Silicon-carbon negative electrode material and preparation method thereof
By using porous carbonation treatment and preparing metal sulfide/silicon composite materials, the problems of volume expansion and insufficient conductivity of silicon-carbon anode materials were solved, achieving a high-efficiency improvement in lithium-ion battery performance, especially in terms of first-time coulombic efficiency and cycle life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEFEI GUOXUAN HIGH TECH POWER ENERGY
- Filing Date
- 2024-05-09
- Publication Date
- 2026-06-16
AI Technical Summary
Existing silicon-carbon anode materials suffer from volume expansion and insufficient conductivity in lithium-ion batteries, which limits the increase of silicon content and cycle stability, resulting in poor battery performance.
Through porous carbonation treatment, ultrasonic dispersion, addition of metal chloride and thioacetamide, mixing, addition of liquid silicon source and hydrothermal treatment, followed by reaction with boron-containing gel, metal sulfide/silicon composite material and boron-containing carbon nanotubes are formed. Finally, sintering is carried out in an inert atmosphere to form a silicon-carbon anode material with low expansion and high conductivity.
It effectively improves the initial coulombic efficiency and cycle life of lithium-ion batteries, while the process is simple and safe. Porous carbon limits volume expansion, metal sulfides improve conductivity, and boron-containing carbon nanotubes improve electron and lithium-ion kinetics.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a silicon-carbon anode material and its preparation method. Background Technology
[0002] With the rapid development of energy storage devices, the demand for high capacity and high power in lithium-ion batteries (LIBs) is becoming increasingly urgent. Silicon / carbon (Si / C) anodes have advantages such as high process compatibility, low cost, and high specific capacity, and are considered promising for next-generation lithium-ion batteries. However, silicon materials undergo significant volume expansion during lithium insertion / extraction, and silicon's inherent electronic conductivity is insufficient. These issues limit the silicon content in Si / C anodes to below 15 wt%. Maintaining cycle stability while increasing silicon content is a key challenge in this field. To address the challenges of achieving high-silicon-content electrodes and improving the cycle performance of silicon / carbon anodes, two factors must be considered: cycle volume expansion and establishing a robust electronic conductivity network. Previous studies have proposed various strategies to achieve this goal, including nanostructuring and coating. However, the inevitable periodic volume expansion during cycling can lead to a break in the contact between conductive additives and silicon. Furthermore, this contact condition may deteriorate with increasing cycle count, eventually leading to battery failure. Therefore, the key issue is to design a conductive system that can achieve a robust electronic conductivity network while accommodating the periodic volume expansion of high silicon content.
[0003] Currently, the silicon anodes used in commercial batteries are mainly silicon-oxygen anodes, which have low capacity and poor cycle life. Even after simple coating, the conductivity of the materials remains poor, and the volume expansion problem still lacks a good solution. Therefore, we propose a simple silicon-carbon anode material with excellent cycle performance and conductivity, along with its preparation method. Summary of the Invention
[0004] The purpose of this invention is to provide a silicon-carbon anode material and its preparation method, which solves the problem of volume expansion and improves conductivity. This silicon-carbon anode material can effectively improve the first coulombic efficiency and cycle life of the battery, and the process is simple and safe.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] In a first aspect, the present invention provides a method for preparing a silicon-carbon anode material, comprising the following steps:
[0007] S1. The porous carbon is immersed in an acidic treatment solution for acidification treatment to obtain material A;
[0008] S2. Add metal chloride and thioacetamide to material A and mix to obtain material B;
[0009] S3. Add liquid silicon source to material B, mix and then perform hydrothermal treatment under inert gas protection to obtain material C;
[0010] S4. Add a boron-containing gel solvent composed of deionized water, organic polymer and boron-containing substances to the material C to react. After the reaction is complete, dry the material to obtain material D.
[0011] S5. Sinter the material D under an inert atmosphere to obtain the silicon-carbon anode material.
[0012] In the above-mentioned method for preparing silicon-carbon anode materials, the pore size of the porous carbon can be 2-5 nm, specifically 2 nm;
[0013] The porous carbon may specifically be coconut shell carbon;
[0014] The alcohol solvent is one or more of ethanol, methanol, isopropanol, benzyl alcohol, and ethylene glycol;
[0015] The acidic reagent is one or more of hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, and nitric acid;
[0016] The pH of the acidic reagent is 1;
[0017] The mass ratio of the porous carbon to the acidic reagent can be (2-10):1, specifically (2-5):1, 5:1 or 2:1;
[0018] The mass ratio of the alcohol solvent to the acid reagent can be (2-10):1, specifically 9:1;
[0019] The acidification treatment is carried out under stirring conditions, with a stirring speed of 300-800 r / min, specifically 300 r / min, 500 r / min, or 800 r / min, and a stirring time of 5-20 min, specifically 10-20 min, 10 min, or 20 min.
[0020] Step S1 also includes ultrasonic dispersion of the acidified system. The ultrasonic power can be 100-400W, specifically 100W, 200W, 300W, or 400W, and the time can be 10-30 minutes, specifically 10 minutes.
[0021] In the above-mentioned method for preparing silicon-carbon anode materials, the metal chloride is one or more of ferrous chloride, silver chloride, tin chloride, copper chloride, lithium chloride, zinc chloride, and aluminum chloride;
[0022] The thioacetamide has a purity of 98% or higher, such as 99%.
[0023] The mass ratio of the metal chloride to the thioacetamide can be 1:(1-10), specifically 1:(1-2), 1:1 or 1:2;
[0024] The mass ratio of material A to the metal chloride can be (10-20):1, specifically (12-15):1, 15:1 or 12:1;
[0025] The mixing in step S2 is carried out under stirring conditions. The stirring speed can be 300-1000 r / min, such as 500 r / min, and the stirring time can be 30-60 min, such as 30 min.
[0026] In the above-mentioned method for preparing silicon-carbon anode materials, the liquid silicon source is one or more of silicon tetrachloride, methyl orthosilicate, ethyl orthosilicate, tetramethylcyclotetrasiloxane, and octamethylcyclotetrasiloxane.
[0027] The mass ratio of material B to the liquid silicon source can be (2-10):1, specifically (3-5):1, 4.25:1, or 3.75:1.
[0028] The mixing described in step S3 is carried out under stirring conditions. The stirring speed can be 500 to 1500 r / min, specifically 500 r / min, 1000 r / min, or 1500 r / min, and the time can be 1 to 5 hours, such as 2 hours.
[0029] The inert gas may be at least one of helium, argon, and nitrogen;
[0030] The hydrothermal treatment temperature can be 100-300℃, and the treatment time can be 12-24h, such as hydrothermal reaction at 200℃-300℃, 200℃ or 300℃ for 24h.
[0031] In the above-mentioned method for preparing silicon-carbon anode materials, step S3 further includes ball milling the hydrothermally treated system.
[0032] The ball milling process can be high-energy ball milling (e.g., placed in a planetary ball mill), with a rotation speed of 1000-2000 r / min, such as 1000 r / min or 2000 r / min, and a milling time of 12-24 h, such as 14 h or 24 h.
[0033] In the above-mentioned method for preparing silicon-carbon anode materials, the organic polymer is at least one of polyvinyl alcohol, polyvinyl butyral, sodium carboxymethyl cellulose, epoxy resin, and phenolic resin.
[0034] The boron-containing substance is at least one of boric acid, borax, boron oxide, and sodium metaborate;
[0035] The mass ratio of the organic polymer to the boron-containing substance can be (1-10):1, specifically (1-2):1, 2:1, or 1:1.
[0036] The mass percentage of the deionized water in the boron-containing gel solvent can be 50% to 80%, specifically 67% or 71%.
[0037] The mass ratio of material C to the boron-containing substance can be (1-20):1, specifically (1-2):1, 2:1, or 1:1.
[0038] The reaction described in step S4 is carried out under stirring conditions. The stirring speed can be 300-800 r / min, and the time can be 2-8 h, such as stirring at 800 r / min for 2 h.
[0039] In the above-mentioned method for preparing low-expansion, high-conductivity silicon-carbon anode materials, the drying process is freeze-drying.
[0040] The freeze-drying time can be 12 to 24 hours, such as 24 hours, and the drying temperature can be -30 to -50°C, such as -50°C.
[0041] In the above-mentioned method for preparing silicon-carbon anode materials, the inert atmosphere is at least one of helium, argon, and nitrogen.
[0042] The sintering temperature can be 500–1000℃, such as 600–700℃, 600℃ or 700℃, and the time can be 1–12 hours, specifically 12 hours.
[0043] Secondly, the present invention provides a silicon-carbon anode material obtained by any of the preparation methods described above.
[0044] Thirdly, the present invention provides a lithium-ion battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the negative electrode comprises the aforementioned silicon-carbon negative electrode material.
[0045] The present invention has the following beneficial effects:
[0046] The method of this invention first involves porous carbonization, followed by ultrasonic dispersion, the addition of metal chlorides and thioacetamide, mixing and stirring, then adding a liquid silicon source, followed by secondary stirring and hydrothermal treatment. After discharge, the material is subjected to high-energy ball milling, mixed and stirred with a boron-containing gel, freeze-dried, and calcined in a tube furnace to form a low-expansion, high-conductivity silicon-carbon material. The porous carbon provides a support for the silicon source and restricts the volume expansion of silicon. The introduction of metal chlorides and thioacetamide forms a metal sulfide / silicon composite material. During lithium insertion / extraction, the formed metal enhances the conductivity of the silicon material. The lithium sulfide formed by sulfide conversion further improves the mechanical stability and lithium-ion transport rate of the SEI film and effectively restricts the volume expansion of the silicon material. Simultaneously, under the catalysis of the formed metal, the boron-containing gel forms boron-containing carbon nanotubes. Boron doping helps improve electron and lithium-ion kinetics, and the carbon nanotubes can regulate the volume change of silicon during lithium insertion / extraction and enhance the conductivity of the particles. The silicon-carbon anode material prepared by this invention can effectively improve the first coulombic efficiency and cycle life of the battery, and the process is simple and safe. Attached Figure Description
[0047] Figure 1 The above are the SEM test results of the silicon-carbon anode material prepared in Example 1 of this invention.
[0048] Figure 2 This is a resistivity comparison diagram of the silicon-carbon anode material prepared in Example 1 of the present invention and the commercial SiO / C materials of Comparative Examples 1-3.
[0049] Figure 3 The results show the charge-discharge capacity test results of the silicon-carbon anode material prepared in Example 1 of this invention and the commercial SiO / C material in Comparative Example 1.
[0050] Figure 4 The cycling performance test results are shown for the silicon-carbon anode material prepared in Example 1 of this invention and the commercial SiO / C material in Comparative Example 1. Detailed Implementation
[0051] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.
[0052] Unless otherwise specified, the methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.
[0053] Example 1: Preparation of silicon-carbon anode material
[0054] Novel silicon-carbon anode materials were prepared according to the following steps:
[0055] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 250g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir at 800r / min for 20min and then ultrasonically disperse for 10min (ultrasonic power of 400W) to obtain material A.
[0056] S2. Add 50g of tin chloride and 50g of thioacetamide (purity 99%) to material A, then stir with a high-speed mixer at 500r / min for 30min to obtain material B.
[0057] S3. Add 200g of silicon tetrachloride to material B, stir for 2 hours (stirring speed is 1000r / min), then place it in a hydrothermal reactor, introduce argon gas, and hydrothermally react at 200℃ for 24 hours. After cooling, take it out and place it in a planetary ball mill. After ball milling at 1000r / min for 14 hours, material C is obtained.
[0058] S4. Place 100g of polyvinyl alcohol and 50g of boric acid in 300g of deionized water, add 100g of material C, stir and react for 2h (stirring speed is 800r / min), then place in a freeze dryer and freeze at -50℃ for 24h to obtain material D;
[0059] S5. Place material D in a tube furnace, introduce argon gas, heat and sinter at 600℃ for 12 hours, and then cool to obtain the final product.
[0060] Example 2: Preparation of silicon-carbon anode material
[0061] Novel silicon-carbon anode materials were prepared according to the following steps:
[0062] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 100g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir at 500r / min for 20min and then ultrasonically disperse for 10min (ultrasonic power of 300W) to obtain material A.
[0063] S2. Add 50g of silver chloride and 100g of thioacetamide (purity 98%) to material A, then stir with a high-speed mixer at 500r / min for 30min to obtain material B.
[0064] S3. Add 200g of silicon tetrachloride to material B, stir for 2 hours (stirring speed is 1500r / min), then place it in a hydrothermal reactor, introduce argon gas, and hydrothermally react at 200℃ for 24 hours. After cooling, take it out and place it in a planetary ball mill. After ball milling at 1000r / min for 14 hours, material C is obtained.
[0065] S4. Place 100g of polyvinyl alcohol and 50g of boric acid in 300g of deionized water, add 100g of material C, stir and react for 2h (stirring speed is 300r / min), then place in a freeze dryer and freeze at -50℃ for 24h to obtain material D;
[0066] S5. Place material D in a tube furnace, introduce argon gas, heat and sinter at 600℃ for 12 hours, and then cool to obtain the final product.
[0067] Example 3: Preparation of silicon-carbon anode material
[0068] Novel silicon-carbon anode materials were prepared according to the following steps:
[0069] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 100g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir at 300r / min for 20min, and then ultrasonically disperse for 10min with an ultrasonic power of 100W to obtain material A.
[0070] S2. Add 50g of silver chloride and 100g of thioacetamide (purity 99%) to material A, then stir with a high-speed mixer at 500r / min for 30min to obtain material B.
[0071] S3. Add 200g of tetraethyl orthosilicate to material B, stir for 2 hours (stirring speed is 500r / min), then place it in a hydrothermal reactor, introduce argon gas, and hydrothermally react at 300℃ for 24 hours. After cooling, take it out and place it in a planetary ball mill. Ball mill at 2000r / min for 24 hours to obtain material C.
[0072] S4. Place 100g of polyvinyl alcohol and 50g of boric acid in 300g of deionized water, add 100g of material C, stir and react for 2h (stirring speed is 500r / min), then place in a freeze dryer and freeze at -50℃ for 24h to obtain material D;
[0073] S5. Place material D in a tube furnace, introduce argon gas, heat and sinter at 600℃ for 12 hours, and then cool to obtain the final product.
[0074] Example 4: Preparation of silicon-carbon anode material
[0075] Novel silicon-carbon anode materials were prepared according to the following steps:
[0076] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 250g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir at 500r / min for 20min and then ultrasonically disperse for 10min (ultrasonic power of 200W) to obtain material A.
[0077] S2. Add 50g of tin chloride and 50g of thioacetamide (purity 98%) to material A, then stir with a high-speed mixer at 500r / min for 30min to obtain material B.
[0078] S3. Add 200g of silicon tetrachloride to material B, stir for 2 hours (stirring speed is 1000r / min), then place it in a hydrothermal reactor, introduce argon gas, and hydrothermally react at 200℃ for 24 hours. After cooling, take it out and place it in a planetary ball mill. After ball milling at 1000r / min for 14 hours, material C is obtained.
[0079] S4. Place 100g of polyvinyl butyral and 100g of boron oxide in 500g of deionized water, add 100g of material C, stir and react for 2h (stirring speed is 500r / min), then place in a freeze dryer and freeze at -50℃ for 24h to obtain material D.
[0080] S5. Place material D in a tube furnace, introduce argon gas, heat and sinter at 700℃ for 12 hours, and then cool to obtain the final product.
[0081] Comparative Example 1
[0082] Comparative Example 1 is a commercially available SiO / C material.
[0083] Comparative Example 2
[0084] Preparation of novel silicon-carbon anode materials:
[0085] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 250g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir for 20min and then ultrasonically disperse for 10min to obtain material A.
[0086] S2. Add 200g of silicon tetrachloride to material A, stir for 2 hours, place in a hydrothermal reactor, introduce argon gas, hydrothermally react at 200℃ for 24 hours, cool and take out, place in a planetary ball mill, ball mill at 1000r / min for 14 hours to obtain material C.
[0087] S4. Place 100g of polyvinyl alcohol and 50g of boric acid in 300g of deionized water, add 100g of material C, stir and react for 2 hours, then place in a freeze dryer and freeze at -50℃ for 24 hours to obtain material D.
[0088] S5. Place material D in a tube furnace, introduce argon gas, heat and sinter at 600℃ for 12 hours, and then cool to obtain the final product.
[0089] Comparative Example 3
[0090] Preparation of novel silicon-carbon anode materials:
[0091] S1. Mix 50g of 1mol / L hydrochloric acid and 450g of ethanol in a beaker, then add 250g of porous carbon with a pore size of 2nm (purchased from Fujian Yuanli Activated Carbon Co., Ltd., coconut shell carbon HA series), stir for 20min and then ultrasonically disperse for 10min to obtain material A.
[0092] S2. Add 50g of tin chloride and 50g of thioacetamide to material A, then stir using a high-speed mixer at a speed of 500r / min for 30min to obtain material B.
[0093] S3. Add 200g silicon tetrachloride to material B, stir for 2 hours, place in a hydrothermal reactor, introduce argon gas, hydrothermally react at 200℃ for 24 hours, cool and take out, place in a planetary ball mill, ball mill at 1000r / min for 14 hours to obtain material C.
[0094] S4. Place material C in a tube furnace, introduce argon gas, heat and sinter at 600℃ for 12 hours, and then cool to obtain the final product.
[0095] Test case
[0096] The silicon suboxide anode material prepared in Example 1 was subjected to SEM testing, and the results are as follows: Figure 1 As shown. By Figure 1 As can be seen from the above, the novel silicon-carbon anode material prepared in Example 1 has relatively uniform particle size, with a particle size of approximately 5 μm.
[0097] The electrical conductivity of the materials in Comparative Example 1 and Comparative Examples 1-3 is as follows: Figure 2As shown, the conductivity of the low-expansion, high-conductivity silicon-carbon anode material of this invention is superior to that of the commercially available SiO / C material in Comparative Example 1. Furthermore, the comparison results between Example 1 and Comparative Examples 2-3 show that the conductivity of the silicon-carbon anode material of this invention is superior to that of Comparative Examples 2 and 3. This is because the introduction of metal chloride and thioacetamide in this invention can form a metal sulfide / silicon composite material. During the lithium deintercalation / intercalation process, the formed metal substance can improve the conductivity of the silicon material. The addition of boron-containing gel can form boron-containing carbon nanotubes. Boron doping helps improve electron and lithium-ion dynamics, and the carbon nanotubes can regulate the volume change of silicon during lithium deintercalation / intercalation and enhance the conductivity of the particles.
[0098] The novel silicon-carbon anode materials of Examples 1-4 and Comparative Examples 1-3, and the commercial SiO / C material of Comparative Example 1 were used as anode active materials. A paste was prepared by mixing the anode active material, conductive agent SP, and binder LA133 at a mass ratio of 8:1:1, and then coated onto copper foil to assemble CR2016 coin cells. The cathode was a ternary material NCM811, prepared by mixing the cathode active material, conductive agent SP, and binder PVDF at a mass ratio of 8:1:1, and then coated onto aluminum foil. A 1 mol / L LiPF6 EC + DMC solution was used as the electrolyte, and a PP membrane was used. Electrochemical performance tests were conducted, and the results are shown in Table 1 and 2. Figure 3-4 As shown.
[0099] Table 1. Electrochemical performance test results
[0100]
[0101] From Table 1 and Figure 3-4 The comparison results between the intermediate examples and the comparative examples show that the silicon-carbon anode material prepared by the present invention can effectively improve the initial coulombic efficiency and cycle life of the battery. This is because the introduction of metal chloride and thioacetamide in the present invention can form a metal sulfide / silicon composite material. During the lithium deintercalation / intercalation process, the formed metal substance can improve the conductivity of the silicon material. At the same time, the lithium sulfide formed by the conversion of sulfide can further improve the mechanical stability and lithium-ion transport rate of the SEI film and effectively limit the volume expansion of the silicon material. The addition of boron-containing gel can form boron-containing carbon nanotubes. Boron doping helps to improve electron and lithium-ion dynamics. Carbon nanotubes can regulate the volume change of silicon during lithium deintercalation / intercalation and enhance the conductivity of the particles, thereby effectively improving the initial coulombic efficiency and cycle life of the battery.
[0102] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.
Claims
1. A method for preparing a silicon-carbon anode material, characterized in that, Includes the following steps: S1. The porous carbon is immersed in an acidic treatment solution for acidification treatment to obtain material A; S2. Add metal chloride and thioacetamide to material A and mix to obtain material B; The metal chloride is one or more of ferrous chloride, silver chloride, tin chloride, copper chloride, lithium chloride, zinc chloride, and aluminum chloride; The mass ratio of the metal chloride to the thioacetamide is 1:(1~10). S3. Add liquid silicon source to material B, mix and then perform hydrothermal treatment under inert gas protection to obtain material C; S4. Add a boron-containing gel solvent composed of deionized water, organic polymer and boron-containing substances to the material C to react. After the reaction is complete, dry the material to obtain material D. The organic polymer is at least one of polyvinyl alcohol, polyvinyl butyral, sodium carboxymethyl cellulose, epoxy resin, and phenolic resin. The boron-containing substance is at least one of boric acid, borax, boron oxide, and sodium metaborate; The mass ratio of the organic polymer to the boron-containing substance is (1~10):1; The deionized water in the boron-containing gel solvent is 50% to 80% by mass. The mass ratio of material C to the boron-containing substance is (1~20):1; The reaction described in step S4 is carried out under stirring conditions, with a stirring speed of 300~800 r / min and a time of 2~8 h; S5. Sinter the material D under an inert atmosphere to obtain the silicon-carbon anode material.
2. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: The porous carbon has a pore size of 2~5 nm; The acidic treatment solution is composed of an alcohol solvent and an acidic reagent; The alcohol solvent is one or more of ethanol, methanol, isopropanol, benzyl alcohol, and ethylene glycol; The acidic reagent is one or more of hydrochloric acid, sulfuric acid, acetic acid, phosphoric acid, and nitric acid; The pH of the acidic reagent is 1; The mass ratio of the porous carbon to the acidic reagent is (2~10):1; The mass ratio of the alcohol solvent to the acid reagent is (2~10):1; The acidification treatment is carried out under stirring conditions, with a stirring speed of 300~800 r / min and a time of 5~20 min; Step S1 also includes ultrasonic dispersion of the acidified system, with an ultrasonic power of 100~400W and a time of 10~30min.
3. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: The thioacetamide has a purity of over 98%; The mass ratio of material A to the metal chloride is (10~20):1; The mixing in step S2 is carried out under stirring conditions, with a stirring speed of 300~1000 r / min and a time of 30~60 min.
4. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: The liquid silicon source is one or more of silicon tetrachloride, methyl orthosilicate, ethyl orthosilicate, tetramethylcyclotetrasiloxane, and octamethylcyclotetrasiloxane. The mass ratio of material B to the liquid silicon source is (2~10):1; The mixing described in step S3 is carried out under stirring conditions, with a stirring speed of 500~1500 r / min and a time of 1~5 h; The inert gas is at least one of helium, argon, and nitrogen; The hydrothermal treatment temperature is 100~300℃, and the treatment time is 12~24h.
5. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: Step S3 also includes ball milling the hydrothermally treated system; The ball milling process is a high-energy ball milling process with a rotation speed of 1000~2000 r / min and a milling time of 12~24 h.
6. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: The drying process is freeze-drying; The freeze-drying time is 12~24h, and the drying temperature is -30~-50℃.
7. The method for preparing silicon-carbon anode material according to claim 1, characterized in that: The inert atmosphere is at least one of helium, argon, and nitrogen; The sintering temperature is 500~1000℃ and the time is 1~12h.
8. The silicon-carbon anode material obtained by the preparation method according to any one of claims 1-7.
9. A lithium-ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, characterized in that, The negative electrode comprises the silicon-carbon negative electrode material as described in claim 8.