Fluorine-containing high polymer carbonized and coated silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention discloses a fluorine-containing high polymer carbonized and coated silicon-carbon negative electrode material and a preparation method thereof. The silicon-carbon negative electrode material comprises a silicon-carbon material serving as a core and a coating layer serving as a shell and coating the surface of the silicon-carbon material, wherein the coating layer is formed by carbonizing a fluorine-containing high polymer layer; the fluorine-containing high polymer layer is obtained by coating the surface of the silicon-carbon material with a fluorine-containing micromolecular monomer through in-situ polymerization, or obtained by directly coating the surface of the silicon-carbon material with a fluorine-containing high-molecular polymer, or obtained by coating the surface of the silicon-carbon material with the fluorine-containing micromolecular monomer and a copolymer monomer through in-situ copolymerization. According to the fluorine-containing high polymer carbonized and coated silicon-carbon negative electrode material provided by the invention, the surface of the silicon-carbon material is secondarily coated with the fluorine-doped carbon layer (coating layer), so that the problem that the existing secondarily coated carbon layer can hinder ion transmission of the silicon-carbon material and influence the rate capability can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon-carbon negative electrode materials, and particularly relates to a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of new energy vehicles, the updating of battery technology is also more and more frequent. The charging and discharging time, capacity, cold and heat adaptability and safety of the battery are the focus.

[0003] At present, improving the performance of the negative electrode is an important way to improve the performance of the battery. Silicon negative electrode is widely concerned due to its high theoretical specific capacity, high energy density and easy lithium ion extraction and insertion. At present, there are mainly silicon-carbon composite, silicon-oxygen composite and nanometer technology. The silicon-carbon material is prepared by using the gas phase deposition method (CVD), which can ensure the uniformity of silicon deposition and accurately control the silicon content, and the silicon-carbon material meeting the requirements can be prepared. However, the silicon activity coated by the gas phase deposition method needs to be coated with a carbon layer for the second time to ensure the electrochemical performance and safety, but the secondary coated carbon layer will hinder the ion transmission and affect the rate performance. Therefore, while ensuring the safety and electrochemical performance, it is also necessary to pay attention to improving the ion transmission capacity of the silicon-carbon material.

[0004] The doping of heteroatoms (nitrogen, phosphorus, boron, fluorine, etc.) can effectively improve the ion transmission capacity of the silicon-carbon substrate, and the effect of fluorine doping is excellent. The fluorine element can be uniformly doped into the carbon layer structure by using CVD coating. However, the fluorine-containing gas source is expensive, and there are risks in transportation, installation and use, which is difficult to produce in large quantities safely. Therefore, it is necessary to select a more suitable coating method and coating material, and the high molecular polymer has good ductility and flexibility, which is a relatively ideal coating material, but how to dope the fluorine atoms in the fluorine-containing high molecular polymer into the silicon-carbon becomes a problem to be solved. SUMMARY

[0005] The present application aims to provide a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material and a preparation method thereof, and aims to solve the problem that the ion transmission capacity of the silicon-carbon material prepared by the existing gas phase deposition method is not good, which affects the rate performance and thus affects the performance of the negative electrode (specific capacity, first charge and discharge efficiency, etc.).

[0006] To achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0007] The present application provides a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material, which comprises a silicon-carbon material as a core and a coating layer coated on the surface of the silicon-carbon material as a shell.

[0008] The coating layer is formed by carbonizing a fluorine-containing high polymer layer.

[0009] The fluorine-containing high polymer layer is obtained by in-situ polymerization of fluorine-containing small molecule monomers on the surface of the silicon-carbon material, or by direct coating of fluorine-containing high molecular polymers on the surface of the silicon-carbon material, or by in-situ copolymerization of the fluorine-containing small molecule monomers and copolymer monomers on the surface of the silicon-carbon material.

[0010] Further, the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: the fluorine-containing small molecule monomer adopts fluorinated acrylate, which is specifically selected from any one or a combination of several of methyl trifluoroacrylate, heptafluorobutyric acid, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, tetrafluoropropyl acrylate, hexafluoroisopropyl methacrylate, trifluoromethoxyethyl acrylate, trifluoroethoxyethyl methacrylate.

[0011] Further, the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: the fluorine-containing high molecular polymer is selected from one or a combination of several of polyvinylidene fluoride, perfluoropolyether diol, perfluoropolyether methacrylate, perfluoroepoxidized polyether.

[0012] Specifically, the polyvinylidene fluoride is selected from polyvinylidene fluoride with a molecular weight of 100000-270000, and typical molecular weights are, for example, 100000, 200000, 300000, 400000, 600000, 800000, 1200000, 240000, etc. The perfluoropolyether diol is selected from perfluoropolyether diol (molecular weight 1000-6000, for example, molecular weight 1000, 2000, 3000, 5000, 6000, etc.). The perfluoropolyether methacrylate is selected from perfluoropolyether methacrylate (molecular weight 1000-5000, for example, molecular weight 1000, 2000, 3000, 4000 or 5000, etc.). The perfluoroepoxidized polyether is selected from perfluoroepoxidized polyether (molecular weight 500-16000, for example, molecular weight 500, 1000, 5000 or 10000).

[0013] Further, the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: the copolymer monomer is selected from one or a combination of several of acrylic acid, N,N-methylene bisacrylamide, pyrrole, pyridine, aniline.

[0014] The application also provides a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material, which comprises the following steps:

[0015] S1, coating of the fluorine-containing high polymer layer on the surface of the silicon-carbon material, which comprises the following modes:

[0016] ① In-situ polymerization of fluorine-containing small molecule monomers: the fluorine-containing small molecule monomers and silicon-carbon material are added to organic solvent A for wet mixing, and initiator A is added for in-situ polymerization, and then the organic solvent A is removed to obtain a silicon-carbon material coated with a fluorine-containing polymer layer;

[0017] ② Direct coating of fluorine-containing polymer: the fluorine-containing polymer and silicon-carbon material are added to organic solvent B for wet mixing, and then the organic solvent B is removed to obtain a silicon-carbon material coated with a fluorine-containing polymer layer;

[0018] ③ Co-polymerization coating: the fluorine-containing small molecule monomers, co-polymer monomers and silicon-carbon material are added to organic solvent C for wet mixing, and initiator C is added for in-situ co-polymerization, and then the organic solvent C is removed to obtain a silicon-carbon material coated with a fluorine-containing polymer layer;

[0019] S2, carbonization: the obtained silicon-carbon material coated with a fluorine-containing polymer layer is carbonized at high temperature to obtain a silicon-carbon negative electrode material coated with a carbonized fluorine-containing polymer.

[0020] Specifically, in method ①, the temperature of in-situ polymerization can be controlled at 50-90℃, the in-situ polymerization time is controlled at 4-12 hours, and after removing the organic solvent A by filtration, the silicon-carbon material coated with in-situ polymerized fluorine-containing small molecules is dried at 80-120℃ for 12-24 hours.

[0021] In method ②, the mixing time of the fluorine-containing polymer and the silicon-carbon material is controlled at 8-48 hours; when removing the organic solvent B, the rotary evaporation recovery treatment of the organic solvent B can be performed according to the boiling point of the solvent under vacuum, and then the silicon-carbon material coated with the fluorine-containing polymer is recovered and dried at 80-200℃.

[0022] In method ③, the temperature of in-situ co-polymerization is controlled at 50-90℃, the co-polymerization time is controlled at 4-12 hours, and after removing the organic solvent C by filtration, the silicon-carbon material coated with co-polymer is dried at 80-120℃ for 12-24 hours.

[0023] Specifically, the organic solvent A can be selected from one or a mixture of several of N-methyl pyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, ethanol, methanol, ethylene glycol, isopropanol, acetone, tetrahydrofuran, glycerol.

[0024] The organic solvent B can be selected from one or a mixture of several of dimethyl sulfoxide, dichloromethane, trichloromethane, tetrachloromethane, methanol, ethanol, ethylene glycol, propanol, isopropanol, glycerol, petroleum ether, N-methyl pyrrolidone, N,N-dimethylformamide, acetone.

[0025] The organic solvent C can be selected from one or a mixture of several of N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, ethanol, methanol, ethylene glycol, isopropanol, acetone, tetrahydrofuran, glycerol.

[0026] Further, a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: taking the total mass of the fluorine-containing small molecule monomer, the silicon-carbon material and the initiator A as 100%, the proportion of the fluorine-containing small molecule monomer is 5-20%, the proportion of the silicon-carbon material is 70-90%, and the rest is the initiator A.

[0027] Further, a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: taking the total mass of the fluorine-containing high molecular polymer and the silicon-carbon material as 100%, the proportion of the fluorine-containing high molecular polymer is 10-20%.

[0028] Further, a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: taking the total mass of the fluorine-containing small molecule monomer, the copolymer monomer, the silicon-carbon material and the initiator C as 100%, the proportion of the fluorine-containing small molecule monomer is 10-20%, the proportion of the copolymer monomer is 1-5%, the proportion of the silicon-carbon material is 70-80%, and the proportion of the initiator C is 1-12%.

[0029] Further, a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: the initiator A and the initiator C are respectively selected from any one or a combination of several of sodium percarbonate, ammonium persulfate, potassium persulfate, sodium peroxide, tert-butyl hydroperoxide, benzoyl peroxide, dibenzoyl peroxide, peroxycyclohexanone, peroxoacetic acid and aluminum isopropyl alcohol.

[0030] Further, a preparation method of the fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material: after being heated to 300-500 DEG C and kept for 1-5 hours, carbonization is carried out.

[0031] The beneficial effects of the present application are:

[0032] The fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material provided by the present application can solve the problem that the existing secondary coated carbon layer hinders the ion transmission of the silicon-carbon material and affects the rate performance by secondary coating a fluorine-doped carbon layer (coating layer) on the surface of the silicon-carbon material.

[0033] In addition, the application further provides a preparation method of the silicon-carbon negative electrode material coated by fluorine-containing polymer carbonization, which can be coated by in-situ polymerization of fluorine-containing small molecule monomers. The in-situ polymerization of small molecules can grow on the surface of the silicon-carbon material and adhere to the silicon-carbon particles, so that the coating layer is more compact, and the fluorine element is more uniformly doped after carbonization. The direct coating of fluorine-containing polymer can make the molecular weight of the coating layer high, the residual carbon content after carbonization large, and the coating layer have high mechanical strength and be more stable. The coating by copolymerization can make the combination of the coating layer and the silicon-carbon material more compact, so as to promote the strength of the coating layer and the uniform doping of the fluorine element after carbonization. Therefore, the preparation method provided by the application can realize the more uniform doping of fluorine atoms in the surface coating layer of the silicon-carbon material, and promote the improvement of the ion transmission capacity of the silicon-carbon negative electrode material. DETAILED DESCRIPTION

[0034] The technical solutions of the application will be described clearly and completely below in combination with specific embodiments. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. The following description of at least one example embodiment is merely illustrative, but not any limitation on the application and its application or use. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0035] Embodiment 1

[0036] The embodiment 1 provides a silicon-carbon negative electrode material coated by fluorine-containing polymer carbonization, which comprises a silicon-carbon material as a core and a coating layer coated on the surface of the silicon-carbon material as a shell.

[0037] The coating layer is formed by carbonization of a fluorine-containing polymer layer, and the fluorine-containing polymer layer is obtained by in-situ polymerization of fluorine-containing small molecule monomers on the surface of the silicon-carbon material.

[0038] The preparation method of the silicon-carbon negative electrode material coated by fluorine-containing polymer carbonization in the above embodiment 1 comprises the following specific steps:

[0039] S1, in-situ polymerization of fluorine-containing small molecule monomers: 1.0 g of 2,2,3,3,3-pentafluoropropyl acrylate (fluorine-containing small molecule monomer) is dissolved in 50.0 ml of ethanol (machine solvent A), and 5.0 g of silicon-carbon material is added for mixing under the condition of stirring at a speed of 300 rpm to obtain a silicon-carbon mixed solution, which is placed in a constant temperature reaction kettle at 60℃.

[0040] Take 0.5 g of sodium percarbonate (initiator A) and dissolve it in 50.0 ml of water, and stir at a rate of 300 rpm until the sodium percarbonate is completely dissolved; then add the sodium percarbonate solution to the silicon-carbon mixed solution, increase the stirring speed to 500 rpm, and continue stirring in a constant-temperature reaction kettle at 60°C for 8 hours to obtain a suspension of small-molecule in-situ polymerization coated silicon-carbon material;

[0041] The suspension is subjected to solid-liquid separation, the organic solvent A is discarded, and the solid product is collected and dried by blowing to remove the moisture of the solid product, thereby obtaining a fluorine-containing polymer layer coated silicon-carbon material;

[0042] S2, carbonization: the obtained fluorine-containing polymer layer coated silicon-carbon material is placed in a carbonization furnace, the heating rate is set to 2°C / min, the temperature is raised to 400°C, and the temperature is kept for 1 hour, and then the material is collected after cooling, thereby obtaining a fluorine-containing polymer carbonized coated silicon-carbon negative electrode material.

[0043] Example 2

[0044] The difference between Example 2 and Example 1 is that the fluorine-containing small-molecule monomer used in Example 2 is different from that in Example 1, and Example 2 uses 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, and the rest of the conditions are the same as in Example 1.

[0045] Example 3

[0046] The difference between Example 3 and Example 1 is that the fluorine-containing small-molecule monomer used in Example 3 is different from that in Example 1, and Example 3 uses tetrafluoropropyl acrylate, and the rest of the conditions are the same as in Example 1.

[0047] Example 4

[0048] The difference between Example 4 and Example 1 is that the fluorine-containing small-molecule monomer used in Example 4 is different from that in Example 1, and Example 4 uses 2,2,3,4,4,4-hexafluorobutyl acrylate, and the rest of the conditions are the same as in Example 1.

[0049] Example 5

[0050] The difference between Example 5 and Example 1 is that the initiator A used in Example 5 is different from that in Example 1, and Example 5 specifically uses ammonium persulfate initiator, and the rest of the conditions are the same as in Example 1.

[0051] Example 6

[0052] The difference between Example 6 and Example 1 is that the amount of sodium percarbonate added in Example 6 is different from that in Example 1, and Example 6 adds 0.3 g of sodium percarbonate, and the rest of the conditions are the same as in Example 1.

[0053] Example 7

[0054] Example 7 differs from Example 1 in that the carbonization temperature of Example 7 is different from Example 1, and Example 7 is carbonized at 500℃, and the rest of the conditions are the same as Example 1.

[0055] Example 8

[0056] Example 8 provides a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material, which comprises a silicon-carbon material as a core and a coating layer coated on the surface of the silicon-carbon material as a shell.

[0057] The coating layer is formed by carbonization of a fluorine-containing high polymer layer, and the fluorine-containing high polymer layer is obtained by directly coating a fluorine-containing high molecular polymer on the surface of the silicon-carbon material.

[0058] The preparation method of the above-mentioned fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material of Example 8 comprises the following specific steps:

[0059] S1, directly coating a fluorine-containing high molecular polymer: 1.0 g of polyvinylidene fluoride (molecular weight 200000) is added to 50.0 ml of N-methyl pyrrolidone (organic solvent B) and stirred to dissolve at a speed of 300 rpm, and then 5.0 g of silicon-carbon material is added, and stirring is continued at a speed of 300 rpm for 2 hours. After stirring is completed, the mixed solution is transferred to a rotary evaporator, vacuum reduced to 0.1 MPa, and evaporated and dried at 100℃. After the organic solvent B is completely evaporated, the product is dried at 110℃ for 18 hours, and the residual solvent is removed. Finally, a silicon-carbon material coated with a fluorine-containing high polymer layer is obtained.

[0060] S2, carbonization: the obtained silicon-carbon material coated with a fluorine-containing high polymer layer is placed in a carbonization furnace, the heating rate is set to 3℃ / min, the temperature is raised to 330℃, and the temperature is kept for 5 hours. After cooling, the material is collected to obtain a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material.

[0061] Example 9

[0062] Example 9 differs from Example 8 in that the fluorine-containing high molecular polymer used in Example 9 is different from Example 8, and Example 9 uses perfluoropolyether diol (molecular weight 2000) as a fluorine-containing high molecular polymer, and the rest of the conditions are the same as Example 8.

[0063] Example 10

[0064] Example 10 differs from Example 8 in that the fluorine-containing high molecular polymer used in Example 10 is different from Example 8, and Example 10 uses perfluoroepoxidized polyether (molecular weight 5000) as a fluorine-containing high molecular polymer, and the rest of the conditions are the same as Example 8.

[0065] Example 11

[0066] Example 11 differs from Example 8 in that Example 11 uses polyvinylidene fluoride with a molecular weight of 300000, and the rest of the conditions are the same as Example 8.

[0067] Example 12

[0068] Example 12 differs from Example 9 in that Example 12 uses perfluoropolyether diol with a molecular weight of 4000, and the rest of the conditions are the same as Example 9.

[0069] Example 13

[0070] The present embodiment 13 provides a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material, which comprises a silicon-carbon material as a core and a coating layer coated on the surface of the silicon-carbon material as a shell;

[0071] Wherein, the coating layer is formed by carbonization of a fluorine-containing high polymer layer, and the fluorine-containing high polymer layer is obtained by in-situ copolymerization of fluorine-containing small molecule monomers and copolymer monomers on the surface of the silicon-carbon material;

[0072] The preparation method of the above-mentioned fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material of embodiment 13 comprises the following specific steps:

[0073] S1, copolymerization coating: 1.0g of 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (fluorine-containing small molecule monomer) and 0.1g of acrylic acid (copolymer monomer) are dissolved in 50.0ml of ethanol (machine solvent C), and 5.0g of silicon-carbon material is added under stirring at a speed of 300rpm to obtain a mixed solution, which is placed in a constant temperature reaction kettle at 60℃;

[0074] 0.8g of sodium percarbonate (initiator C) is dissolved in 50.0ml of water and stirred at a speed of 300rpm until the sodium percarbonate is completely dissolved; then the sodium percarbonate solution is added to the above-mentioned mixed solution, and the stirring speed is increased to 500rpm, and the in-situ copolymerization is carried out in a constant temperature reaction kettle at 60℃ for 8 hours, to obtain a suspension;

[0075] The suspension is subjected to solid-liquid separation, and the organic solvent C is discarded, and the solid product is collected, and the moisture of the solid product is removed by air blowing drying to obtain a silicon-carbon material coated with a fluorine-containing high polymer layer;

[0076] S2, carbonization: the obtained silicon-carbon material coated with a fluorine-containing high polymer layer is placed in a carbonization furnace, the heating rate is set to 2℃ / min, the temperature is raised to 400℃, and the temperature is kept for 2 hours, then the temperature is lowered to obtain a fluorine-containing high polymer carbonized coated silicon-carbon negative electrode material.

[0077] Example 14

[0078] Example 14 differs from Example 13 in that the amount of 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (fluorine-containing small molecule monomer) added in Example 14 is different from that in Example 13, and 0.5 g of 2,2,3,3,4,4,4-heptafluorobutyl methacrylate is added in Example 14, and the rest of the conditions are the same as those in Example 13.

[0079] Comparative Example 1

[0080] Comparative Example 1 differs from Example 1 in that Comparative Example 1 is not subjected to high-temperature carbonization, and the rest of the conditions are the same as those in Example 1.

[0081] Comparative Example 2

[0082] Silicon-carbon material (Si@C) is used as a comparison.

[0083] Test:

[0084] The silicon-carbon negative electrode materials obtained in Examples 1 to 14 and Comparative Examples 1 and 2 are subjected to a discharge test and an electrochemical test, and D Li+ (lithium ion transmission coefficient) is calculated. Li+ The higher the value, the stronger the ion transmission ability, and the higher the rate performance. The specific results are shown in Table 1 below:

[0085] Table 1 shows the performance test results of the silicon-carbon negative electrode materials of Examples 1 to 14 and Comparative Examples 1 and 2.

[0086] Specific capacity (mAh / g) Initial coulombic efficiency (%) D Li+ (·10 -14 )]]> Example 1 2025 92.2 5.04 Example 2 1999 92.0 4.12 Example 3 2055 92.5 6.98 Example 4 2088 92.1 6.87 Example 5 2103 92.1 6.78 Example 6 1980 91.6 5.33 Example 7 1973 91.2 5.86 Example 8 1898 91.1 4.97 Example 9 1975 91.6 4.29 Example 10 1990 91.5 6.12 Example 11 1962 91.3 6.07 Example 12 1983 91.7 5.43 Example 13 2034 91.0 7.13 Example 14 2156 92.8 5.24 Comparative Example 1 1768 89.2 4.89 Comparative Example 2 1939 90.1 0.12

[0087] As can be seen from the test results of Example 1 and Comparative Example 1 in Table 1, the ion transmission ability of the material after carbonization is higher than that before carbonization, because carbonization promotes the more uniform doping of fluorine atoms in the coating layer, thereby improving the ion transmission ability, and the specific capacity and the initial efficiency of the material after carbonization are higher than those before carbonization. As can be seen from the test results of Example and Comparative Example 2, the silicon-carbon negative electrode material coated with fluorine-containing high polymer prepared by the present application can significantly improve the specific capacity and the initial coulombic efficiency of the material.

[0088] The above is the preferred embodiment of the present application, which is only used to explain the present application, and does not limit the present application. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A silicon-carbon anode material coated with fluorinated polymer, characterized in that, The silicon-carbon anode material includes a silicon-carbon material as the core and a coating layer covering the surface of the silicon-carbon material as an outer shell; The coating layer is formed by carbonization of a fluorinated polymer layer; The fluorinated polymer layer is obtained by in-situ polymerization of fluorinated small molecule monomers onto the surface of the silicon-carbon material, or by directly coating the surface of the silicon-carbon material with a fluorinated polymer, or by in-situ copolymerization of the fluorinated small molecule monomers and copolymer monomers onto the surface of the silicon-carbon material.

2. The silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 1, characterized in that, The fluorinated small molecule monomer is a fluorinated acrylate, specifically selected from any one or a combination of several of the following: trifluoroethyl methacrylate, heptafluorobutyric acid, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, tetrafluoropropyl acrylate, hexafluoroisopropyl methacrylate, trifluoromethoxyethyl acrylate, and trifluoroethoxyethyl methacrylate.

3. The silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 1, characterized in that, The fluorinated polymer is selected from one or a combination of several of the following: polyvinylidene fluoride, perfluoropolyether glycol, perfluoropolyether methacrylate, and perfluoroepoxy polyether.

4. The silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 1, characterized in that, The copolymer monomer is selected from one or a combination of several of acrylic acid, N,N-methylenebisacrylamide, pyrrole, pyridine, and aniline.

5. A method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to any one of claims 1 to 4, characterized in that, The method includes the following steps: S1. Coating of silicon-carbon material surfaces with fluorinated polymer layers, including the following methods: ① In-situ polymerization and coating of fluorinated small molecule monomers: Fluorinated small molecule monomers and silicon carbon materials are added to organic solvent A for wet mixing, and initiator A is added for in-situ polymerization. Then, organic solvent A is removed to obtain silicon carbon materials coated with fluorinated polymer layers. ② Direct coating with fluorinated polymer: Fluorinated polymer and silicon carbon material are added to organic solvent B for wet mixing. After obtaining the mixed slurry, organic solvent B is removed to obtain silicon carbon material coated with fluorinated polymer layer. ③ Copolymer coating: Fluorine-containing small molecule monomers, copolymer monomers and silicon carbon materials are added to organic solvent C for wet mixing, and initiator C is added for in-situ copolymerization. After copolymerization, organic solvent C is removed to obtain silicon carbon materials coated with fluorine-containing polymer layers. S2, Carbonization: The silicon-carbon material coated with the obtained fluorinated polymer layer is carbonized at high temperature to obtain silicon-carbon anode material coated with fluorinated polymer carbonization.

6. The method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 5, characterized in that, Based on the total mass of fluorinated small molecule monomers, silicon carbon materials and initiator A, which is 100%, the proportion of fluorinated small molecule monomers is 5-20%, the proportion of silicon carbon materials is 70-90%, and the balance is initiator A.

7. The method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 5, characterized in that, Based on the total mass of fluorinated polymer and silicon carbon materials, which is 100%, the proportion of fluorinated polymer is 10-20%.

8. The method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 5, characterized in that, Based on the total mass of fluorinated small molecule monomers, copolymer monomers, silicon carbon materials, and initiator C, which is 100%, the proportion of fluorinated small molecule monomers is 10-20%, the proportion of copolymer monomers is 1-5%, the proportion of silicon carbon materials is 70-80%, and the proportion of initiator C is 1-12%.

9. The method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 5, characterized in that, The initiator A and initiator C are respectively selected from any one or a combination of several of sodium percarbonate, ammonium persulfate, potassium persulfate, sodium peroxide, tert-butyl hydroperoxide, benzoyl peroxide, dibenzoyl peroxide, peroxycycloacetone, peracetic acid, and aluminum isopropoxide.

10. The method for preparing a silicon-carbon anode material with fluorinated polymer carbonization coating according to claim 5, characterized in that, Carbonization is carried out by heating to 300-500℃ and holding at that temperature for 1-5 hours.