High-dynamics silicon-carbon negative electrode material and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion battery electrode materials, particularly relates to a high-dynamics silicon-carbon negative electrode material and a preparation method thereof, and aims to solve the technical problems that a silicon-based negative electrode is remarkable in volume expansion and poor in conductivity, and single-walled carbon nanotubes are easy to agglomerate to cause uneven dispersion. The method comprises the following steps: forming a carbon coating layer on the surface of a silicon-based material through a chemical vapor deposition method, mediating single-walled carbon nanotubes by using a polymeric dispersant to form a stable dispersion liquid, mixing the carbon-coated silicon carbon material with the dispersion liquid to prepare slurry, and carrying out drying and optional calcination processes to prepare a target material. And uniform anchoring of the carbon nanotubes on the surfaces of the silicon-carbon particles is realized. The problem of agglomeration of the single-walled carbon nanotubes can be effectively solved, a continuous flexible three-dimensional conductive network is constructed, silicon particle exposure is avoided, volume strain is buffered, the conductivity of the material is improved, and the material is endowed with excellent capacity characteristics, rate capability and cycling stability.

Description

A high-kinetics silicon-carbon anode material and its preparation method Technical Field

[0001] This invention belongs to the field of lithium-ion battery electrode material technology, specifically relating to a high-kinetics silicon-carbon anode material and its preparation method. Background Technology

[0002] Lithium-ion batteries, with their advantages of high energy density, long cycle life, and low self-discharge rate, have become the most widely used rechargeable battery system. The theoretical specific capacity of traditional graphite anodes is only 378 mAh / g, while silicon-based anodes boast a theoretical specific capacity as high as 4200 mAh / g, significantly improving battery energy density and thus playing a crucial role in commercial high-capacity batteries. However, silicon undergoes approximately 360% volume expansion during lithium intercalation, easily leading to the pulverization of active material particles, continuous electrolyte consumption, and the continuous rupture and regeneration of the solid electrolyte interphase (SEI) film during cycling. Furthermore, silicon's inherently poor conductivity hinders rapid lithium-ion intercalation and deintercalation, limiting the battery's rate performance. These problems severely impede the commercialization of silicon-based anodes in lithium-ion batteries.

[0003] Currently, to address the issues of high expansion and low conductivity in silicon-based anode materials, the industry commonly employs chemical vapor deposition (CVD) to prepare carbon-coated silicon materials (i.e., silicon-carbon composites), which improves the initial efficiency and energy density of batteries to some extent. However, due to the often uneven carbon coating, some silicon particles remain exposed in the electrolyte, and the overall conductivity improvement is limited. Carbon nanotubes, due to their intrinsic sp2 covalent structure, possess excellent high conductivity, mechanical properties, and chemical stability, enabling them to bridge multiple active particles and construct a stable three-dimensional conductive network. Even if local structures shift due to expansion, electron transport paths remain unobstructed, thus making them ideal conductive agents for silicon-based anodes. Currently, adding carbon nanotubes and constructing carbon coatings have become one of the simplest and most effective strategies for improving the rate performance of silicon anodes, with single-walled carbon nanotubes emerging as a new development trend due to their superior performance. However, single-walled carbon nanotubes, due to their extremely strong van der Waals forces and large specific surface area, are prone to tangling and agglomeration; the drastic volume changes of silicon particles during cycling further exacerbate this agglomeration, making it difficult to disperse uniformly in the electrode. Therefore, developing a silicon-carbon anode material that can achieve uniform dispersion of single-walled carbon nanotubes and simultaneously possess high capacity, low expansion, high rate capability, and long cycle life is both challenging and of significant practical importance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-kinetics silicon-carbon anode material and its preparation method. The objective of this invention is to develop a silicon-carbon anode material capable of achieving uniform dispersion of single-walled carbon nanotubes while simultaneously possessing high capacity, low expansion, high rate capability, and long cycle life.

[0005] This invention addresses the dual challenges of carbon nanotubes' tendency to aggregate and their potential to cause uneven dispersion of silicon-carbon materials when used as additives. It employs a polymeric dispersant-mediated single-walled carbon nanotube dispersion strategy, combined with controlled feeding and dispersion processes, and specific drying and granulation techniques. This achieves uniform dispersion of carbon nanotubes followed by secondary coating of carbon-coated silicon nanoparticles. This allows the carbon nanotubes to be directly anchored to the silicon particle surface, inhibiting material aggregation. During repeated charge-discharge cycles, their high aspect ratio and mechanical strength enable the construction of a durable and stable conductive network and efficient buffering of volumetric stress.

[0006] The first aspect of this invention provides a method for preparing a high-kinetics silicon-carbon anode material, comprising the following steps: S1: forming a carbon coating layer on the surface of a silicon-based material using chemical vapor deposition to obtain a carbon-coated silicon-carbon material; S2: dissolving a polymeric dispersant in a solvent to form a dispersant solution; adding carbon nanotubes to the dispersant solution and dispersing them to obtain a carbon nanotube dispersion; S3: adding the carbon-coated silicon-carbon material prepared in step S1 to the carbon nanotube dispersion obtained in step S2 and stirring to form a mixed slurry; S4: removing the solvent from the mixed slurry obtained in step S3 and preparing it into powder to obtain the high-kinetics silicon-carbon anode material.

[0007] As a further optimization of the above preparation method, in the mixed slurry obtained in step S3, the mass of the polymeric dispersant is 0.05% to 0.4% of the mass of the carbon-coated silicon-carbon material, such as 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, or any range between the two; the mass of the single-walled carbon nanotubes is 0.02% to 0.08% of the mass of the carbon-coated silicon-carbon material, such as 0.02%, 0.04%, 0.06%, 0.08%, or any range between the two.

[0008] As a further optimization of any of the above preparation methods, in step S1, forming a carbon coating layer on the surface of a silicon-based material using chemical vapor deposition includes: loading a silicon-carbon precursor into a CVD reactor, introducing an inert gas to replace the air and establish an inert atmosphere, heating to 500±50℃ at 5±1℃ / min, introducing an acetylene / nitrogen mixture to maintain the temperature for 1±0.2 hours, turning off the acetylene / nitrogen gas after deposition, and allowing the nitrogen atmosphere to cool naturally to room temperature to obtain a carbon-coated silicon-carbon material.

[0009] As a further optimization of any of the above preparation methods, in step S2, the polymeric dispersant is selected from: polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium lignosulfonate.

[0010] As a further optimization of any of the above preparation methods, in step S2, the solvent is selected from: ethanol, a mixture of water and ethanol, and N-methylpyrrolidone.

[0011] As a further optimization of any of the above preparation methods, in step S2, the polymeric dispersant is dissolved in a solvent and ultrasonically treated for 8-15 minutes to completely dissolve the polymeric dispersant. Then, single-walled carbon nanotubes are added and ultrasonically dispersed for another 8-15 minutes to obtain a uniformly dispersed and stable carbon nanotube dispersion.

[0012] As a further optimization of any of the above preparation methods, in step S3, mechanical stirring, high-speed homogenization or ball milling is used to mix and form a mixed slurry, and the carbon nanotube dispersion is fully wetted and attached to the surface of the silicon carbon material.

[0013] As a further optimization of any of the above preparation methods, in step S4, the mixed slurry obtained in step S3 is transferred to a spray drying device and dried under an inert atmosphere. The inlet temperature of the spray dryer is controlled to be 100℃~300℃ and the outlet temperature is controlled to be 60℃~180℃. After drying, the powdered high-kinetic silicon-carbon anode material is obtained.

[0014] As a further optimization of any of the above preparation methods, in step S4, the mixed slurry obtained in step S3 is dried by forced air, ground and sieved to obtain powder, thus obtaining the high kinetic silicon-carbon anode material.

[0015] As a further optimization of the above preparation method, the powder obtained by drying, grinding and sieving the mixed slurry by forced air is placed in an atmosphere furnace for calcination. The calcination is carried out in an inert atmosphere, the calcination temperature is 400±50℃, the calcination time is 3±0.5h, and the high kinetic silicon-carbon anode material is obtained by cooling after calcination.

[0016] A second aspect of the present invention is to provide a high-kinetics silicon-carbon anode material, which is prepared by any of the above-described preparation methods.

[0017] Beneficial Effects: This invention first utilizes a polymeric dispersant for pretreatment to ensure sufficient dispersion of carbon nanotubes; then, it is rapidly mixed with silicon-carbon materials, and spray-dried to achieve uniform and robust coating of carbon nanotubes onto the surface of silicon-carbon particles. This method brings multiple significant effects: First, it achieves a high degree of uniform coating of nano-silicon, completely avoiding direct exposure of silicon particles; second, the carbon nanotubes in the coating layer form a continuous, flexible conductive network, which can both buffer huge volumetric strain, maintain the integrity of the electrode structure, and greatly improve the conductivity of the composite material. The synergistic effect of these two factors ultimately significantly improves the cycle stability and overall electrochemical performance of lithium-ion batteries. Attached Figure Description

[0018] Figure 1 is a SEM image of the silicon-carbon anode material prepared in Example 1 of the present invention.

[0019] Figure 2 is a SEM image of the silicon-carbon anode material prepared in Example 2 of the present invention.

[0020] Figure 3 is a SEM image of the silicon-carbon anode material prepared in Example 3 of the present invention.

[0021] Figure 4 is a SEM image of the silicon-carbon anode material prepared in Example 4 of the present invention.

[0022] Figure 5 shows the SEM image of the silicon-carbon anode material prepared in Comparative Example 1.

[0023] Figure 6 shows the SEM image of the silicon-carbon anode material prepared in Comparative Example 2. Detailed Implementation

[0024] The present invention is further illustrated below with specific embodiments. These embodiments are exemplary and intended to illustrate the problem and explain the present invention, and are not intended to be limiting.

[0025] Example 1 The preparation of silicon-carbon anode material in this example includes the following steps: (1) Amorphous carbon layer is coated on the surface of nano-silicon particles by chemical vapor deposition to obtain carbon-coated silicon-carbon material.

[0026] (2) Polyvinylpyrrolidone (PVP) was added to anhydrous ethanol, and the mass ratio of PVP to silicon carbon material was 0.1%, 0.2%, 0.3%, and 0.4%, respectively. The mixture was ultrasonically treated for 10 min to dissolve it completely. Then, single-walled carbon nanotubes were added at a mass ratio of 0.02%, 0.04%, 0.06%, and 0.08% of the silicon carbon material, respectively. The mixture was ultrasonically dispersed for another 10 min to obtain a uniform and stable carbon nanotube dispersion.

[0027] (3) To achieve uniform loading of carbon nanotubes on the surface of silicon carbon material, a composite operation is carried out: First, carbon-coated silicon carbon material is added to the dispersion liquid, and the material is fully wetted and initially dispersed by stirring with a glass rod to prevent agglomeration caused by direct high-speed stirring; then, it is mechanically stirred at a speed of 800 r / min for 1 hour. During this process, the continuous shear force ensures that the carbon nanotube dispersion liquid and the surface of silicon carbon material are fully and uniformly contacted and composited, thereby forming a stable mixed slurry.

[0028] (4) Transfer the mixed slurry obtained in step (3) to a spray dryer and dry it under a nitrogen atmosphere. Control the inlet temperature of the spray dryer to 120°C and the outlet temperature to 100°C. After drying is completed, collect the black powdered composite material in a collection device.

[0029] Example 2 The preparation of silicon-carbon anode material in this example includes the following steps: (1) Amorphous carbon layer is coated on the surface of nano-silicon particles by chemical vapor deposition to obtain carbon-coated silicon-carbon material.

[0030] (2) Add the carbon-coated silicon carbon material obtained in step (1) into anhydrous ethanol and sonicate it for 10 min to fully disperse it in the solvent and form a uniform silicon carbon material-ethanol dispersion.

[0031] (3) Sodium dodecylbenzenesulfonate (SDBS) dispersant was added to deionized water. The mass ratio of SDBS to silicon carbon material was 0.1%, 0.2%, 0.3%, and 0.4%, respectively. The corresponding mass of SDBS was weighed and ultrasonically treated for 20 min to dissolve it completely. Then, single-walled carbon nanotubes were added at a mass ratio of 0.04% and 0.08% of the silicon carbon material, respectively, and ultrasonically dispersed for another 10 min to obtain a series of carbon nanotube aqueous dispersions with different ratios, uniform dispersion and stability.

[0032] (4) The carbon nanotube dispersions prepared in step (3) are slowly added to the silicon carbon material-ethanol dispersion in step (2); the mixture is placed on a mechanical stirrer and stirred continuously at a speed of 800 r / min for 2 hours; during this process, the continuous shear force ensures that the carbon nanotubes and silicon carbon material surfaces are fully and uniformly contacted and combined, and finally multiple stable mixed slurries are formed.

[0033] (5) Transfer the mixed slurries obtained in step (4) to petri dishes, place them in a forced-air drying oven, and dry them at 120°C for 12 hours to completely remove moisture and ethanol solvent; after drying, grind and sieve to collect black powder, thus obtaining a series of single-walled carbon nanotube coated silicon carbon composite materials under different process parameters.

[0034] Example 3 The preparation of silicon-carbon anode material in this example includes the following steps: (1) Amorphous carbon layer is coated on the surface of nano-silicon particles by chemical vapor deposition to obtain carbon-coated silicon-carbon material.

[0035] (2) Weigh 0.2 g of sodium lignosulfonate, add it to 20 g of deionized water, and sonicate it for 10 min to dissolve it completely, thus obtaining an aqueous solution of sodium lignosulfonate.

[0036] (3) The amount of single-walled carbon nanotubes (aqueous) added is fixed at 0.08% of the mass of silicon carbon material; different masses of sodium lignosulfonate aqueous solution prepared in step (2) are weighed, and the mass ratio of sodium lignosulfonate to silicon carbon material is 0.05%, 0.1%, 0.2%, and 0.4%, respectively; the corresponding mass of single-walled carbon nanotubes is added to each lignin aqueous solution, and ultrasonic dispersion is continued for 10 min, thereby preparing a series of carbon nanotube dispersions with different dispersant contents.

[0037] (4) Add the carbon-coated silicon carbon material obtained in step (1) into anhydrous ethanol and sonicate for 10 min to fully disperse it and form a uniform silicon carbon material-ethanol dispersion.

[0038] (5) The carbon nanotube dispersion prepared in step (3) is slowly added to the silicon carbon material-ethanol dispersion in step (4); the mixture is placed on a mechanical stirrer and stirred continuously at a speed of 800 r / min for 2 hours; finally, multiple stable mixed slurries are formed.

[0039] (6) The mixed slurries obtained in step (5) are dried by blowing at 120°C for 12 hours, ground and sieved, and then placed in an atmosphere furnace and calcined at 400°C for 3 hours under an inert atmosphere of Ar to obtain a series of composite materials with different process parameters.

[0040] Example 4 The preparation of silicon-carbon anode material in this example includes the following steps: (1) Amorphous carbon layer is coated on the surface of nano-silicon particles by chemical vapor deposition to obtain carbon-coated silicon-carbon material.

[0041] (2) Add the carbon-coated silicon carbon material obtained in step (1) into N-methylpyrrolidone solvent, wherein the mass ratio of N-methylpyrrolidone to silicon carbon material is 2:1, and sonicate for 10 min to fully disperse it and form a uniform silicon carbon material dispersion.

[0042] (3) Weigh out single-walled carbon nanotubes (NMP) at proportions of 0.02%, 0.04%, 0.06%, and 0.08% of the mass of silicon-carbon material, respectively, and add them to the silicon-carbon dispersion obtained in step (2). First, pre-disperse the mixture by stirring with a glass rod, and then mechanically stir it at a speed of 800 r / min for 2 h to form a stable mixed slurry.

[0043] (4) The mixed slurry obtained in step (3) is transferred to a spray drying device and spray dried under nitrogen atmosphere protection. The inlet temperature is controlled at 200°C and the outlet temperature is controlled at 120°C. After drying, black powdered silicon-carbon composite material is collected.

[0044] Comparative Example 1: The silicon-carbon anode material in this comparative example uses only carbon-coated silicon-carbon material, without carbon nanotube coating.

[0045] Comparative Example 2 The preparation of the silicon-carbon anode material in the comparative example includes the following steps: (1) Weigh out the corresponding mass of single-walled carbon nanotubes according to the proportion of single-walled carbon nanotubes to silicon-carbon materials in the final composite product of 0.08%, and add them to twice the mass of deionized water. Ultrasonically treat at 75% rated power for 20 min to obtain a uniformly dispersed and stable aqueous dispersion of single-walled carbon nanotubes.

[0046] (2) Accurately weigh 25 g of carbon-coated silicon carbide material and place it in a beaker; add anhydrous ethanol according to the mass ratio of silicon carbide material to anhydrous ethanol of 1:2, and stir initially with a glass rod to fully wet and disperse the silicon carbide material in the ethanol to form a silicon carbide-ethanol suspension.

[0047] (3) Slowly pour all the carbon nanotube dispersion prepared in step (1) into the silicon carbon-ethanol suspension in step (2); place the mixture on a mechanical stirrer and stir continuously at a speed of 800 r / min for 2 h to make the carbon nanotubes and silicon carbon materials fully and uniformly composite.

[0048] (4) Transfer the homogeneous mixture obtained in step (3) to a desiccator and place it in a forced-air drying oven at 120°C for 12 h to completely remove the water and ethanol solvent.

[0049] (5) The solid block material that has been naturally cooled to room temperature is crushed using a mortar and pestle and then sieved through a standard sieve to collect black powder with a particle size of 200 mesh or larger, thus obtaining a single-walled carbon nanotube coated silicon carbon composite material.

[0050] Preparation of Carbon-Coated Silicon-Carbon Materials: In the above examples and comparative examples, carbon-coated silicon-carbon materials were prepared by chemical vapor deposition (CVD) to coat an amorphous carbon layer onto the surface of nano-silicon particles. Specifically, porous carbon materials were loaded into a fluidized bed, using silane (SiH4) as the silicon source. Nitrogen was introduced to replace air, establishing an inert atmosphere. The current ratio (N2:SiH4) was 1:2, and the temperature was increased to 500°C at 5°C / min and held for 2 hours. An acetylene / nitrogen mixture was then introduced, with a current ratio (acetylene:N2) of 1:4, and the temperature was increased to 600°C at 5°C / min and held for 1 hour to allow carbon atoms to be uniformly deposited on the material surface. After deposition, the acetylene / nitrogen gas was turned off, maintaining a nitrogen atmosphere, and the material was allowed to cool naturally to room temperature before being removed.

[0051] Performance testing (1) The physicochemical properties of the silicon-carbon anode materials prepared in Examples 1-4 and Comparative Examples 1-2 of this invention were characterized by SEM images. It was found that the 0.1wt% PVP and 0.08wt% single-walled carbon nanotube experimental group in Example 1, the 0.1wt% SDBS and 0.04wt% single-walled carbon nanotube experimental group in Example 2, the 0.1wt% sodium lignosulfonate experimental group in Example 3, and the 0.02wt% single-walled carbon nanotube experimental group in Example 4 had excellent dispersion effects. The test results are shown in Table 1.

[0052] Table 1 The testing methods are as follows: ①SEM: The morphology of key materials is analyzed using scanning electron microscopy.

[0053] ② Specific surface area: Tested using a fully automated specific surface area analyzer.

[0054] ③ Electrical conductivity: Tested using a powder conductivity and resistance meter. 1g of sample was weighed and placed in a mold, and the powder conductivity was obtained at 200mPa by applying pressure.

[0055] ④ Particle size: Tested using a laser particle size analyzer.

[0056] (2) The silicon-carbon anode materials prepared in Examples 1-4 and Comparative Examples 1-2 of this invention were used as active materials. They were mixed in a mass ratio of 8:1:1 (active material, conductive agent (Super P), and binder (PAA), and deionized water solvent was added. The mixture was thoroughly stirred to form a uniform anode slurry. This slurry was uniformly coated onto a copper foil current collector, dried, rolled, and then punched into a 14mm diameter disc to obtain the anode sheet. In a glove box protected by an argon atmosphere, a lithium metal sheet was used as the counter electrode, KLD-SiO1 was used as the electrolyte, and Celgard 2500 was used as the separator. The resulting CR2016 coin cell was then assembled for subsequent electrochemical performance testing. In Example 1, the silicon-carbon anode material used in the test was a sample containing 0.1 wt% PVP and 0.08 wt% single-walled carbon nanotubes; in Example 2, the silicon-carbon anode material used in the test was a sample containing 0.1 wt% SDBS and 0.04 wt% single-walled carbon nanotubes; in Example 3, the silicon-carbon anode material used in the test was a sample containing 0.1 wt% sodium lignosulfonate as silicon-carbon material; and in Example 4, the silicon-carbon anode material used in the test was a sample containing 0.02 wt% single-walled carbon nanotubes. The test results are shown in Table 2.

[0057] Table 2 As shown in Table 1, the silicon-carbon anode materials prepared in Examples 1-4 of this invention all exhibit excellent electrochemical performance. Their discharge capacity at 1.5V remains above 1800 mAh / g, with an initial efficiency exceeding 92%. Under 5C high-rate charge-discharge conditions, they not only possess high discharge capacity but also maintain a capacity retention rate above 95%. Even after five 5C cycles, the capacity retention rate remains stable at around 92%, indicating excellent rate performance and cycle stability. Comparative Example 1 did not undergo carbon nanotube coating treatment; it only used basic carbon-coated silicon-carbon material. In terms of performance, Comparative Example 1 has a similar capacity at 1.5V to Example 1, but its capacity retention rate after 5C cycles is only 89.9%, significantly lower than the 92.7% of Example 1. Comparative Example 2 did not use a polymeric dispersant; carbon nanotubes were dispersed only through ultrasonic treatment and then combined with silicon-carbon materials. In terms of performance, the capacity retention rate of Comparative Example 2 after 5C cycling was 91.9%, which was slightly lower than that of Example 2 (92.3%).

[0058] Figures 1 and 2 show SEM images of the silicon-carbon anode materials prepared in Examples 1 and 2, respectively, while Figures 3 and 4 show SEM images of the silicon-carbon anode materials prepared in Comparative Examples 1 and 2, respectively. The SEM image of Comparative Example 1 shows a uniformly dispersed silicon-carbon material morphology; the SEM image of Comparative Example 2 shows that after adding single-walled carbon nanotubes, the carbon nanotubes form obvious aggregates or entanglements, resulting in poor dispersion and agglomeration of the silicon-carbon material; the SEM image of Example 2 shows that after adding a polymeric dispersant, the agglomeration problem is effectively improved, but a small amount of agglomeration can still be observed; the SEM image of Example 1 shows that both single-walled carbon nanotubes and silicon-carbon material are well dispersed, and the aforementioned aggregation and agglomeration problems are significantly improved. In particular, in Example 1, polyvinylpyrrolidone (PVP) was used as a dispersant, effectively overcoming the technical difficulties of easy agglomeration of single-walled carbon nanotubes and uneven dispersion of silicon-carbon material during addition, and constructing a continuous and stable three-dimensional conductive network on the surface of silicon-carbon particles. This structure not only significantly buffers the volume change of the active material, but also effectively improves the transport efficiency of lithium ions and electrons, thereby comprehensively optimizing its overall electrochemical performance.

[0059] In summary, this invention effectively solves the problem of single-walled carbon nanotubes' tendency to agglomerate in the system by pretreating them with a polymeric dispersant, ensuring their full and uniform dispersion. Subsequently, the well-dispersed carbon nanotubes are rapidly mixed with silicon-carbon materials, and finally, a spray-drying process is used to achieve a uniform and firm coating of single-walled carbon nanotubes on the surface of silicon-carbon particles. This method, through effective physical composite and structural modification of the silicon-carbon anode material, significantly alleviates its volume expansion during charge and discharge processes and greatly improves the material's cycle stability and rate performance, providing a reliable technical path for the large-scale preparation of high-performance silicon-carbon anode materials.

[0060] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-kinetics silicon-carbon anode material, characterized in that, Includes the following steps: S1: A carbon coating layer is formed on the surface of a silicon-based material using chemical vapor deposition to obtain a carbon-coated silicon-carbon material; S2: A polymeric dispersant is dissolved in a solvent to form a dispersant solution; carbon nanotubes are added to the dispersant solution and dispersed to obtain a carbon nanotube dispersion; S3: The carbon-coated silicon-carbon material prepared in step S1 is added to the carbon nanotube dispersion obtained in step S2, and the mixture is stirred to form a mixed slurry; S4: Remove the solvent from the mixed slurry obtained in step S3 and make it into powder to obtain the high kinetic silicon-carbon anode material; in the mixed slurry obtained in step S3, the mass of the polymeric dispersant is 0.05%~0.4% of the mass of the carbon-coated silicon-carbon material, and the mass of the single-walled carbon nanotube is 0.02%~0.08% of the mass of the carbon-coated silicon-carbon material.

2. The preparation method according to claim 1, characterized in that, In step S1, forming a carbon coating layer on the surface of a silicon-based material using chemical vapor deposition includes: loading a silicon-carbon precursor into a CVD reactor, introducing an inert gas to replace the air and establish an inert atmosphere, heating to 500±50℃ at 5±1℃ / min, introducing an acetylene / nitrogen mixture to maintain the temperature for 1±0.2 hours, turning off the acetylene / nitrogen gas after deposition, and allowing the nitrogen atmosphere to cool naturally to room temperature to obtain a carbon-coated silicon-carbon material.

3. The preparation method according to claim 1, characterized in that, In step S2, the polymeric dispersant is selected from: polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and sodium lignosulfonate.

4. The preparation method according to claim 3, characterized in that, In step S2, the solvent is selected from: ethanol, a mixture of water and ethanol, and N-methylpyrrolidone.

5. The preparation method according to claim 4, characterized in that, In step S2, the polymeric dispersant is dissolved in a solvent and ultrasonically treated for 8–15 min to completely dissolve the polymeric dispersant. Then, single-walled carbon nanotubes are added and ultrasonically dispersed for another 8–15 min to obtain a uniformly dispersed and stable carbon nanotube dispersion.

6. The preparation method according to claim 1, characterized in that, In step S3, a mixed slurry is formed by mechanical stirring, high-speed homogenization or ball milling, and the carbon nanotube dispersion is fully wetted and adhered to the surface of the silicon carbon material.

7. The preparation method according to claim 1, characterized in that, In step S4, the mixed slurry obtained in step S3 is transferred to a spray drying device and dried under an inert atmosphere. The inlet temperature of the spray dryer is controlled to be 100℃~300℃ and the outlet temperature is controlled to be 60℃~180℃. After drying, the powdered high-kinetic silicon-carbon anode material is obtained.

8. The preparation method according to claim 1, characterized in that, In step S4, the mixed slurry obtained in step S3 is dried by forced air, ground and sieved to obtain powder, which is the high kinetic silicon-carbon anode material.

9. The preparation method according to claim 8, characterized in that, The method also includes placing the powder obtained by drying, grinding and sieving the mixed slurry in an atmosphere furnace for calcination. The calcination is carried out in an inert atmosphere at a temperature of 400±50℃ for 3±0.5h. After calcination, the powder is cooled to obtain the high-kinetic silicon-carbon anode material.

10. A high-kinetics silicon-carbon anode material, characterized in that, Prepared by the method according to any one of claims 1-9.

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