and I(470) is a peak intensity of the silicon oxide particles in the Raman spectrum at a wavelength of 470 cm −1 .
  11. 11 . The anode active material for a lithium secondary battery of claim 1 , wherein a crystallite size of the silicon oxide particles as measured by an X-ray diffraction (XRD) analysis and defined by Equation 4 is in a range from 3 nm to 5 nm: L = 0.9 λ β ⁢ cos ⁢ θ [ Equation ⁢ 4 ] wherein, in Equation 4, L is the crystallite size of the silicon oxide particle measured by the XRD analysis and represented by a unit of nanometer (nm), λ is an X-ray wavelength represented by a unit of nanometer (nm), β is a full width at half maximum (FWHM) of a (111) plane of the silicon oxide particles represented by a unit of rad, and θ is a diffraction angle represented by a unit of rad.
  12. 12 . The anode active material for a lithium secondary battery of claim 1 , wherein a specific surface area of the silicon-based active material is in a range from 1 m 2 /g to 4 m 2 /g.
  13. 13 . The anode active material for a lithium secondary battery of claim 1 , wherein an average particle diameter (D50) of the silicon oxide particles is in a range from 4 μm to 6μ m.
  14. 14 . The anode active material for a lithium secondary battery of claim 1 , further comprising a carbon-based active material.
  15. 15 . The anode active material for a lithium secondary battery of claim 14 , wherein the carbon-based active material comprises artificial graphite, natural graphite, or a mixture thereof.
  16. 16 . The anode active material for a lithium secondary battery of claim 1 , wherein a content of the silicon-based active material is greater than 0 wt %, and 10 wt % or less, based on a total weight of the anode active material.
  17. 17 . A lithium secondary battery, comprising: an anode comprising the anode active material for a lithium secondary battery according to claim 1 ; and a cathode opposite to the anode.
  18. 18 . A method of preparing an anode active material for a lithium secondary battery, comprising: mixing and heat-treating silicon sources to obtain silicon oxide particles; and forming a carbon coating layer by reacting the silicon oxide particles with a carbon gas to obtain a silicon-based active material, wherein an O1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis and defined by Equation 1 is in a range from 0.025 and 0.045: O ⁢ 1 ⁢ s ⁢ peak ⁢ area ⁢ ratio = A H / A O [ Equation ⁢ 1 ] wherein, in Equation 1, A H is an area of a Si—OH peak measured by the XPS on the silicon-based active material, and A O is an area of an O1s peak measured by the XPS on the silicon-based active material.
  19. 19 . The method of claim 18 , wherein a temperature of the heat-treating is in a range from 800° C. to 1200° C.
  20. 20 . The method of claim 18 , wherein the silicon sources comprise silicon particles and silicon dioxide (SiO 2 ) particles.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Korean Patent Applications No. 10-2024-0154588 filed on Nov. 4, 2024 and No. 10-2025-0045736 filed on Apr. 8, 2025, in the Korean Intellectual Property Office (KIPO), the entire disclosure of which is incorporated by reference herein. BACKGROUND 1. Field The disclosure of this patent application relates to an anode active material for a lithium secondary battery, a method of preparing the same and a lithium secondary battery including the same. 2. Descriptions of the Related Art A secondary battery which can be charged and discharged repeatedly has been widely employed as a power source of a mobile electronic device such as a camcorder, a mobile phone, a laptop computer, etc., according to developments of information and display technologies. Recently, a battery pack including the secondary battery is being developed and applied as a power source of an eco-friendly vehicle such as an hybrid automobile. Examples of the secondary battery include a lithium secondary battery, a nickel-cadmium battery, a nickel-hydrogen battery, etc. The lithium secondary battery among the secondary batteries is being actively developed due to high operational voltage and energy density per unit weight, a high charging rate, a compact dimension, etc. For example, a lithium secondary battery may include a cathode and an anode. An electrode such as the cathode and the anode may include an electrode active material capable of reversibly absorbing and releasing lithium ions. A current may be generated through a chemical reaction in the electrode. A graphite-based material or a silicon-based material may be used as an active material for the anode. The silicon-based active material may provide high energy density. However, volume expansion, or mechanical and chemical defects may be caused during charging and discharging to reduce a life-span of the secondary battery. SUMMARY According to an aspect of the present disclosure, there is provided an anode active material for a lithium secondary battery having improved power and life-span properties. According to an aspect of the present disclosure, there is provided a method of preparing an anode active material for a lithium secondary battery having improved power and life-span properties. According to an aspect of the present disclosure, there is provided a lithium secondary battery having improved power and life-span properties. An anode active material for a lithium secondary battery includes a silicon-based active material that includes silicon oxide particles and a carbon coating layer formed on at least a portion of a surface of the silicon oxide particles. An O1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis and defined by Equation 1 is in a range from 0.025 and 0.045. O⁢1⁢s⁢ peak⁢ area⁢ ratio=AH/AO[Equation⁢ 1] In Equation 1, AH is an area of a Si—OH peak measured by the XPS on the silicon-based active material, and AO is an area of an O1s peak measured by the XPS on the silicon-based active material. In some embodiments, the O1s peak area ratio of the silicon-based active material may be in a range from 0.026 to 0.04. In some embodiments, a C1s peak area ratio measured by an X-ray photoelectron spectroscopy (XPS) analysis for the silicon-based active material and defined by Equation 2 is in a range from 0.2 to 1. C⁢1⁢s⁢ peak⁢ area⁢ ratio=AL/AC[Equation⁢ 2] In Equation 2, AL is an area of a Li2CO3 peak measured by the XPS on the silicon-based active material, and AC is an area of a C1s peak measured by the XPS on the silicon-based active material. In some embodiments, the C1s peak area ratio of the silicon-based active material may be in a range from 0.4 to 0.8. In some embodiments, the silicon oxide particles may include SiOx (0<x≤2). In some embodiments, an arithmetic average surface roughness (Ra) of the silicon-based active material which is measured using an atomic force microscope (AFM) may be in a range from 0.2 nm and 5 nm. In some embodiments, the arithmetic average surface roughness (Ra) of the silicon-based active material may be in a range from 2 nm and 4.5 nm. In some embodiments, the arithmetic average surface roughness (Ra) may be an arithmetic mean of surface roughness values excluding maximum and minimum values measured over a scan range of 0.5 μm×0.5 μm for 10 to 20 areas on a surface of the silicon-based active material. In some embodiments, a standard deviation of the measured surface roughness values excluding the maximum and minimum values may be in a range from 1.5 nm to 8 nm. In some embodiments, a peak intensity ratio of a Raman spectrum defined by Equation 3 may be in a range from 0.5 to 5.5. peak⁢ intensity⁢ ratio⁢ of⁢ Raman⁢ spectrum=I⁡(5⁢2⁢0)/I⁡(4⁢7⁢0)[Equation⁢ 3] In Equation 3, I(520) is a peak intensity of the silicon oxide particles in the Raman spectrum at a wavelength of 520 cm−1, and I(470) is a peak intensity