WO2022121136A1

WO2022121136A1 - Artificial graphite negative electrode material for high-rate lithium ion battery and preparation method therefor

Info

Publication number: WO2022121136A1
Application number: PCT/CN2021/080150
Authority: WO
Inventors: 葛传长; 仰永军
Original assignee: 广东凯金新能源科技股份有限公司
Priority date: 2020-12-10
Filing date: 2021-03-11
Publication date: 2022-06-16
Also published as: CN112573923A

Abstract

Disclosed are an artificial graphite negative electrode material for a high-rate lithium ion battery and a preparation method therefor. The artificial graphite negative electrode material uses coke which is easily graphitized as a raw material, and is prepared by means of the steps of crushing, chemical etching and shaping, surface oxidation treatment, oxidation modification, coating, carbonization, compound granulation, graphitization, demagnetization and screening, etc. The relatively high energy density and good processing performance of the material are ensured while also improving the quick charging performance.

Description

A kind of high rate lithium ion battery artificial graphite negative electrode material and preparation method thereof

CROSS-REFERENCE TO RELATED APPLICATIONS.

This application claims the priority of the Chinese patent application filed on December 10, 2020, with the application number of 202011434666.X and the invention titled "A high-rate lithium-ion battery artificial graphite anode material and its preparation method", The entire contents of which are incorporated herein by reference.

technical field

The invention relates to the field of graphite negative electrode materials, in particular to an artificial graphite negative electrode material for high-rate lithium ion batteries and a preparation method thereof.

Background technique

Lithium-ion batteries have excellent properties such as high energy density, high operating voltage, small size, rapid charge and discharge, and long cycle life. The power supply for hybrid electric vehicles (HEV), and the development of smart grids and energy storage power stations are also inseparable from high-performance lithium-ion batteries. The rapid development of the electronic information industry and electric vehicles has greatly affected the energy density and power density of next-generation lithium-ion batteries And the longevity puts forward higher requirements.

technical problem

At present, lithium-ion batteries mainly use graphite-based materials as anode materials. Traditional graphite-based anode materials have problems such as poor cycling and poor rate performance during their cycling process. The poor rate performance is mainly caused by the anisotropic structure of graphite. During charging and discharging, lithium ions can only enter and exit the graphite layer structure from the edge of the graphite layer, so the diffusion coefficient of lithium ions in and out of the graphite layer is small, resulting in poor rate performance. In addition, when lithium ions are inserted or extracted, different deformation stresses are generated in different directions, and the deformation stresses cannot be offset by each other and then appear to expand in some directions, resulting in cycle capacity degradation.

technical solutions

According to various embodiments of the present application, a high-rate lithium-ion battery artificial graphite negative electrode material and a preparation method thereof are provided. The preparation method uses easily graphitized coke as a raw material, and is processed by pulverization, surface treatment, oxidation modification, granulation, graphite Graphite negative electrode material with special structure is obtained through the steps of chemicalization, coating, demagnetization and sieving. It has the advantages of simple process, no burr on the particle surface, smooth and flat surface, etc. Energy density and good processability.

A method for preparing an artificial graphite negative electrode material for a high-rate lithium ion battery, comprising the following steps: (1) pulverization and shaping: pulverizing raw coke to obtain micropowder with an average particle size D50 of 2-50 μm, and then chemically etching it Shape and obtain ellipsoid-like appearance precursor A; (2) Surface oxidation treatment: perform superficial layer oxidation treatment on precursor A in step (1) to obtain precursor B; (3) coating and carbonization: step (2) ), the precursor B and the coating agent are mixed in a certain proportion, and then subjected to low-temperature carbonization treatment, and then reduced to room temperature and sieved to obtain the precursor C; (4) Composite granulation: the precursor C in step (3) is bonded with After mixing, it is placed in a granulation device, and then granulated in an inert atmosphere, and then sieved after cooling to obtain a precursor D; (5) Graphitization: the precursor D obtained in step (4) is subjected to graphitization treatment (6) Mixing and screening: the graphitized sample in step (5) is mixed and screened to obtain a finished product.

In one embodiment, in step (1), the raw material coke is coal-based needle coke before calcination, coal-based needle coke after calcination, petroleum-based needle coke before calcination, and petroleum-based needle coke after calcination , 1 or a combination of at least two of coal-based pitch coke and petroleum-based pitch coke; the ash content of the raw coke is not more than 10%, and the sulfur content is not more than 5%; wherein, the volatile content of the precalcined coke is not more than More than 15%; the volatile content of the calcined coke is not more than 7%; the pulverization adopts one or a combination of at least two kinds of mechanical mill, jet mill, ball mill and roller mill; the end point judgment condition of the pulverization is: The volume average particle size D50 is 2-50 μm; the chemical etching and shaping is specifically carried out in a stirring, rotating or fluidized bed reactor, using saturated water vapor and/or carbon dioxide as the etchant, at 400~600 ℃ The reaction is carried out for 1-6 hours; the sphericity of the ellipsoid-like morphology precursor A is 0.51-0.99.

In one embodiment, in step (2), the superficial layer oxidation treatment is specifically: in an oxygen-containing atmosphere, in a converter at 300 ~ 500 ℃, the graphitization precursor oxidation reaction treatment 1-5 hour; wherein, the volume fraction of oxygen in the oxygen-containing atmosphere is 5-100%, and the balance gas is one or more combinations of nitrogen, argon, helium, and argon; the surface layer of the precursor B particles is 3 μm The oxygen content (mass fraction) within the depth is 0.5~8%.

In one embodiment, in step (3), the coating is to mix the precursor B and the coating agent through solid phase and/or liquid phase, and obtain the precursor C through low-temperature carbonization; wherein, the coating is The coating agent is various monosaccharide, polysaccharide compound, organic acid, tar, linear polymer and resin with low degree of polymerization, specifically starch, sucrose, glucose, citric acid, malic acid, tartaric acid, acetic acid, succinic acid, One or a combination of at least two of oxalic acid, coal tar, vinyl tar, aromatic oil, pine tar, polyacrylonitrile, polypyrrolidone, polyvinyl alcohol, polycarbonate, polyacrylamide, polyethylene glycol and polystyrene The solvent mixed in the liquid phase is 1 or at least 2 combinations in water, ethanol, washing oil, toluene and tetrahydrofuran; the mass ratio of the coating agent and the precursor B is 5～50:100; The low-temperature carbonization is carried out in a high-temperature furnace under the protection of inert gas at 500-1000°C for 1-3 hours.

In one embodiment, in step (4), the binder is pitch and/or resin, wherein pitch is specifically petroleum pitch or coal pitch, and the resin may be phenolic resin, epoxy resin, furan resin and a combination of 1 or at least 2 of the furfural resins; the mass ratio of the binder to the precursor C is 10 to 40:100; the granulation equipment is a heating equipment with rolling and/or rotating mechanisms; The granulation temperature is 400-700°C; the reaction time is 1-6 hours; the gas used in the inert atmosphere is 1 or at least 2 of nitrogen, helium, neon, argon, krypton and xenon. combination of species.

In one embodiment, in step (5), the temperature of the graphitization treatment is 2600-3200° C.; the graphitization treatment time is 12-36 hours.

In one embodiment, in step (6), the mixing is carried out in a mixer, and the mixing conditions are: a stirring speed of 100-500 rpm and a time of 15-60 min.

In one embodiment, in step (4) and step (6), a vibrating screen is used for the screening, specifically, a standard screen with a mesh size of more than 200 meshes is used, and the screen is removed.

A high-rate lithium-ion battery artificial graphite negative electrode material, the high-rate lithium-ion battery artificial graphite negative electrode material is prepared by the preparation method of any one of claims 1-8.

In one embodiment, the particle size of the high-rate lithium-ion battery artificial graphite negative electrode material is 9-70 μm, the true density is ≥ 2.10 g/cm , the tap density is ≥ 0.80 g/cm , and the specific surface area is 0.5-5 m 2 /g, the initial discharge capacity is ≥ 350 mAh/g, the initial discharge efficiency is ≥ 92%, the 1C capacity retention rate is greater than 62%, and the 3C capacity retention rate is greater than 22%.

beneficial effect

The invention has simple preparation process, low cost, easy quality control and high cost performance, and is an ideal negative electrode material for power batteries. This process adopts single particle shaping and spheroidization, and then increases the degree of amorphousness and surface affinity through surface oxidation, which helps to improve the uniformity and stability of subsequent coating. The surface rounding treatment improves the processing performance of the material; the smaller primary particle size, the superficial layer oxidation control, combined with the special secondary granulation process and liquid phase coating modification make the rate performance of the obtained material jump significantly, and the material interface The wettability and liquid retention of the electrolyte have been significantly improved, and it is suitable for high-end fast charging and has good industrial application prospects.

.

Embodiments of the present invention

In order to facilitate understanding of the present invention, the present invention will be described more fully below. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

Example 1: The calcined petroleum needle coke was crushed and shaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm, the aggregates were put into a fluidized bed, saturated steam was introduced, and the temperature was 450°C. The reaction was carried out for 3 hours to obtain the precursor A, which was then transferred to the rotary kiln, air was introduced, and the reaction was carried out at 300 ° C for 2 hours to obtain the precursor B; In the machine, the reaction was kneaded at 150 ° C for 4 hours, the kneaded material was put into the vertical reaction kettle, and under nitrogen protection, the temperature was raised to 600 ° C at 5 ° C/min for 2 hours, and the precursor C was obtained by sieving after cooling. ; The precursor C and the petroleum pitch with a softening point of 150°C and an average particle size of 7 μm were mixed uniformly according to the mass ratio of 100:15 and then put into a horizontal reactor. Under nitrogen protection, the temperature was raised to 600°C at 5°C/min. The granulation reaction was carried out at ℃ for 4 hours, and the precursor D was obtained by sieving after cooling. The precursor D was graphitized at 2800 ℃ for 24 hours, and the high-rate artificial graphite product was obtained by discharging and sieving.

Example 2: The calcined coal needle coke was pulverized and reshaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm, the aggregates were put into a fluidized bed, saturated steam was introduced, and the temperature was 450°C. The reaction was carried out for 2 hours to obtain the precursor A, which was then transferred to the rotary kiln, air was introduced, and the reaction was carried out at 350 ° C for 1 hour to obtain the precursor B; Then, the initial solid content was adjusted to 50% with water, kneaded for 4 hours at 150 °C, and the kneaded material was put into the vertical reaction kettle. After cooling, the precursor C was obtained by sieving; the precursor C was mixed with petroleum asphalt with a softening point of 200 °C and an average particle size of 7 μm according to a mass ratio of 100:12, and then put into a horizontal reaction kettle. At 5°C/min, the temperature was raised to 600°C for 4 hours to carry out the granulation reaction, and after cooling, the precursor D was obtained by sieving, and the precursor D was graphitized at 2800°C for 24 hours. Graphite products.

Example 3: The calcined petroleum coke was crushed and reshaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm, the aggregates were put into a fluidized bed, saturated steam was introduced, and the reaction was carried out at 450°C After 3 hours, the precursor A was obtained, then transferred to the rotary kiln, air was introduced, and the reaction was carried out at 300 ° C for 4 hours to obtain the precursor B; the precursor B and the aromatic oil were put into the kneader according to the mass ratio of 100:15 , kneaded at 150 ° C for 4 hours, put the kneaded material into the vertical reactor, under nitrogen protection, heated to 600 ° C at 5 ° C/min for 2 hours, cooled and sieved to obtain precursor C; Precursor C and petroleum pitch with a softening point of 200 °C and an average particle size of 7 μm were mixed uniformly in a mass ratio of 100:12 and then put into a horizontal reactor. Under the protection of nitrogen, the temperature was raised to 600 °C at 5 °C/min. The granulation reaction was carried out for 4 hours, and the precursor D was obtained by sieving after cooling. The precursor D was graphitized at 2800° C. for 24 hours, and the high-rate artificial graphite product was obtained by discharging and sieving.

Example 4: The pre-calcined petroleum needle coke was crushed and shaped by a mechanical mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm. The aggregates were put into a fluidized bed, and saturated steam was introduced, and the temperature was 500 ° C. React for 1 hour to obtain Precursor A, then transfer to the rotary kiln, let in air, and react at 300°C for 2 hours to obtain Precursor B; put Precursor B and sucrose into the kneader according to the mass ratio of 100:10 , then adjust the initial solid content to 50% with water, knead the reaction at 150 ° C for 4 hours, put the kneaded material into the vertical reaction kettle, under nitrogen protection, heat up to 600 ° C at 5 ° C/min and keep it for 2 hours, After cooling, sieving to obtain precursor C; Precursor C and petroleum asphalt with a softening point of 250 ° C and an average particle size of 7 μm are mixed uniformly according to a mass ratio of 100:10 and then put into a horizontal reaction kettle. Under nitrogen protection, The temperature was raised to 600°C at 5°C/min for 4 hours to carry out the granulation reaction. After cooling, the precursor D was obtained by sieving. The precursor D was graphitized at 2800°C for 24 hours, and the high-rate artificial graphite product was obtained by discharging and screening. .

Example 5: The pre-calcined coal needle coke was crushed and shaped by a mechanical mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm, the aggregates were put into a fluidized bed, carbon dioxide was introduced, and the reaction was carried out at 650 ° C for 4 After 2 hours, the precursor A was obtained, and then transferred to the rotary kiln, air was introduced, and the reaction was carried out at 300 ° C for 2 hours to obtain the precursor B; the precursor B and the ethylene tar were put into the kneader according to the mass ratio of 100:10, The kneading reaction was carried out at 150°C for 4 hours, the kneaded material was put into the vertical reactor, and under nitrogen protection, the temperature was raised to 600°C at 5°C/min for 2 hours, and after cooling, the precursor C was obtained by sieving; Body C and petroleum asphalt with a softening point of 150 °C and an average particle size of 7 μm were mixed uniformly according to a mass ratio of 100:15 and then put into a horizontal reactor. The granulation reaction was carried out for 24 hours, and the precursor D was obtained by sieving after cooling. The precursor D was graphitized at 2800° C. for 24 hours, and the high-rate artificial graphite product was obtained by discharging and sieving.

Comparative Example 1: The calcined petroleum needle coke was crushed and shaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm. The aggregates were put into a rotary kiln, air was introduced, and the reaction was carried out at 300 °C 2 hours to obtain the precursor A; the precursor A and the pine tar are put into the kneader according to the mass ratio of 100:10, and the reaction is kneaded at 150 ° C for 4 hours, and the kneaded material is put into the vertical reactor. Under the protection, the temperature was raised to 600°C for 2 hours at 5°C/min, and the precursor B was obtained by sieving after cooling; the precursor C and the petroleum asphalt with a softening point of 150°C and an average particle size of 7 μm were in a mass ratio of 100: 15 After mixing evenly, put it into a horizontal reactor, under nitrogen protection, heat up to 600 °C at 5 °C/min for 4 hours to carry out granulation reaction, after cooling, sieve to obtain precursor D, and the precursor D is heated at 2800 °C After graphitization for 24 hours, a comparative sample was obtained by discharging and sieving.

Comparative Example 2: The calcined petroleum needle coke was crushed and shaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm. The aggregates were put into a fluidized bed, and carbon dioxide was introduced into the aggregate at 450 ° C. The reaction was carried out for 3 hours to obtain the precursor A. The precursor A and the pine tar were put into the kneader according to the mass ratio of 100:10, and the reaction was kneaded at 150 ° C for 4 hours. The kneaded material was put into the vertical reactor. Under nitrogen protection, the temperature was raised to 600 °C for 2 hours at 5 °C/min, and the precursor C was obtained by sieving after cooling. After 15 minutes of mixing evenly, put it into a horizontal reactor, under nitrogen protection, heat up to 600 °C at 5 °C/min and keep it for 4 hours to carry out granulation reaction, after cooling, sieve to obtain precursor D, and the precursor D at 2800 °C Under graphitization for 24 hours, the material is sieved to obtain a comparative sample.

Comparative Example 3: The calcined petroleum needle coke was crushed and shaped by a roller mill-shaping integrated machine to obtain aggregates with an average particle size D50 of 9 μm. The reaction was carried out for 3 hours to obtain precursor A, which was then transferred to a rotary kiln, air was introduced, and reacted at 300°C for 2 hours to obtain precursor B; The petroleum asphalt was mixed uniformly according to the mass ratio of 100:15 and then put into the horizontal reaction kettle. Under the protection of nitrogen, the temperature was raised to 600 °C at 5 °C/min and kept for 4 hours to carry out the granulation reaction. After cooling, the precursor D was obtained by screening and screening. The precursor D was graphitized at 2800° C. for 24 hours, and the material was sieved to obtain a comparative sample.

The particle size, specific surface area and tap density of the artificial graphite anode materials in Examples 1 to 5 and Comparative Examples 1 to 3 were tested respectively, and the results are listed in Table 1. The name and model of the instrument used in the test are: particle size: Malvern laser particle size analyzer MS2000; specific surface area: Canta specific surface area analyzer NOVA2000e; tap density: HY-100 powder density tester.

Table 1.

.

The first specific capacity, first coulombic efficiency and rate lithium intercalation performance tests were performed on the graphite anode materials in Examples 1 to 5 and Comparative Examples 1 to 3 by using the half-cell test method. The results are listed in Table 1. The test method of the half-cell is as follows: using N-methylpyrrolidone as a solvent to prepare a polyvinylidene fluoride solution with a mass fraction of 6~7%, and mixing the graphite negative electrode material, polyvinylidene fluoride, and conductive carbon black in a mass ratio of 91.6:6.6: 1.8 Mix evenly, apply it on the copper foil, and put the coated pole piece into a vacuum drying oven with a temperature of 110°C for 4 hours of vacuum drying. Then, a 2430 type button battery was assembled in an argon-filled German Michaelona glove box, and the three-component mixed solvent of 1mol/L LiPF6 was mixed according to EC:DMC:EMC=1:1:1 (volume ratio) The electrochemical performance of the assembled half-cell was tested on the LAND battery test system of Wuhan Jinnuo Electronics Co., Ltd., and the charge-discharge voltage ranged from 5 mV to 2.0 V. The obtained half-cell performance parameters are shown in Table 1.

By comparing the results of the examples and the comparative examples, it can be seen that more lithium intercalation sites and channels can be provided after the synergistic treatment of chemical etching surface modification, superficial layer oxidation and thin layer hard carbon coating, which significantly improves the rate and fast charging of the material. performance. Compared with the comparative example, the first reversible specific capacity of the artificial graphite materials obtained in Examples 1 to 5 exceeds 356 mAh/g, and the first effect is greater than 93%, showing good powder characteristics and electrochemical performance. It can be seen from Table 1 that the capacity retention rate of the samples of the examples under the high current of 1C is greater than 62%, and the capacity retention rate of the samples of the examples under the high current of 3C is greater than 22%, which is significantly better than the comparative example. It can be seen from the above results that the artificial graphite negative electrode material prepared by the method of the present invention has a large first reversible capacity, a high first efficiency, and at the same time has ultra-high rate performance and powder processing characteristics.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1, a preparation method of high rate lithium ion battery artificial graphite negative electrode material, is characterized in that, comprises the steps:

(1) Pulverization and shaping: the raw coke is pulverized to obtain micropowder with an average particle size D50 of 2-50 μm, and then chemical etching and shaping are performed to obtain a precursor A with an ellipsoid-like morphology;

(2) Surface oxidation treatment: Precursor A in step (1) is subjected to shallow surface oxidation treatment to obtain precursor B;

(3) Coating and carbonization: The precursor B and the coating agent in step (2) are mixed in a certain proportion, and then subjected to low-temperature carbonization treatment, and then the precursor C is obtained after screening at room temperature;

(4) Composite granulation: the precursor C and the binder in step (3) are mixed and placed in a granulation device, and then granulated in an inert atmosphere, cooled and screened to obtain the precursor D;

(5) Graphitization: the precursor D obtained in step (4) is subjected to graphitization treatment;

(6) Mixing and sieving: The graphitized sample in step (5) is mixed and sieved to obtain a finished product.

2. The method for preparing an artificial graphite negative electrode material for a high-rate lithium ion battery according to claim 1, wherein in step (1), the raw coke is a pre-calcined coal-based needle coke and a post-calcined coal-based coke One or a combination of at least two of needle coke, pre-calcined petroleum-based needle coke, calcined petroleum-based needle coke, coal-based pitch coke, and petroleum-based pitch coke; the ash content of the raw coke is not more than 10% , the sulfur content is not more than 5%; wherein, the volatile content of the calcined coke is not more than 15%; the volatile content of the calcined coke is not more than 7%; 1 or a combination of at least 2 of them; the end point determination condition of the pulverization is that the volume average particle size D50 is 2-50 μm; the chemical etching and shaping are specifically carried out in a stirring, rotating or fluidized bed reactor , using saturated water vapor and/or carbon dioxide as an etchant, and reacting at 400-600° C. for 1-6 hours; the sphericity of the ellipsoid-like morphology precursor A is 0.51-0.99.

3. The method for preparing an artificial graphite negative electrode material for a high-rate lithium ion battery according to claim 1, wherein in step (2), the superficial layer oxidation treatment is specifically: in an oxygen-containing atmosphere, in a converter The graphitization precursor is oxidized and treated for 1-5 hours under the condition of 300-500 ℃; wherein, the volume fraction of oxygen in the oxygen-containing atmosphere is 5-100%, and the balance gas is nitrogen, argon, helium, One or more combinations in argon; the oxygen content (mass fraction) within 3 μm of the surface layer of the precursor B particles is 0.5-8%.

4. The method for preparing an artificial graphite negative electrode material for a high rate lithium ion battery according to claim 1, wherein in step (3), the coating is to pass the precursor B and the coating agent through solid-phase and /or liquid phase mixing and carbonization at low temperature to obtain precursor C; wherein, the coating agent is various monosaccharides, polysaccharide compounds, organic acids, tars, linear polymers and low polymerization degree resins, specifically starch , sucrose, glucose, citric acid, malic acid, tartaric acid, acetic acid, succinic acid, oxalic acid, coal tar, vinyl tar, aromatic oil, pine tar, polyacrylonitrile, polypyrrolidone, polyvinyl alcohol, polycarbonate, polypropylene One or at least two combinations of amide, polyethylene glycol and polystyrene; the solvent mixed in the liquid phase is one or at least two combinations of water, ethanol, washing oil, toluene, and tetrahydrofuran; The mass ratio of the coating agent to the precursor B is 5-50:100; the low-temperature carbonization is performed in a high-temperature kiln under the protection of an inert gas at 500-1000° C. for 1-3 hours.

5. The method for preparing an artificial graphite negative electrode material for a high-rate lithium ion battery according to claim 1, wherein in step (4), the binder is pitch and/or resin, wherein the pitch is specifically petroleum Pitch or coal pitch, the resin can be one or at least two combinations of phenolic resin, epoxy resin, furan resin and furfural resin; the mass ratio of the binder and the precursor C is 10 to 40: 100; the granulation equipment is a heating device with a rolling and/or rotating mechanism; the granulation temperature is 400-700°C; the reaction time is 1-6 hours; the gases used in the inert atmosphere are nitrogen, helium One or a combination of at least two of gas, neon, argon, krypton and xenon.

6. The method for preparing an artificial graphite negative electrode material for a high rate lithium ion battery according to claim 1, wherein in step (5), the temperature of the graphitization treatment is 2600-3200°C; The processing time is 12 to 36 hours.

7. The preparation method of artificial graphite negative electrode material for high-rate lithium ion battery according to claim 1, characterized in that, in step (6), the mixing is carried out in a mixing machine, and the mixing conditions are: The stirring speed is 100~500 rpm, and the time is 15~60 min.

8. The method for preparing high-rate lithium-ion battery artificial graphite negative electrode material according to claim 1, characterized in that, in step (4) and step (6), vibrating screen is used for the screening, specifically, a vibrating screen is used for screening through 200 The standard sieve above the mesh, take the sieve and cut the material.

9. A high-rate lithium-ion battery artificial graphite negative electrode material, characterized in that the high-rate lithium-ion battery artificial graphite negative electrode material is prepared by the preparation method described in any one of claims 1-8.

10. The high-rate lithium-ion battery artificial graphite negative electrode material according to claim 9, wherein the high-rate lithium-ion battery artificial graphite negative electrode material has a particle size of 9 to 70 μm, and a true density of ≥ 2.10 g/cm , Tap density ≥ 0.80g/cm3, specific surface area 0.5~5 m2/g, initial discharge capacity ≥ 350 mAh/g, initial discharge efficiency ≥ 92%, 1C capacity retention rate greater than 62%, 3C capacity retention rate greater than twenty two%.