A high-performance lithium battery anode material and its preparation method

Abstract

The present invention discloses a high-performance lithium battery negative electrode material and a preparation method thereof, belonging to the technical field of batteries and battery materials. The high-performance lithium battery negative electrode material is prepared by mixing modified silicon powder and Ce-Zn nanocomposite materials by ball milling to obtain a mixed substrate. The Ce-Zn nanocomposite materials are fully dispersed on the surface of the nano-silicon powder by the dual effects of mechanical pressing and electrical adsorption. At the same time, the modified nano-silicon powder is coated and co-pyrolyzed using a dopamine hydrochloride coating and modification method to obtain a nitrogen-doped carbon-silicon composite electrode material. The electrode material has good electrical conductivity and cyclic stability, effectively alleviating the pulverization effect caused by the volume expansion of nano-silicon, while combining high initial coulombic efficiency with good cyclic stability.

Description

Technical Field

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

[0002] With the rapid development of electric vehicles, wearable devices, and renewable energy storage, higher demands are being placed on the energy density, cycle life, and safety of lithium-ion batteries. The negative electrode material is one of the key components of a lithium battery, directly determining its cycle life and capacity.

[0003] There are many types of anode materials in lithium-ion batteries. Based on their chemical properties and composition, they can be mainly divided into two categories: carbon-based materials and non-carbon-based materials. Carbon-based materials are the most widely used anode materials in lithium-ion batteries, mainly including natural graphite, artificial graphite, mesophase carbon microspheres, soft carbon, and hard carbon. Non-carbon-based materials mainly include silicon-based materials, titanium-based materials, tin-based materials, and metallic lithium. These materials have unique advantages in terms of energy density and cycle stability, but they also face some challenges. Carbon-based materials have become one of the most widely used anode materials in the commercial market due to their good safety performance, excellent cycle performance, and high energy density. Although carbon materials have good electrochemical stability and a low lithium intercalation potential, their theoretical capacity is limited, making it difficult to meet the ever-increasing demand for high energy density. Silicon has an extremely high theoretical specific capacity (approximately 4200 mAh / g), far exceeding that of traditional graphite anode materials (approximately 372 mAh / g). However, silicon suffers from severe volume expansion during charge and discharge, which can lead to pulverization and shedding of the electrode material, thus affecting the battery's cycle performance. Therefore, the preparation of lithium-ion battery anode materials with better performance has become a research focus in related fields. Summary of the Invention

[0004] The purpose of this invention is to provide a high-performance lithium battery anode material and its preparation method. The electrode material, by adding Ce-Zn composite nanomaterials, can co-build a stable conductive network with nano-silicon powder and carbon, thereby improving the overall conductivity of the carbon-silicon composite electrode material, which is beneficial to electron transport and thus enhances the electrochemical performance of the electrode.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0007] (1) 0.1g of 3-aminopropyltriethoxysilane was added to 50ml of ethanol-water mixture and stirred to dissolve for 15min. Then 4g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45min, the temperature was raised to 50℃ and stirred to react for 2h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder.

[0008] (2) The modified nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:(0.1-0.3) and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0009] (3) The mixed substrate is dispersed in a Tris solution of dopamine according to a certain ratio, and after standing for 15-20 min, it is stirred and mixed for 20 h. The reaction product is washed by centrifugation with deionized water multiple times, and then placed in an oven to dry. The dried sample is then placed in a tube furnace, nitrogen is introduced, the heating rate is controlled at 5℃ / min, and the temperature is raised to 800℃ and kept for 2 h to obtain the high-performance lithium battery anode material.

[0010] Furthermore, in step (1), the volume ratio of anhydrous ethanol to water in the ethanol-water mixed solution is 99:1; and the particle size of the nano-silicon powder is 80-100nm.

[0011] Furthermore, in step (3), the mass concentration of the dopamine Tris solution is 4 mg / mL and the pH is 8.9.

[0012] Furthermore, in step (3), the ratio of the mixed substrate to the dopamine Tris solution is 100 mg: 50 ml.

[0013] Furthermore, the Ce-Zn nanocomposite material in step (2) is prepared using the following method:

[0014] a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution;

[0015] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to separate the precipitate, wash it three times with deionized water and anhydrous ethanol, and then dry it in an oven.

[0016] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

[0017] Preferably, in step a), the volume ratio of anhydrous ethanol to deionized water in the ethanol-water solution is 1:1.

[0018] Preferably, the high-temperature reaction temperature in step b) is 150°C.

[0019] Preferably, in step b), the oven drying temperature is 60°C and the drying time is 12 hours.

[0020] A high-performance lithium battery anode material prepared by the above method is used as follows: The anode material prepared by this invention is thoroughly ground and then ground and stirred with conductive black and binder at a mass ratio of 8:1:1 until a uniformly dispersed slurry is formed. This slurry is then coated onto copper foil using an I-shaped scraper, with a slurry thickness of 75 μm. After drying in a vacuum drying oven at 60°C for 12 hours, it is removed and cut into 12 mm diameter discs using a slicing machine and pressed into sheets at a pressure of 6 MPa to obtain the lithium battery anode sheet.

[0021] Silicon, abundant in the Earth's crust, possesses a high theoretical specific capacity (4200 mA·h / g) and a low lithium insertion potential. However, directly using it as a negative electrode material does not demonstrate its high capacity advantage. This is mainly because the insertion / extraction of lithium ions into / out of silicon cells causes severe volume expansion, leading to cracks on the electrode surface and resulting in rapid capacity decay and poor cycle life. Combining nano-silicon with carbon materials (such as graphene and graphylene) to alleviate the volume effect of silicon and ensure the integrity of the SEI film is an effective method to improve electrode capacity and increase the first coulombic efficiency. This invention utilizes 3-aminopropyltriethoxysilane to modify nano-silicon powder, giving the surface a charge. Ce-Zn composite metal nanoparticles are then adsorbed onto the nano-silicon surface via electroadsorption. Simultaneously, the modified nano-silicon powder and Ce-Zn nanocomposite material are mechanically ball-milled. Mechanical stress pressing stabilizes the Ce-Zn composite metal nanoparticles on the nano-silicon powder surface, forming a mixed substrate. Finally, a carbonization heat treatment under a nitrogen atmosphere is performed, thereby establishing a stable conductive network composed of Ce-Zn composite metal nanoparticles, nano-silicon powder, and carbon. This improves the overall conductivity of the carbon-silicon composite electrode material, facilitating electron transport and enhancing the electrochemical performance of the electrode material. The introduction of a nitrogen-doped carbon layer improves the conductivity and cycle performance of silicon-based materials, while the addition of Ce-Zn nanocomposite material alleviates silicon volume expansion, maintains the structural stability of the electrode material, and further increases the specific surface area, providing more active sites and facilitating lithium ion insertion and extraction, thus improving the electrode's specific capacity.

[0022] The beneficial effects of the present invention are as follows: the lithium battery anode material prepared by the present invention can effectively reduce the volume expansion of silicon material, which is conducive to the insertion and extraction of lithium ions, and has high specific capacity, good conductivity and cycle performance. The preparation method is simple and easy to operate, and has extremely high market application and promotion value. Attached Figure Description

[0023] Figure 1 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the negative electrode material obtained in Example 3 of the present invention, where a) is a scanning electron microscope image, and b) and c) are TEM images. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to specific embodiments, but it is not limited thereto.

[0025] Example 1

[0026] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0027] (1) 0.1 g of 3-aminopropyltriethoxysilane was added to 50 ml of a mixed solution of ethanol and water and stirred to dissolve for 15 min. Then, 4 g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45 min, the temperature was raised to 50 °C and stirred to react for 2 h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. The volume ratio of anhydrous ethanol to water in the ethanol-water mixed solution was 99:1. The particle size of the nano-silicon powder was 80 nm.

[0028] (2) The modified nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:0.1 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0029] (3) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0030] The Ce-Zn nanocomposite material was prepared using the following method:

[0031] a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0032] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0033] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

[0034] Example 2

[0035] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0036] (1) 0.1 g of 3-aminopropyltriethoxysilane was added to 50 ml of a mixed solution of ethanol and water and stirred to dissolve for 15 min. Then, 4 g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45 min, the temperature was raised to 50 °C and stirred to react for 2 h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. The volume ratio of anhydrous ethanol to water in the ethanol-water mixed solution was 99:1. The particle size of the nano-silicon powder was 90 nm.

[0037] (2) The modified nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:0.2 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0038] (3) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0039] The Ce-Zn nanocomposite material was prepared using the following method:

[0040] a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0041] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0042] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

[0043] Example 3

[0044] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0045] (1) 0.1 g of 3-aminopropyltriethoxysilane was added to 50 ml of a mixed solution of ethanol and water and stirred to dissolve for 15 min. Then, 4 g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45 min, the temperature was raised to 50 °C and stirred to react for 2 h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. The volume ratio of anhydrous ethanol to water in the mixed solution of ethanol and water was 99:1. The particle size of the nano-silicon powder was 100 nm.

[0046] (2) The modified nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:0.3 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0047] (3) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0048] The Ce-Zn nanocomposite material was prepared using the following method:

[0049] a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0050] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0051] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

[0052] Comparative Example 1

[0053] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0054] (1) The nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:0.3 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0055] (2) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0056] The Ce-Zn nanocomposite material was prepared using the following method:

[0057] a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0058] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0059] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

[0060] The raw materials and preparation methods of this comparative high-performance lithium battery anode material are basically the same as those in Example 3, the only difference being that the nano-silicon powder was not modified.

[0061] Comparative Example 2

[0062] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0063] (1) 0.1 g of 3-aminopropyltriethoxysilane was added to 50 ml of a mixed solution of ethanol and water and stirred to dissolve for 15 min. Then, 4 g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45 min, the temperature was raised to 50 °C and stirred to react for 2 h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. The volume ratio of anhydrous ethanol to water in the mixed solution of ethanol and water was 99:1. The particle size of the nano-silicon powder was 100 nm.

[0064] (2) The modified nano-silicon powder and Ce nanomaterial were mixed at a mass ratio of 1:0.3 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0065] (3) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0066] The Ce nanomaterial was prepared using the following method:

[0067] a) Dissolve 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0068] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0069] c) The dried product was placed in a muffle furnace and calcined at 600°C for 2 hours to obtain Ce nanomaterials.

[0070] The raw materials and preparation methods of this comparative high-performance lithium battery anode material are basically the same as those in Example 3. The only difference is that the Ce-Zn nanocomposite material is only Ce nanomaterial.

[0071] Comparative Example 3

[0072] A method for preparing a high-performance lithium battery anode material includes the following steps:

[0073] (1) 0.1 g of 3-aminopropyltriethoxysilane was added to 50 ml of a mixed solution of ethanol and water and stirred to dissolve for 15 min. Then, 4 g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45 min, the temperature was raised to 50 °C and stirred to react for 2 h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. The volume ratio of anhydrous ethanol to water in the mixed solution of ethanol and water was 99:1. The particle size of the nano-silicon powder was 100 nm.

[0074] (2) The modified nano-silicon powder and Zn nanocomposite material were mixed at a mass ratio of 1:0.3 and placed in a ball milling jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate.

[0075] (3) The mixed substrate and the Tris solution of dopamine were mixed evenly at a ratio of 100mg:50ml. After standing for 15-20min, the mixture was stirred for 20h. The reaction product was washed by centrifugation with deionized water several times and then dried in an oven. The dried sample was then placed in a tube furnace, nitrogen gas was introduced, and the heating rate was controlled at 5℃ / min. After the temperature reached 800℃, it was kept at that temperature for 2h to obtain the high-performance lithium battery anode material. The mass concentration of the dopamine Tris solution was 4mg / mL and the pH was 8.9.

[0076] The Ce-Zn nanocomposite material was prepared using the following method:

[0077] a) Dissolve 3.3g Zn(CH3COO)3·2H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1;

[0078] b) Transfer the mixture to a high-pressure reactor and react at high temperature for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to obtain the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven at 60°C for 12 hours; the high-temperature reaction temperature is 150°C.

[0079] c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Zn nanomaterials.

[0080] The raw materials and preparation methods of this comparative high-performance lithium battery anode material are basically the same as those in Example 3. The only difference is that the Ce-Zn nanocomposite material is only a Zn nanomaterial.

[0081] Performance testing

[0082] The negative electrode material prepared in this invention was thoroughly ground and then ground and stirred with acetylene black and sodium alginate at a mass ratio of 8:1:1 until a uniformly dispersed slurry was formed. This slurry was then coated onto copper foil using an I-shaped scraper, with a thickness of 75 μm. It was dried in a vacuum drying oven at 60°C for 12 hours, then cut into 12 mm diameter discs using a slicer and pressed at a pressure of 6 MPa to obtain the lithium battery negative electrode sheet. After weighing and marking, it was quickly transferred to an argon atmosphere glove box for assembly into a CR-2032 coin cell. The counter electrode was a lithium metal sheet, and the separator was Celgard 2400 with a diameter of 19 mm. After assembly and standing for 12 hours, various electrochemical performance tests were performed. Cyclic charge-discharge tests were conducted using a battery charge-discharge testing system at a set current density, with a voltage range of 0.01–2.00 V. First, it was activated for 3 cycles at a current density of 50 mA / g, and then subjected to a long-cycle test at a current density of 100 mA / g. The specific test results are shown in Table 1.

[0083] Table 1 Performance Test Results

[0084]

[0085] As can be seen from the above data, the high-performance lithium battery anode material prepared by this invention has good electrochemical performance, with high discharge specific capacity, good conductivity and cycle performance. This indicates that the mixed substrate behind the metal Ce-Zn nanocomposite material and modified nano-silicon powder, after being coated with nitrogen-doped carbon, and with the combined effect of multiple different element doping, the good interface formed between the nanomaterial and the carbon-silicon matrix promotes the transport and diffusion of lithium ions, reduces the interface resistance, and improves the cycle stability and rate performance of the electrode. On the other hand, it also promotes the formation of a stable SEI film on the material surface, thereby greatly improving the electrochemical performance of the material.

[0086] It should be noted that the above embodiments are merely some preferred embodiments of the present invention, and not all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance lithium battery anode material, characterized in that, It includes the following steps: (1) 0.1g of 3-aminopropyltriethoxysilane was added to 50ml of ethanol-water mixture and stirred to dissolve for 15min. Then 4g of nano-silicon powder was added and stirred to mix evenly. After ultrasonic dispersion for 45min, the temperature was raised to 50℃ and stirred to react for 2h. The resulting reactant was dried under vacuum to obtain modified nano-silicon powder. (2) The modified nano-silicon powder and Ce-Zn nanocomposite material were mixed at a mass ratio of 1:(0.1-0.3) and placed in a ball mill jar filled with inert gas for mixing and ball milling. The ball milling speed was 500 r / min and the ball milling time was 10-12 h to obtain the mixed substrate. (3) The mixed substrate is dispersed in a Tris solution of dopamine according to a certain ratio, and after standing for 15-20 min, it is stirred and mixed for 20 h. The reaction product is washed by centrifugation with deionized water multiple times, and then placed in an oven to dry. The dried sample is then placed in a tube furnace, nitrogen is introduced, the heating rate is controlled at 5℃ / min, and the temperature is raised to 800℃ and kept for 2 h to obtain the high-performance lithium battery anode material. The Ce-Zn nanocomposite material in step (2) is prepared by the following method: a) Dissolve 3.3g Zn(CH3COO)3·2H2O, 0.33g Ce(NO3)3·6H2O and 1.4g NaOH in 50mL of ethanol aqueous solution, and stir magnetically at 40℃ for 1h to obtain a mixed solution; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 1:1; b) Transfer the mixture to a high-pressure reactor and react at 150°C for 4 hours. After the reaction is complete, cool to room temperature, centrifuge to separate the precipitate, wash it three times with deionized water and anhydrous ethanol, and then place it in an oven to dry at 60°C for 12 hours. c) The dried product was placed in a muffle furnace and calcined at 600℃ for 2 hours to obtain Ce-Zn nanocomposite material.

2. The method for preparing the high-performance lithium battery anode material according to claim 1, characterized in that, In step (1), the volume ratio of anhydrous ethanol to water in the ethanol-water mixture is 99:1; the particle size of the nano-silicon powder is 80-100nm.

3. The method for preparing the high-performance lithium battery anode material according to claim 1, characterized in that, In step (3), the dopamine Tris solution has a mass concentration of 4 mg / mL and a pH of 8.

9.

4. The method for preparing the high-performance lithium battery anode material according to claim 1, characterized in that, In step (3), the ratio of the mixed substrate to the dopamine Tris solution is 100 mg: 50 ml.

5. A lithium battery anode material prepared by the method for preparing a high-performance lithium battery anode material according to any one of claims 1-4.

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