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CN-122000317-A - Negative electrode active material for lithium secondary battery, method for preparing the same, and lithium secondary battery including the same

CN122000317ACN 122000317 ACN122000317 ACN 122000317ACN-122000317-A

Abstract

The present disclosure provides a negative active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery including the same. The anode active material for a lithium secondary battery according to the present disclosure includes a silicon-based active material. The silicon-based active material includes silicon oxide particles and a carbon coating layer formed on at least a portion of the surface of the silicon oxide particles. The silicon-based active material has an O1s peak area ratio defined by a predetermined formula of 0.025 to 0.045. The negative electrode active material for a lithium secondary battery according to the present disclosure can ensure high output, high capacity characteristics. Furthermore, structural stability of the silicon oxide particles at high temperature can be improved upon repeated charge and discharge.

Inventors

  • PU LIANGKUI
  • JIN SHANE
  • LI ZHONGHE
  • Zheng Zhouhao
  • Cui Zaiying

Assignees

  • SK新能源株式会社
  • SK新技术株式会社

Dates

Publication Date
20260508
Application Date
20251031
Priority Date
20241104

Claims (20)

  1. 1. A negative electrode active material for a lithium secondary battery, comprising a silicon-based active material comprising silicon oxide particles and a carbon coating layer formed on at least a part of the surfaces of the silicon oxide particles, The O1s peak area ratio measured by X-ray photoelectron spectroscopy of the silicon-based active material and defined by the following formula 1 is 0.025 to 0.045, [ 1] O1s peak area ratio = a H /A O In formula 1, a H is an area of a si—oh peak measured by X-ray photoelectron spectroscopy of the silicon-based active material, and a O is an area of an O1s peak measured by X-ray photoelectron spectroscopy of the silicon-based active material.
  2. 2. The anode active material for a lithium secondary battery according to claim 1, wherein the O1s peak area ratio of the silicon-based active material is 0.026 to 0.04.
  3. 3. The negative electrode active material for a lithium secondary battery according to claim 1, wherein, The C1s peak area ratio measured by X-ray photoelectron spectroscopy of the silicon-based active material and defined by the following formula 2 is 0.2 to 1, [ 2] C1s peak area ratio=a L /A C In formula 2, a L is the area of the Li 2 CO 3 peak measured by X-ray photoelectron spectroscopy of the silicon-based active material, and a C is the area of the C1s peak measured by X-ray photoelectron spectroscopy of the silicon-based active material.
  4. 4. The anode active material for a lithium secondary battery according to claim 3, wherein the C1s peak area ratio of the silicon-based active material is 0.4 to 0.8.
  5. 5. The anode active material for a lithium secondary battery according to claim 1, wherein the silicon oxide particles include SiO x , 0< x≤2.
  6. 6. The negative electrode active material for a lithium secondary battery according to claim 1, wherein the surface arithmetic average roughness Ra measured by an atomic force microscope of the silicon-based active material is 0.2nm to 5nm.
  7. 7. The anode active material for a lithium secondary battery according to claim 6, wherein the surface arithmetic average roughness Ra of the silicon-based active material is 2nm to 4.5nm.
  8. 8. The negative electrode active material for a lithium secondary battery according to claim 6, wherein the surface arithmetic average roughness Ra is an arithmetic average of roughness values excluding a maximum value and a minimum value among surface roughness values measured in a scanning range of 0.5 μm x 0.5 μm for 10 to 20 regions of the surface of the silicon-based active material.
  9. 9. The anode active material for a lithium secondary battery according to claim 8, wherein a standard deviation of roughness values other than a maximum value and a minimum value among the measured surface roughness values is 1.5nm to 8nm.
  10. 10. The negative electrode active material for a lithium secondary battery according to claim 1, wherein, The peak intensity ratio of the raman spectrum defined by the following formula 3 is 0.5 to 5.5, [ 3] Peak intensity ratio of raman spectrum=i (520)/I (470) In formula 3, I (520) is the peak intensity of the silicon oxide particles in the region having a wavelength of 520cm -1 in the raman spectrum, and I (470) is the peak intensity of the silicon oxide particles in the region having a wavelength of 470cm -1 in the raman spectrum.
  11. 11. The negative electrode active material for a lithium secondary battery according to claim 1, wherein, The crystallite size of the silicon oxide particles measured by X-ray diffraction analysis and defined by the following formula 4 is 3nm to 5nm, [ 4] In formula 4, L is a crystallite size of the silicon oxide particles measured by X-ray diffraction analysis and expressed in units of nm, λ is an X-ray wavelength expressed in units of nm, β is a half-width of a peak of a (111) plane of the silicon oxide particles expressed in units of radian rad, and θ is a diffraction angle expressed in units of radian rad.
  12. 12. The anode active material for a lithium secondary battery according to claim 1, wherein the specific surface area of the silicon-based active material is 1m 2 /g to 4m 2 /g.
  13. 13. The anode active material for a lithium secondary battery according to claim 1, wherein the average particle diameter D50 of the silicon oxide particles is 4 μm to 6 μm.
  14. 14. The anode active material for a lithium secondary battery according to claim 1, further comprising a carbon-based active material.
  15. 15. The anode active material for a lithium secondary battery according to claim 14, wherein the carbon-based active material comprises artificial graphite, natural graphite, or a mixture thereof.
  16. 16. The negative electrode active material for a lithium secondary battery according to claim 1, wherein the content of the silicon-based active material is more than 0wt% and 10 wt% or less in the total weight of the negative electrode active material.
  17. 17. A lithium secondary battery comprising: A negative electrode comprising the negative electrode active material for a lithium secondary battery according to claim 1, and And a positive electrode facing the negative electrode.
  18. 18. A method for preparing a negative active material for a lithium secondary battery, comprising: A step of mixing a plurality of silicon sources and performing heat treatment to obtain silicon oxide particles, and A step of reacting the silicon oxide particles with a carbon source gas to form a carbon coating layer to obtain a silicon-based active material, The O1s peak area ratio measured by X-ray photoelectron spectroscopy of the silicon-based active material and defined by the following formula 1 is 0.025 to 0.045, [ 1] O1s peak area ratio = a H /A O In formula 1, a H is an area of a si—oh peak measured by X-ray photoelectron spectroscopy of the silicon-based active material, and a O is an area of an O1s peak measured by X-ray photoelectron spectroscopy of the silicon-based active material.
  19. 19. The method for producing a negative electrode active material for a lithium secondary battery according to claim 18, wherein the temperature of the heat treatment is 800 ℃ to 1200 ℃.
  20. 20. The method for producing a negative electrode active material for a lithium secondary battery according to claim 18, wherein the silicon source comprises silicon particles and silica (SiO 2 ) particles.

Description

Negative electrode active material for lithium secondary battery, method for preparing the same, and lithium secondary battery including the same Technical Field The present disclosure relates to a negative active material for a lithium secondary battery, a method of preparing the same, and a lithium secondary battery including the same. Background Secondary batteries are widely used as power sources for portable electronic communication devices such as video cameras, cellular phones, and notebook computers as the information communication and display industries develop as rechargeable and dischargeable batteries. In addition, in recent years, a battery pack including a secondary battery has been developed for use as a power source for an environment-friendly vehicle such as a hybrid vehicle. Examples of the secondary battery include lithium secondary batteries, nickel-cadmium batteries, and nickel-hydrogen batteries, and among them, lithium secondary batteries have been actively researched and developed because of their high operating voltage, high energy density per unit weight, high charging speed, and light weight. For example, a lithium secondary battery may include a positive electrode and a negative electrode. The positive electrode, the negative electrode and the like include electrode active materials capable of reversibly absorbing and releasing lithium ions. The current may be generated by a chemical reaction in the electrode. A graphite-based material or a silicon-based material may be used as the active material of the anode. Silicon-based active materials provide higher energy density, but undergo volumetric expansion or mechanical and chemical defects during charge and discharge, which may lead to a reduction in the lifetime of the secondary battery. Disclosure of Invention Technical problem An object of the present disclosure is to provide a negative electrode active material for a lithium secondary battery having improved output characteristics and life characteristics. An object of the present disclosure is to provide a method of preparing a negative active material for a lithium secondary battery having improved output characteristics and life characteristics. An object of the present disclosure is to provide a lithium secondary battery having improved output characteristics and life characteristics. Technical proposal The anode active material for a lithium secondary battery according to an embodiment of the present disclosure includes a silicon-based active material. The silicon-based active material includes silicon oxide particles and a carbon coating layer formed on at least a portion of the surface of the silicon oxide particles. The O1s peak area ratio measured by performing X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, XPS) analysis on the silicon-based active material and defined by the following formula 1 is 0.025 to 0.045. [ 1] O1s peak area ratio = a H/AO In formula 1, a H is the area of the si—oh peak measured by XPS on the silicon-based active material, and a O is the area of the O1s peak measured by XPS on the silicon-based active material. According to some embodiments, the O1s peak area ratio of the silicon-based active material may be 0.026 to 0.04. According to some embodiments, the C1s peak area ratio measured by performing X-ray photoelectron spectroscopy (XPS) analysis on the silicon-based active material and defined by the following formula 2 may be 0.2 to 1. [ 2] C1s peak area ratio=a L/AC In formula 2, a L is the area of the Li 2CO3 peak measured by XPS on the silicon-based active material, and a C is the area of the C1s peak measured by XPS on the silicon-based active material. According to some embodiments, the C1s peak area ratio of the silicon-based active material may be 0.4 to 0.8. According to some embodiments, the silicon oxide particles may include SiO x (0 < x≤2). According to some embodiments, the surface arithmetic average roughness (Ra) of the silicon-based active material measured using an atomic force microscope (atomic force microscope, AFM) may be 0.2nm to 5nm. According to some embodiments, the surface arithmetic average roughness (Ra) of the silicon-based active material may be 2nm to 4.5nm. According to some embodiments, the surface arithmetic average roughness (Ra) may be an arithmetic average of roughness values other than a maximum value and a minimum value among surface roughness values measured in a scanning range of 0.5 μm×0.5 μm for 10 to 20 regions of the surface of the silicon-based active material. According to some embodiments, the standard deviation of roughness values other than the maximum value and the minimum value among the measured surface roughness values may be 1.5nm to 8nm. According to some embodiments, the peak intensity ratio of the raman spectrum defined by the following formula 3 may be 0.5 to 5.5. [ 3] Peak intensity ratio of raman spectrum=i (520)/I (470) In formula 3, I (520) is the peak intens