CN-122025569-A - Negative electrode active material for lithium secondary battery and lithium secondary battery comprising same

Abstract

Disclosed is a negative electrode active material for a lithium secondary battery, and a lithium secondary battery comprising same. The anode active material for a lithium secondary battery according to an embodiment of the present disclosure includes composite particles including carbon-based particles including pores, and a silicon-containing coating layer disposed on the surface of the carbon-based particles, the ratio of the number of oxygen atoms to the number of silicon atoms (O/Si atomic number ratio) measured by X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, XPS) analysis at a depth of 100nm from the surface of the composite particles toward the center portion being 0.13 to 0.6. The negative electrode active material for a lithium secondary battery of the present disclosure has improved life characteristics.

Inventors

• Jin Leyuan
• Pu Guiyu
• Yu Daoai
• Cui Zaiying

Assignees

• SK新能源株式会社
• SK新技术株式会社

Dates

Publication Date

20260512

Application Date

20251107

Priority Date

20241111

Claims (15)

1. 1. A negative electrode active material for a lithium secondary battery, comprising composite particles, the composite particles comprising: carbon-based particles comprising pores, and A silicon-containing coating layer disposed on the surface of the carbon-based particles, The ratio of the number of oxygen atoms to the number of silicon atoms, i.e., the O/Si atomic number ratio, measured by X-ray photoelectron spectroscopy at a depth of 100nm from the surface toward the center of the composite particle is 0.13 to 0.6.
2. 2. The anode active material for a lithium secondary battery according to claim 1, wherein the O/Si atomic number ratio is 0.16 to 0.43.
3. 3. The anode active material for a lithium secondary battery according to claim 1, wherein the size of the pores of the carbon-based particles is 0.1nm to 10nm.
4. 4. The anode active material for a lithium secondary battery according to claim 3, wherein the size of the pores of the carbon-based particles is 1nm to 5nm.
5. 5. The anode active material for a lithium secondary battery according to claim 1, wherein the composite particles further comprise a carbon coating layer provided on the silicon-containing coating layer.
6. 6. The anode active material for a lithium secondary battery according to claim 5, wherein the carbon coating layer contains at least one selected from the group consisting of amorphous carbon and a conductive polymer.
7. 7. The anode active material for a lithium secondary battery according to claim 1, wherein the pores of the carbon-based particles include a shape recessed from an outermost peripheral portion of the carbon-based particles toward an inside of the carbon-based particles.
8. 8. 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.
9. 9. A method for preparing a negative active material for a lithium secondary battery, comprising: a step of preparing carbon-based particles containing pores, and A step of subjecting the carbon-based particles and the silicon-containing gas to three calcination at different temperatures to form composite particles comprising a silicon-containing coating layer formed on the surfaces of the carbon-based particles, The ratio of the number of oxygen atoms to the number of silicon atoms, i.e., the O/Si atomic number ratio, measured by X-ray photoelectron spectroscopy at a depth of 100nm from the surface toward the center of the composite particle is 0.13 to 0.6.
10. 10. The method for producing a negative electrode active material for a lithium secondary battery according to claim 9, wherein the silicon-containing gas comprises a silane gas.
11. 11. The method for producing a negative electrode active material for a lithium secondary battery according to claim 9, wherein the calcination includes a first calcination, a second calcination performed at a temperature higher than the first calcination, and a third calcination performed at a temperature higher than the second calcination.
12. 12. The method for producing a negative electrode active material for a lithium secondary battery according to claim 11, wherein the first calcination, the second calcination, and the third calcination are performed in this order.
13. 13. The method for producing a negative electrode active material for a lithium secondary battery according to claim 11, wherein the first calcination is performed at 400 ℃ to 450 ℃.
14. 14. The method for producing a negative electrode active material for a lithium secondary battery according to claim 11, wherein the second calcination is performed at 500 ℃ to 550 ℃.
15. 15. The method for producing a negative electrode active material for a lithium secondary battery according to claim 11, wherein the third calcination is performed at 600 ℃ to 650 ℃.

Description

Negative electrode active material for lithium secondary battery and lithium secondary battery comprising 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 rechargeable and dischargeable batteries, and with the development of information communication and display industries, they are widely used as power sources for portable electronic communication devices such as video cameras, cellular phones, notebook computers, and the like. In recent years, a battery pack including a secondary battery has been developed as a power source for an environment-friendly vehicle such as an electric vehicle. Examples of the secondary battery include lithium secondary batteries, nickel-cadmium batteries, and nickel-hydrogen batteries, which have been actively developed and used because of their high operating voltage and energy density per unit weight, and their favorable charge rate and light weight. Recently, as the application objects of lithium secondary batteries expand, lithium secondary batteries having higher capacity and power are being developed. For example, silicon and carbon having a relatively high capacity may be composited for the negative electrode active material. However, the silicon-carbon composite anode active material has a large difference in volume expansion ratio, and thus, with repeated charge and discharge, the anode active material may be cracked and exposed to the electrolyte. Disclosure of Invention Technical problem According to an aspect of the present disclosure, a negative electrode active material for a lithium secondary battery having improved life characteristics may be provided. According to another aspect of the present disclosure, a lithium secondary battery having improved life characteristics may be provided. According to another aspect of the present disclosure, a method of preparing a negative active material for a lithium secondary battery having improved life characteristics may be provided. Technical proposal Provided is a negative electrode active material for a lithium secondary battery, which comprises composite particles comprising carbon-based particles comprising pores, and a silicon-containing coating layer provided on the surface of the carbon-based particles, wherein the ratio of the number of oxygen atoms to the number of silicon atoms (O/Si atomic number ratio) measured by X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, XPS) analysis at a depth of 100nm from the surface of the composite particles toward the center is 0.13 to 0.6. In some embodiments, the O/Si atomic number ratio may be 0.16 to 0.43. In some embodiments, the size of the pores of the carbon-based particles may be 0.1nm to 10nm. In some embodiments, the size of the pores of the carbon-based particles may be 1nm to 5nm. In some embodiments, the composite particles may further comprise a carbon coating disposed on the silicon-containing coating. In some embodiments, the carbon coating may include at least one selected from the group consisting of amorphous carbon and conductive polymers. In some embodiments, the pores of the carbon-based particles may include a shape recessed from an outermost peripheral portion of the carbon-based particles toward an inside of the carbon-based particles. Provided is a lithium secondary battery comprising a negative electrode containing the negative electrode active material for a lithium secondary battery, and a positive electrode facing the negative electrode. A method for producing a negative electrode active material for a lithium secondary battery is provided, which comprises a step of preparing carbon-based particles containing pores, and a step of forming composite particles containing a silicon-containing coating layer formed on the surface of the carbon-based particles by three-time calcination of the carbon-based particles and a silicon-containing gas at different temperatures, wherein the ratio of the number of oxygen atoms to the number of silicon atoms (O/Si atomic number ratio) measured by X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy, XPS) analysis at a depth of 100nm from the surface of the composite particles toward the center is 0.13 to 0.6. In some embodiments, the silicon-containing gas may include a silane (silane) gas. In some embodiments, the calcining may include a first calcining, a second calcining performed at a temperature higher than the first calcining, and a third calcining performed at a temperature higher than the second calcining. In some embodiments, the first calcination, second calcination, and third calcination may be performed sequentially. In some embodiments, the first calcination may be performed at 400 ℃ to 450 ℃. In some embodiments, the second calcination may be performed at 500 ℃ to 550 ℃. In some embodimen