Silicon-carbon negative electrode material, preparation method and application thereof

Abstract

The application relates to a silicon-carbon negative electrode material and a preparation method and application thereof, wherein the preparation method comprises the following steps: (1) mixing a silicon source, a carbon source and a binder with a solvent, and performing spray drying to obtain silicon-carbon composite particles; (2) mixing 1,3,5-tri(4-aminophenyl)benzene, p-benzene dicarboxaldehyde and trimesaldehyde after pre-polymerization, and mixing with the silicon-carbon composite particles obtained in the step (1), and performing reaction to obtain a precursor; (3) performing high-temperature carbonization treatment on the precursor to obtain the silicon-carbon negative electrode material. The silicon-carbon negative electrode material prepared by the method has good conductivity, good rate performance, and constant particle volume in the cycle process, so that the falling-off of the electrode sheet powder in the cycle process can be avoided to a great extent, and the cycle performance is stable.

Description

Technical Field

[0001] This application relates to the field of battery materials technology, such as a silicon-carbon anode material, its preparation method, and its application. Background Technology

[0002] Silicon, as the anode material for lithium-ion batteries, boasts a theoretical specific capacity of up to 4000 mAh / g, making it the lithium-ion battery anode material with the highest known specific capacity, thus attracting widespread attention from researchers. However, due to its significant volume expansion effect, silicon electrode materials are prone to pulverization after expansion, causing them to detach from the anode current collector and resulting in the loss of electrical connection between the anode active material and the current collector. Extensive research has been conducted to address this defect in silicon materials and to solve the aforementioned problems.

[0003] The most common approach is to combine silicon and carbon materials to prepare silicon-carbon anode materials, using carbon coating to suppress the volume expansion of silicon and improve its conductivity. However, this approach is not effective in improving the cycle performance and rate performance of the material.

[0004] In addition, CN109216693A discloses a method for preparing silicon-carbon anode materials for lithium-ion batteries. It utilizes in-situ growth of nano-Si and CNTs on MOF-5 and high-temperature carbonization to obtain silicon-carbon composite materials. Since the nano-Si is uniformly coated by the carbonization layer, the expansion of Si can be suppressed. Furthermore, the addition of CNTs to the anode material can act as a conductive network structure, greatly improving the electronic conductivity of the silicon-carbon anode, thereby improving the first efficiency and rate performance of the silicon-carbon anode during charge-discharge cycles.

[0005] Although the above methods can suppress the expansion of silicon-based anode materials to a certain extent and improve their electrochemical performance, MOF materials generally have poor stability. Long-term high-temperature treatment will cause their structure to collapse, which will damage the protective layer that suppresses the expansion of nano-silicon and affect the electrochemical performance of the material. Summary of the Invention

[0006] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0007] This application provides a silicon-carbon anode material, its preparation method, and its application. The silicon-carbon anode material prepared by the method described in this application has good conductivity, good rate performance, and unchanged particle volume during cycling. Therefore, it can largely prevent the anode material from falling off the electrode during cycling and improve the stability of the material's cycling performance.

[0008] In a first aspect, this application provides a method for preparing a silicon-carbon anode material, the method comprising the following steps:

[0009] (1) Mix silicon source, carbon source and binder with solvent and spray dry to obtain silicon-carbon composite particles;

[0010] (2) After prepolymerizing 1,3,5-tris(4-aminophenyl)benzene (TAPB), terephthalaldehyde (PDA) and pyromellitic trimethylolpropane (BTCA), they are mixed with the silicon-carbon composite particles obtained in step (1) and reacted to obtain the precursor.

[0011] (3) The precursor is subjected to high-temperature carbonization treatment to obtain the silicon-carbon anode material.

[0012] This application uses 1,3,5-tris(4-aminophenyl)benzene (TAPB), terephthalaldehyde (PDA), and trimesophthalaldehyde (BTCA) as raw materials to polymerize a COF cage. The COF cage exhibits high thermal stability, allowing it to exist stably in the lithium-ion electrolyte environment. Furthermore, the porous structure of the generated COF provides a large surface area, facilitating the diffusion of electrolyte and lithium ions into the silicon-carbon core, thus improving the material's initial efficiency and rate performance. The COF cage effectively confines elemental silicon within its "cage," providing sufficient buffer space against the volume effect of elemental silicon. The overall volume of the resulting Si / C@COF anode material remains essentially unchanged during charge and discharge, thus fully utilizing the specific capacity of the silicon anode while ensuring the material's cycle stability.

[0013] In one embodiment, the silicon source in step (1) comprises nano-silicon particles.

[0014] In one embodiment, the median particle size D50 of the silicon source is 100–500 nm, for example: 100 nm, 200 nm, 300 nm, 400 nm, or 500 nm.

[0015] In one embodiment, the carbon source includes any one or a combination of at least two of organic carbon sources, carbon nanotubes, carbon nanofibers, or graphene.

[0016] In one embodiment, the adhesive comprises any one or a combination of at least two of melamine-formaldehyde resin, carboxymethyl cellulose, polyethylene oxide, or polyvinyl alcohol.

[0017] In one embodiment, the solvent includes any one or a combination of at least two of water, methanol, or ethanol.

[0018] In one embodiment, the mass ratio of silicon source, carbon source and binder in step (1) is 50:(4~6):(0.8~1.5), for example: 50:4:0.8, 50:5:1, 50:4:0.9, 50:6:0.8 or 50:6:1.5, etc.

[0019] In one embodiment, the spray drying temperature is 100-200°C, for example: 100°C, 120°C, 150°C, 180°C, or 200°C.

[0020] In one embodiment, the median particle size D50 of the silicon-carbon composite particles is 0.5 to 1.5 μm, for example: 0.5 μm, 0.8 μm, 1 μm, 1.2 μm or 1.5 μm, etc.

[0021] In one embodiment, the prepolymerization in step (2) comprises stirring 1,3,5-tris(4-aminophenyl)benzene, terephthalaldehyde and pyromellitic methylbenzene in a mixed solution of aniline and benzaldehyde.

[0022] In one embodiment, the stirring time is 3 to 5 minutes, for example: 3 minutes, 3.5 minutes, 4 minutes, 4.5 minutes or 5 minutes, etc.

[0023] In one embodiment, during the prepolymerization process, the concentration of the amino group of 1,3,5-tris(4-aminophenyl)benzene in the system is 20-40 mmol / L.

[0024] In one embodiment, during the prepolymerization process, the total concentration of aldehyde groups in terephthalaldehyde and trimesin in the system is 20–40 mmol / L.

[0025] In one embodiment, during the prepolymerization process, the total concentration of amino groups in aniline and aldehyde groups in benzaldehyde in the system is 100–150 mmol / L.

[0026] In one embodiment, the molar ratio of terephthalaldehyde and trimesophthalaldehyde is (1-3):2, for example: 1:2, 1.5:2, 2:2, 2.5:2 or 3:2, etc.

[0027] In one embodiment, the solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactant in step (2) is 0.01 to 0.05 g / mL, for example: 0.01 g / mL, 0.02 g / mL, 0.03 g / mL, 0.04 g / mL or 0.05 g / mL, etc.

[0028] In one embodiment, stirring is performed during the mixing process.

[0029] In one embodiment, the stirring speed is 100 to 1500 rpm, for example: 100 rpm, 500 rpm, 1000 rpm, 1200 rpm or 1500 rpm.

[0030] In one embodiment, the reaction temperature in step (2) is 20 to 40°C, for example: 20°C, 25°C, 30°C, 35°C or 40°C.

[0031] In one embodiment, the reaction time is 30 to 80 hours, for example: 30 hours, 40 hours, 50 hours, 60 hours, or 80 hours.

[0032] In one embodiment, the precursor includes a coating layer.

[0033] In one embodiment, the thickness of the coating layer is 10 to 100 nm, for example: 10 nm, 20 nm, 50 nm, 80 nm or 100 nm.

[0034] In one embodiment, the temperature of the high-temperature carbonization treatment in step (3) is 650 to 800°C, for example: 650°C, 680°C, 700°C, 750°C or 800°C, etc.

[0035] In one embodiment, the high-temperature carbonization treatment time is 0.5 to 1 hour, for example: 0.5 hours, 0.6 hours, 0.8 hours, 0.9 hours, or 1 hour.

[0036] This application achieves improved conductivity of the anode material through simple high-temperature carbonization of a portion of the COF cage. Furthermore, the COF material exhibits good thermal stability, and its structure does not collapse even after short-term heat treatment. In addition, the synthesized COF material has abundant amino groups on its surface, which increases the electron density and improves conductivity. Moreover, it provides certain lithium intercalation sites, thereby enhancing the discharge capacity.

[0037] Secondly, this application provides a silicon-carbon anode material, which is prepared by the method described in the first aspect.

[0038] Thirdly, this application provides a negative electrode sheet comprising the silicon-carbon negative electrode material as described in the second aspect.

[0039] Fourthly, this application provides a lithium-ion battery comprising a negative electrode as described in the third aspect.

[0040] Compared with related technologies, this application has the following advantages:

[0041] (1) This application uses specific raw materials to make a COF cage with high thermal stability. The porous structure of COF provides a large surface area, which is conducive to the diffusion of electrolyte and lithium ions to the silicon carbon core, improving the first efficiency and rate performance of the material. The COF cage can place elemental silicon in a "cage" and provide sufficient buffer space to adapt to the volume effect of elemental silicon. Short-term high-temperature carbonization can avoid structural collapse while further improving the conductivity of the material.

[0042] (2) The battery made of the silicon-carbon anode material described in this application has a 0.1C discharge capacity of more than 2324.65 mAh / g, a 100-cycle capacity retention rate of more than 97.98%, and a 2C / 0.1C capacity retention rate of more than 53.87%.

[0043] After reading and understanding the accompanying diagrams and detailed descriptions, the other aspects can be understood. Attached Figure Description

[0044] The accompanying drawings are used to provide a further understanding of the technical solutions in this paper and form part of the specification. They are used together with the embodiments of this application to explain the technical solutions in this paper and do not constitute a limitation on the technical solutions in this paper.

[0045] Figure 1 This is a schematic diagram illustrating the synthesis of the silicon-carbon anode material according to an embodiment of this application. Detailed Implementation

[0046] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0047] Example 1

[0048] This embodiment provides a silicon-carbon anode material, and a schematic diagram of the synthesis of the silicon-carbon material is shown below. Figure 1 As shown, the preparation method of the silicon-carbon anode material is as follows:

[0049] (1) Nano-silicon particles with a D50 of 200 nm are uniformly dispersed in water with carboxymethyl cellulose and carbon nanotubes at a mass ratio of 50:1:5 to form a slurry, and spray-dried at 150°C to obtain spherical and / or near-spherical silicon-carbon composite particles with a D50 of 0.8 μm.

[0050] (2) TAPB (1,3,5-tris(4-aminophenyl)benzene), PDA (terephthalaldehyde), and BTCA (trimethylbenzene) were mixed and stirred in a mixed solution of aniline and benzaldehyde for 3 min for prepolymerization. The concentration of amino groups in TAPB and the concentration of aldehyde groups in BTCA and PDA in the mixture were maintained at 30 mmol / L. The concentration of amino groups and aldehyde groups in the mixed solution of aniline and benzaldehyde was 120 mmol / L. The molar ratio of PDA to BTCA was 3:2. Then, the silicon-carbon composite particles obtained in step (1) were added to the above mixed solution. The solid-liquid ratio of silicon-carbon composite particles to reactants was 0.03 g / mL. The reaction was stirred at 300 rpm and reacted at 25°C for 60 h, so that the surface reactants and the silicon-carbon anode core present a core-cage structure with a coating thickness of 50 nm. Then, the reaction solution was filtered, washed, and dried to obtain the precursor.

[0051] (3) The precursor is reacted at 750°C for 40 min to carbonize part of the COF cage at a short-term high temperature to obtain the silicon-carbon anode material.

[0052] Example 2

[0053] This embodiment provides a silicon-carbon anode material, and a schematic diagram of the synthesis of the silicon-carbon material is shown below. Figure 1 As shown, the preparation method of the silicon-carbon anode material is as follows:

[0054] (1) Nano-silicon particles with a D50 of 500 nm are uniformly dispersed in water with carboxymethyl cellulose and carbon nanotubes at a mass ratio of 50:1.5:6 to form a slurry, and spray-dried at 150°C to obtain spherical and / or near-spherical silicon-carbon composite particles with a D50 of 1.5 μm.

[0055] (2) TAPB (1,3,5-tris(4-aminophenyl)benzene), PDA (terephthalaldehyde), and BTCA (trimethylbenzene) were mixed and stirred in a mixed solution of aniline and benzaldehyde for 4 min for prepolymerization. The concentration of amino groups in TAPB and the concentration of aldehyde groups in BTCA and PDA in the mixture were maintained at 20 mmol / L. The concentration of amino groups and aldehyde groups in the mixed solution of aniline and benzaldehyde was 100 mmol / L. The molar ratio of PDA to BTCA was 1:2. Then, the silicon-carbon composite particles obtained in step (1) were added to the above mixed solution. The solid-liquid ratio of silicon-carbon composite particles to reactants was 0.05 g / mL. The reaction was stirred at 1000 rpm and reacted at 25°C for 30 h, so that the surface reactants and the silicon-carbon anode core formed a core-cage structure with a coating thickness of 80 nm. Then, the reaction solution was filtered, washed, and dried to obtain the precursor.

[0056] (3) The precursor is reacted at 650°C for 60 min to carbonize part of the COF cage in a short-time high temperature to obtain the silicon-carbon anode material.

[0057] Example 3

[0058] This embodiment provides a silicon-carbon anode material, and a schematic diagram of the synthesis of the silicon-carbon material is shown below. Figure 1 As shown, the preparation method of the silicon-carbon anode material is as follows:

[0059] (1) Nano-silicon particles with a D50 of 100 nm are uniformly dispersed in water with carboxymethyl cellulose and carbon nanotubes at a mass ratio of 50:0.8:4 to form a slurry, and spray-dried at 100 °C to obtain spherical and / or near-spherical silicon-carbon composite particles with a D50 of 0.5 μm.

[0060] (2) TAPB (1,3,5-tris(4-aminophenyl)benzene), PDA (terephthalaldehyde), and BTCA (trimethylbenzene) were mixed and stirred in a mixed solution of aniline and benzaldehyde for 5 min for prepolymerization. The concentration of amino groups in TAPB and the concentration of aldehyde groups in BTCA and PDA in the mixture were maintained at 40 mmol / L. The concentration of amino groups and aldehyde groups in the mixed solution of aniline and benzaldehyde was 150 mmol / L. The molar ratio of PDA to BTCA was 2:2. Then, the silicon-carbon composite particles obtained in step (1) were added to the above mixed solution. The solid-liquid ratio of silicon-carbon composite particles to reactants was 0.01 g / mL. The reaction was stirred at 100 rpm and reacted at 25°C for 80 h. This resulted in a core-cage structure between the surface reactants and the silicon-carbon anode core. The coating thickness was 20 nm. The reaction solution was then filtered, washed, and dried to obtain the precursor.

[0061] (3) The precursor is reacted at 800°C for 30 min to carbonize part of the COF cage at a short-term high temperature to obtain the silicon-carbon anode material.

[0062] Example 4

[0063] The only difference between this embodiment and Example 1 is that the solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactant is 0.005 g / L. All other conditions and parameters are exactly the same as in Example 1.

[0064] Example 5

[0065] The only difference between this embodiment and Example 1 is that the solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactant is 0.1 g / L. All other conditions and parameters are exactly the same as in Example 1.

[0066] Example 6

[0067] The only difference between this embodiment and Example 1 is that the molar ratio of terephthalaldehyde and pyromellitic methylaldehyde is 3:1. All other conditions and parameters are exactly the same as in Example 1.

[0068] Example 7

[0069] The only difference between this embodiment and Example 1 is that the molar ratio of terephthalaldehyde and pyromellitic methylaldehyde is 1:3. All other conditions and parameters are exactly the same as in Example 1.

[0070] Example 8

[0071] The only difference between this embodiment and embodiment 1 is that the reaction time in step (2) is 10 hours, while the other conditions and parameters are exactly the same as in embodiment 1.

[0072] Example 9

[0073] The only difference between this embodiment and embodiment 1 is that the high-temperature carbonization treatment time in step (3) is 2 hours, while the other conditions and parameters are exactly the same as in embodiment 1.

[0074] Comparative Example 1

[0075] This comparative example directly uses step (1) to obtain silicon-carbon composite particles, without performing steps (2) and (3).

[0076] Comparative Example 2

[0077] The only difference between this comparative example and Example 1 is that step (3) high-temperature carbonization treatment is not performed; all other conditions and parameters are exactly the same as in Example 1.

[0078] Performance testing:

[0079] The silicon-carbon anode material prepared in the above examples and comparative examples was uniformly mixed with acetylene black and polyacrylic acid at a mass ratio of 80:10:10 and ground for 30 minutes. The mixture was then uniformly coated onto copper foil, vacuum dried at 90°C, and rolled to obtain the anode sheet. A coin cell was prepared using a lithium metal sheet as the counter electrode, a polypropylene membrane as the separator, and 1M lithium hexafluorophosphate as the electrolyte.

[0080] The test conditions were: a test temperature of 25℃, and 0.1C charge / discharge cycle performance and 2C rate performance tests conducted within a voltage range of 0.05V-2V. The test results are shown in Table 1.

[0081] Table 1

[0082]

[0083]

[0084] As can be seen from Table 1, as obtained from Examples 1-3, the 0.1C discharge capacity of the battery made of the silicon-carbon anode material described in this application can reach more than 2324.65 mAh / g, the capacity retention rate after 100 cycles can reach more than 97.98%, and the capacity retention rate at 2C / 0.1C can reach more than 53.87%.

[0085] A comparison of Examples 1 and 4-5 shows that during the preparation of the silicon-carbon anode material described in this application, the solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactants affects its performance. Controlling the solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactants to 0.01-0.05 g / mL results in a silicon-carbon anode material with better performance. If the solid-liquid ratio is too large, the COF outer layer formed will be too thin, resulting in lower material strength. If the solid-liquid ratio is too small, the COF outer layer formed by the reaction will be too thick, affecting the material capacity.

[0086] A comparison of Examples 1 and 6-7 shows that the molar ratio of terephthalaldehyde and trimesophthalaldehyde affects the performance of the silicon-carbon anode material described in this application. Controlling the molar ratio of terephthalaldehyde and trimesophthalaldehyde to (1-3):2 results in a silicon-carbon anode material with better performance. If the proportion of terephthalaldehyde is too large, a hollow core-cage structure cannot be formed, and sufficient volume expansion space cannot be provided for the silicon-carbon anode, affecting the stability of the material. If the proportion of terephthalaldehyde is too small, the formed cage layer is too thin, with too many pores and low strength, making it easy to break during the reaction.

[0087] Comparing Example 1 and Example 8, it can be seen that the reaction time in step (2) affects the performance of the silicon-carbon anode material. If the reaction time is too short, a cage-like structure cannot be generated, and it is only a general coating layer, which cannot provide enough space for the silicon-carbon anode to expand in volume, thus affecting the stability of the material.

[0088] Comparing Example 1 and Example 9, it can be seen that the high-temperature carbonization time in step (3) will affect the performance of the silicon-carbon anode material. If the high-temperature carbonization time is too long, the cage layer formed will be too thin, with too many pores and low strength, and it will be easy to break during the reaction.

[0089] Comparing Example 1 and Comparative Example 1, it can be seen that this application uses 1,3,5-tris(4-aminophenyl)benzene (TAPB), terephthalaldehyde (PDA), and trimesophthalaldehyde (BTCA) as raw materials to polymerize a COF cage. The COF cage exhibits high thermal stability, allowing it to exist stably in the lithium-ion electrolyte environment. Furthermore, the porous structure of the generated COF provides a large surface area, which is beneficial for the diffusion of electrolyte and lithium ions into the silicon-carbon core, thus improving the material's initial efficiency and rate performance. The COF cage can place elemental silicon within a "cage," providing sufficient buffer space to accommodate the volume effect of elemental silicon. The overall volume of the resulting Si / C@COF anode material remains essentially unchanged during charge and discharge, thus fully utilizing the specific capacity of the silicon anode while ensuring the material's cycle stability.

[0090] As can be seen from the comparison between Example 1 and Comparative Example 2, this application can further improve the conductivity of the negative electrode material by simply carbonizing a portion of the COF cage at high temperature. Furthermore, the COF material exhibits good thermal stability, and its structure does not collapse even after short-term heat treatment. In addition, the synthesized COF material has abundant amino groups on its surface, which can increase the electron density and improve the conductivity. Moreover, it can also provide certain lithium intercalation sites, thereby increasing the discharge capacity.

[0091] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A method for preparing a silicon-carbon anode material, comprising the following steps: (1) Mix silicon source, carbon source and binder with solvent and spray dry to obtain silicon-carbon composite particles; (2) After prepolymerizing 1,3,5-tris(4-aminophenyl)benzene, terephthalaldehyde and pyromellitic methyl ester, they are mixed with the silicon-carbon composite particles obtained in step (1) and reacted to obtain the precursor. (3) The precursor is subjected to high-temperature carbonization treatment to obtain the silicon-carbon anode material; The molar ratio of terephthalaldehyde and pyromellitic aldehyde is (1-3):2; The solid-liquid ratio of the silicon-carbon composite particles and the prepolymerized reactants in step (2) is 0.01 to 0.05 g / mL.

2. The preparation method according to claim 1, wherein, The silicon source in step (1) includes nano-silicon particles.

3. The preparation method according to claim 1, wherein, The median particle size D50 of the silicon source is 100–500 nm.

4. The preparation method according to claim 1, wherein, The carbon source includes any one or a combination of at least two of the following: organic carbon source, carbon nanotubes, carbon nanofibers, or graphene.

5. The preparation method according to claim 1, wherein, The adhesive includes any one or a combination of at least two of melamine-formaldehyde resin, carboxymethyl cellulose, polyethylene oxide, or polyvinyl alcohol.

6. The preparation method according to claim 1, wherein, The solvent includes any one of water, methanol, or ethanol, or a combination of at least two of them.

7. The preparation method according to claim 1, wherein, The mass ratio of silicon source, carbon source and binder in step (1) is 50:(4~6):(0.8~1.5).

8. The preparation method according to claim 1, wherein the spray drying temperature is 100-200°C.

9. The preparation method according to claim 1, wherein, The median particle size D50 of the silicon-carbon composite particles is 0.5–1.5 μm.

10. The preparation method according to claim 1, wherein, The prepolymerization in step (2) involves stirring 1,3,5-tris(4-aminophenyl)benzene, terephthalaldehyde, and pyromellitic methyl benzoate in a mixed solution of aniline and benzaldehyde.

11. The preparation method according to claim 10, wherein, The stirring time is 3 to 5 minutes.

12. The preparation method according to claim 10, wherein, During the prepolymerization process, the concentration of the amino group of 1,3,5-tris(4-aminophenyl)benzene in the system is 20-40 mmol / L.

13. The preparation method according to claim 10, wherein, During the prepolymerization process, the total concentration of aldehyde groups in terephthalaldehyde and trimesin in the system is 20–40 mmol / L.

14. The preparation method according to claim 10, wherein, During the prepolymerization process, the total concentration of amino groups in aniline and aldehyde groups in benzaldehyde in the system is 100–150 mmol / L.

15. The preparation method according to claim 1, wherein, Stirring is performed during the mixing process.

16. The preparation method according to claim 15, wherein, The stirring speed is 100-1500 rpm.

17. The preparation method according to claim 1, wherein, The reaction temperature in step (2) is 20–40 °C.

18. The preparation method according to claim 1, wherein, The reaction time in step (2) is 30 to 80 hours.

19. The preparation method according to claim 1, wherein, The precursor includes a coating layer.

20. The preparation method according to claim 19, wherein, The thickness of the coating layer is 10–100 nm.

21. The preparation method according to claim 1, wherein, The high-temperature carbonization process in step (3) is carried out at a temperature of 650–800°C.

22. The preparation method according to claim 1, wherein, The high-temperature carbonization treatment in step (3) takes 0.5 to 1 hour.

23. A silicon-carbon anode material, wherein, The silicon-carbon anode material is prepared by the method described in any one of claims 1-22.

24. A negative electrode plate, wherein, The negative electrode comprises the silicon-carbon negative electrode material as described in claim 23.

25. A lithium-ion battery, wherein, The lithium-ion battery includes the negative electrode as described in claim 24.

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