A smokeless coal-based graphite anode material and its preparation method

Abstract

This invention belongs to the technical field of lithium-ion battery anode materials, specifically relating to anthracite-based graphite anode material and its preparation method. The anthracite-based graphite anode material includes primary anthracite-based artificial graphite particles with a particle size D50 of 5-10 μm and secondary anthracite-based artificial graphite particles with a particle size D50 of 11-20 μm. The preparation method includes: sequentially subjecting anthracite to mechanical crushing, flotation, and mechanical pulverization, followed by gradient pre-carbonization treatment to obtain pre-carbonized material; graphitizing the pre-carbonized material to obtain primary anthracite-based artificial graphite particles; mixing the primary anthracite-based artificial graphite particles with a binder and then mechanically granulating under heating conditions, followed by carbonization to obtain secondary anthracite-based artificial graphite particles. The anthracite-based graphite anode material of this invention exhibits high compaction density, large discharge capacity, and good rate performance, and the process is simple, showing good compatibility with existing artificial graphite anode processes, making it suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the technical field of lithium-ion battery anode materials, specifically relating to anthracite-based graphite anode material and its preparation method. Background Technology

[0002] With continuous economic development and accelerated industrialization, global energy demand has increased dramatically. The energy resource crisis and environmental problems have made the development of clean, efficient, and sustainable energy sources imperative. Renewable energy sources such as wind and solar power are important drivers for achieving sustainable development. Furthermore, the automotive industry, as one of the world's major sources of greenhouse gases, has become a global focus. Research shows that electrified transportation is crucial for achieving carbon neutrality. Therefore, electric vehicles (EVs) powered by lithium-ion batteries (LIBs) and plug-in hybrid electric vehicles (PHEVs) are gradually gaining attention and experiencing explosive growth. The International Energy Agency (IEA) predicts that the global electric vehicle industry will grow significantly over the next decade, with the global EV fleet expected to reach 230 million vehicles by 2030. Despite rapid progress in the long driving range and low cost of electric vehicles, consumer acceptance remains low, primarily due to the long charging time and persistent range anxiety.

[0003] Graphite, the most thermodynamically stable allotrope of carbon, is a commercially successful anode material for lithium-ion batteries (LIBs). Graphite is formed by the π-π stacking of layered hexagonal carbon atoms through weak van der Waals interactions, with sp2 hybridized carbon atoms arranged in a hexagonal ring structure. Graphite anode materials are divided into two types: natural graphite and artificial graphite. While natural graphite has a high specific capacity (>350 mAh / g), its unstable structure and susceptibility to co-intercalation of solvent molecules lead to sheet shedding during charge and discharge, resulting in poor battery cycle performance and safety. The core process for preparing artificial graphite is the Atchison process, an energy-intensive process (approximately 3000℃). This process heavily relies on graphite precursors; currently, petroleum coke (including needle coke) and coal tar pitch are primarily used as raw materials for preparing artificial graphite. However, these negative electrode materials, namely traditional graphite negative electrode materials, have small interlayer spacing and long migration paths. Under the high current of fast charging, lithium electrodes are prone to deposit on the graphite surface, forming lithium dendrites. This not only reduces battery capacity but also punctures the separator, causing internal short circuits and leading to safety issues.

[0004] Anthracite is in the transitional stage of coal to graphite. Its molecular structure is similar to that of raw materials such as petroleum coke and pitch coke. It can be transformed into graphite at high temperatures. In particular, anthracite has a high carbon content (>93%), moderate volatile matter (<10%), abundant pores, and contains certain graphite microcrystal / microstructure. The carbon atom layers have good preferred orientation in the short range. It can be transformed into graphite at high temperatures with high yield and low price, making it an ideal material for preparing lithium-ion battery anode materials.

[0005] Therefore, to overcome the fast-charging challenge of graphite anode materials, existing technologies include Chinese patent CN114094079B, which uses alkali metals such as KOH to etch pores in graphite sheets to enhance lithium-ion transport. However, this method requires alkali metals, significantly impacting production equipment and alkali metal processing. Japanese patent JP2000243398 uses pitch pyrolysis gas to treat the graphite surface, but its effect on improving the material's morphology is limited, resulting in a low improvement in electrical performance. US patent US2006001003 introduces a catalyst, improving fast charge / discharge performance and cycle performance through catalyst intercalation and efficient graphitization; however, this method increases process costs and presents engineering challenges such as catalyst-induced spraying.

[0006] Therefore, none of the aforementioned existing technologies can effectively improve the fast charging and compaction density problems of artificial graphite anode materials. Summary of the Invention

[0007] To address the problems of complex processes requiring special pore-forming techniques or high energy consumption for small particle sizes in existing technologies, resulting in poor fast-charging performance and low compaction density of the prepared artificial graphite anode materials, this invention provides anthracite-based graphite anode material and its preparation method. This invention controls the ash and sulfur content of anthracite within a certain range, utilizing sulfur etching and the in-situ escape of minerals from the ash to form a porous structure. The resulting anthracite-based graphite anode material exhibits high compaction density, large discharge capacity, and good rate performance. Furthermore, the process is simple and has good compatibility with existing artificial graphite anode processes, making it suitable for industrial production.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] The first aspect of this invention is a method for preparing anthracite-based graphite anode material, comprising the following steps:

[0010] Step 1: The anthracite is subjected to mechanical crushing, flotation, and mechanical pulverization in sequence, followed by gradient pre-carbonization treatment to obtain pre-carbonized material;

[0011] Step 2: Graphitize the pre-carbonized material to obtain anthracite-based artificial graphite primary particles.

[0012] Furthermore, the preparation method also includes step 3: mixing the primary anthracite-based artificial graphite particles with a binder and then mechanically granulating them under heating conditions, followed by carbonization to obtain secondary anthracite-based artificial graphite particles.

[0013] Preferably, the anthracite contains 1-3 wt% sulfur. The sulfur in the anthracite is preferably present primarily as FeS2, with the FeS2 percentage preferably being ≥45%.

[0014] Preferably, the anthracite has a particle size D50 of 75-200μm after mechanical crushing, an ash content of 2-5wt% after flotation, and a particle size D50 of 5-10μm after mechanical pulverization.

[0015] Preferably, the specific conditions for the gradient pre-carbonization treatment are as follows: it is carried out under argon or helium, the final pre-carbonization temperature is 1050℃, and the gradient pre-carbonization curve is as follows: the heating rate in the range of 0-600℃ is 20-30℃ / min, preferably 26-30℃ / min; the heating rate in the range of 600-900℃ is 10-18℃, preferably 10-15℃ / min; and the heating rate in the range of 900-1100℃ is 2-5℃ / min, preferably 2-3℃ / min.

[0016] Preferably, the specific conditions for the graphitization treatment are: graphitization temperature of 2800-3200℃, graphitization time of 16-32h, and the graphitization furnace is one of an induction vacuum graphitization furnace, an Acheson crucible furnace, an Acheson box furnace, or an Acheson internal furnace.

[0017] Preferably, the adhesive is one of oxidized asphalt, cross-linked asphalt, phenolic resin, epoxy resin, polyester resin, vinyl ester, bismaleimide, polyimide, and cyanate ester.

[0018] Preferably, the mechanical granulation process is as follows: anthracite-based artificial graphite primary particles and binder are mixed at a mass ratio of (90-98):(2-10) at room temperature and high speed of 150-500 rpm for 30-60 min, then the speed is reduced to 20-100 rpm and heated to 150-300℃ for fusion granulation for 30-60 min; the specific carbonization conditions are as follows: carbonization is carried out in a nitrogen atmosphere at a heating rate of 5℃ / min for 1-2 h, and the final carbonization temperature is 1200-1400℃.

[0019] The second aspect of the present invention is an anthracite-based graphite anode material prepared by the method described in the first aspect, comprising primary anthracite-based artificial graphite particles with a particle size D50 of 5-10 μm and secondary anthracite-based artificial graphite particles with a particle size D50 of 11-20 μm. Its performance parameters are shown in Table 1.

[0020] Table 1

[0021] Serial Number Projects and parameters index 1 Particle size (D50) 5-20μm 2 <![CDATA[True density (g / cm 3 )]]> ≥2.1 3 Ash content (wt%) ≤0.03 4 <![CDATA[Compaction density (g / cm 3 )]]> ≥1.75 5 <![CDATA[Specific surface area (m 2 / g)]]> ≤1.0-4.0 6 Initial discharge specific capacity (mAh / g) ≥345.0 7 First charge / discharge efficiency (%) ≥92.0 8 Rate performance (5C / 0.2C) ≥82.0

[0022] A third aspect of the present invention is a lithium-ion battery anode material, comprising the anthracite-based graphite anode material described in the second aspect.

[0023] A fourth aspect of the present invention is a lithium-ion battery comprising the lithium-ion battery negative electrode material described in the third aspect.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The anthracite-based graphite anode material prepared by this invention possesses a reasonable pore structure. This pore structure is not achieved through the external introduction of activators, but rather by fully utilizing the structural characteristics of the coal itself, thus realizing in-situ pore formation. These pores originate from two aspects: firstly, anthracite with the highest FeS2 content is selected as the raw material, utilizing the sulfur naturally present in the coal to rapidly escape in gaseous form under thermochemical action, etching the coal surface to form pores; secondly, anthracite of relatively low metamorphic grade, such as No. 2 or No. 3 anthracite, is used, utilizing the volatile matter and minerals within it to escape and form certain pores. The synergistic effect of these two methods achieves the formation of a porous structure within the coal.

[0026] 2. Anthracite with the highest FeS2 content is selected as raw material. During the rapid heating process in the low temperature range (0-600℃), FeS2 can be fully decomposed, and the S in it is converted into organic sulfur, which realizes the etching of coal in the thermochemical process of graphitization; while the Fe in it can undergo chemical reaction and act as an in-situ catalyst in the graphitization process to promote the graphitization process of coal.

[0027] 3. Gradient pre-carbonization technology was employed to effectively control the pore structure of coal. The low-temperature zone primarily facilitates the removal of moisture and low-temperature volatiles, while a rapid heating rate is maintained in the high-temperature section to allow more pyrolysis gases, such as coal gas, to escape. In the high-temperature zone, a slow heating rate is used, which falls within the coal condensation reaction temperature range. This increases the pyrolysis time of coal in this zone and enhances the selectivity of the thermal reaction, resulting in parallel and sequential pyrolysis reactions and the formation of a certain stable oriented structure.

[0028] 4. A heated mechanical granulation process was introduced. Through the combined action of binders and mechanical extrusion, particles of different sizes are pressed and adhered together, effectively fusing and granulating primary particles to form secondary particles, thus improving tap density and compaction density. Primary particle polymerization provides shorter lithium-ion channels, thereby improving rate performance.

[0029] 5. For the first time, a non-nitrogen inert atmosphere pre-carbonization technology was proposed, which avoids nitrogen participating in the thermal reaction during pyrolysis and reduces the content of sp2 carbon.

[0030] 6. By using in-situ pore-forming technology and heated mechanical granulation technology, the process steps are simplified and the production cost is reduced. Attached Figure Description

[0031] Figure 1 This is a SEM image of the primary particles of the anthracite-based artificial graphite of this invention.

[0032] Figure 2 This is a SEM image of the secondary particles of anthracite-based artificial graphite of the present invention.

[0033] Figure 3 This is a comparative SEM image of coke-based artificial graphite for this invention.

[0034] Figure 4 This is the XRD pattern of the anthracite-based artificial graphite of the present invention.

[0035] Figure 5 This is a charge-discharge curve of the anthracite-based artificial graphite of the present invention.

[0036] Figure 6 The graph shows the cycle performance (0.5C) of the anthracite-based artificial graphite of this invention. Detailed Implementation

[0037] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0038] Example 1

[0039] Anthracite (sulfur content 1.5 wt%) was mechanically crushed to a particle size D50 of 75 μm, and then the ash content was reduced to 2.5 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 of 10 μm. Then, pre-carbonization was carried out under a helium atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, to obtain pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 30℃ / min was used in the 0-600℃ (low temperature zone), a heating rate of 15℃ / min was used in the 600-900℃ (medium temperature zone), and a slow heating rate of 2℃ / min was used in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in a medium-frequency induction graphitization furnace at 2800℃ for 24 hours to obtain anthracite-based artificial graphite primary particles. Next, the anthracite-based artificial graphite primary particles were mixed with oxidized asphalt (softening point 200℃) at a mass ratio of 98:2 at room temperature. The mixer speed was 300 rpm, and after mixing for 30 minutes, the speed was reduced to 100 rpm, and the granulation temperature was adjusted to 220℃ for 60 minutes. Finally, the mixture was carbonized for 1 hour at a heating rate of 5℃ / min, a final temperature of 1300℃, and under nitrogen protection. This yielded anthracite-based artificial graphite secondary particles with a particle size of 20 μm, which are the anthracite-based fast-charging graphite anode material. These were assembled into a button-type half-cell with a specific capacity of 352.4 mAh / g and an initial coulombic efficiency of 93.1%. Further assembly with a lithium iron phosphate cathode into a pouch cell resulted in a 5C / 0.2C rate performance of 86%.

[0040] Example 2

[0041] Anthracite (sulfur content 1.2 wt%) was mechanically crushed to a particle size D50 of 80 μm, and then the ash content was reduced to 2 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 of 5 μm. Then, pre-carbonization was carried out under an argon atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 25℃ / min was used in the 0-600℃ (low temperature zone), 18℃ / min in the 600-900℃ (medium temperature zone), and a slow heating rate of 3℃ / min in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in an Atchison crucible graphitization furnace at 3200℃ for 32 hours to obtain anthracite-based artificial graphite primary particles. Next, the anthracite-based artificial graphite primary particles were mixed with oxidized asphalt (softening point 240℃) at a mass ratio of 94:6 at room temperature. The mixer speed was 500 rpm, and after mixing for 60 minutes, the speed was reduced to 100 rpm, and the granulation temperature was adjusted to 255℃ for 60 minutes. Finally, the mixture was carbonized for 2 hours under nitrogen protection at a heating rate of 5℃ / min and a final temperature of 1400℃. This yielded anthracite-based artificial graphite secondary particles with a particle size of 11 μm, which are the anthracite-based fast-charging graphite anode material. These were assembled into a button-type half-cell with a specific capacity of 365.2 mAh / g and an initial coulombic efficiency of 92.4%. Further assembly with a lithium iron phosphate cathode into a pouch cell resulted in a 5C / 0.2C rate performance of 88.2%.

[0042] Example 3

[0043] Anthracite (sulfur content 1.0 wt%) was mechanically crushed to a particle size of D50 200 μm, and then the ash content was reduced to 5 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 8 μm. Then, pre-carbonization was carried out under an argon atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 20℃ / min was used in the 0-600℃ (low temperature zone), a heating rate of 10℃ / min was used in the 600-900℃ (medium temperature zone), and a slow heating rate of 5℃ / min was used in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in a medium-frequency induction graphitization furnace at 2900℃ for 16 hours to obtain anthracite-based artificial graphite primary particles. Next, the anthracite-based artificial graphite primary particles were mixed with oxidized asphalt (softening point 130℃) at a mass ratio of 90:10 at room temperature. The mixer speed was 150 rpm, and after mixing for 45 minutes, the speed was reduced to 80 rpm, and the granulation temperature was adjusted to 150℃ for 50 minutes. Finally, the mixture was carbonized for 2 hours under nitrogen protection at a heating rate of 5℃ / min and a final temperature of 1200℃. This yielded anthracite-based artificial graphite secondary particles with a particle size of 17μm, which are the anthracite-based fast-charging graphite anode material. These were assembled into a button-type half-cell with a specific capacity of 348.6 mAh / g and an initial coulombic efficiency of 92.2%. Further assembly with a lithium iron phosphate cathode into a pouch cell resulted in a 5C / 0.2C rate performance of 89%.

[0044] Example 4

[0045] Anthracite (sulfur content 3.0 wt%) was mechanically crushed to a particle size of D50 120 μm, and then the ash content was reduced to 3 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 of 8 μm. Then, pre-carbonization was carried out under a helium atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 26℃ / min was used in the 0-600℃ (low temperature zone), a heating rate of 12℃ / min was used in the 600-900℃ (medium temperature zone), and a slow heating rate of 4℃ / min was used in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in a chamber graphitization furnace at 3100℃ for 20 hours to obtain anthracite-based artificial graphite primary particles. When assembled into a button cell, it has a specific capacity of 360.8 mAh / g and an initial coulombic efficiency of 92.8%; when further matched with a lithium iron phosphate cathode, it is assembled into a pouch cell with a 5C / 0.2C rate performance of 85%.

[0046] Example 5

[0047] Anthracite (sulfur content 2.5 wt%) was mechanically crushed to a particle size of D50 180 μm, and then the ash content was reduced to 2.8 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 6 μm. Then, pre-carbonization was carried out under an argon atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 28℃ / min was used in the 0-600℃ (low temperature zone), a heating rate of 16℃ / min was used in the 600-900℃ (medium temperature zone), and a slow heating rate of 5℃ / min was used in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in an internal series graphitization furnace at 3000℃ for 20 hours to obtain anthracite-based artificial graphite primary particles. Next, the anthracite-based artificial graphite primary particles were mixed with bismaleimide (softening point 157℃) at a mass ratio of 98:2 at room temperature. The mixer speed was 300 rpm, and after mixing for 30 minutes, the speed was reduced to 50 rpm, and the granulation temperature was adjusted to 170℃ for 40 minutes. Finally, the mixture was carbonized for 2 hours under nitrogen protection at a heating rate of 5℃ / min and a final temperature of 1400℃. This yielded anthracite-based artificial graphite secondary particles with a particle size of 13μm, which are the anthracite-based fast-charging graphite anode material. These were assembled into a button-type half-cell with a specific capacity of 366.2 mAh / g and an initial coulombic efficiency of 94%. Further assembly with a lithium iron phosphate cathode resulted in a pouch cell with a 5C / 0.2C rate performance of 88%.

[0048] Comparative Example 1

[0049] Low-sulfur petroleum coke (<0.3wt%, ash content ≤0.5wt%) was mechanically crushed to a particle size D50 of 150μm, then further reduced to D50 of 10μm using a mechanical pulverizer. Pre-carbonization was then carried out under a nitrogen atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 25℃ / min was used in the 0-600℃ (low temperature zone), 10℃ / min in the 600-900℃ (medium temperature zone), and a slow heating rate of 2℃ / min in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in an Atchison graphitization furnace at 3000℃ for 30 hours to obtain coke-based artificial graphite primary particles. Next, the coke-based artificial graphite particles were mixed with cross-linked asphalt (softening point 260℃) at a mass ratio of 95:5 at room temperature. The mixer speed was 280 rpm, and after mixing for 30 minutes, the speed was reduced to 60 rpm, and the granulation temperature was adjusted to 280℃ for 60 minutes. Finally, the mixture was carbonized for 1 hour under nitrogen protection at a heating rate of 5℃ / min and a final temperature of 1300℃. This yielded a coke-based fast-charging graphite anode material with a particle size of 20 μm. This material was assembled into a button cell with a specific capacity of 358.2 mAh / g and an initial coulombic efficiency of 94.3%. Further assembly with a lithium iron phosphate cathode into a pouch cell resulted in a 5C / 0.2C rate performance of 68%.

[0050] Comparative Example 2

[0051] Low-sulfur anthracite (sulfur content 0.4 wt%) was mechanically crushed to a particle size D50 of 160 μm, and then the ash content was reduced to 2 wt% by flotation. Next, a mechanical pulverizer was used to further reduce the particle size to D50 of 5 μm. Then, pre-carbonization was carried out under an argon atmosphere using a gradient pre-carbonization process, with a final pre-carbonization temperature of 1050℃, yielding pre-carbonized material. Specific pre-carbonization heating curves were as follows: a heating rate of 25℃ / min was used in the 0-600℃ (low temperature zone), a heating rate of 10℃ / min was used in the 600-900℃ (medium temperature zone), and a slow heating rate of 3℃ / min was used in the 900-1100℃ (high temperature zone). The pre-carbonized material was then placed in a graphite crucible and graphitized in an Atchison graphitization furnace at 3000℃ for 36 hours to obtain anthracite-based artificial graphite primary particles. Next, the anthracite-based artificial graphite primary particles were mixed with cross-linked asphalt (softening point 260℃) at a mass ratio of 97:3 at room temperature. The mixer speed was 400 rpm, and after mixing for 30 minutes, the speed was reduced to 50 rpm, and the granulation temperature was adjusted to 280℃ for 60 minutes. Finally, the mixture was carbonized for 2 hours at a heating rate of 5℃ / min, a final temperature of 1400℃, and under nitrogen protection. This yielded anthracite-based artificial graphite secondary particles with a particle size of 11 μm, which are the anthracite-based fast-charging graphite anode material. These were assembled into a button-type half-cell with a specific capacity of 359.6 mAh / g and an initial coulombic efficiency of 93.6%. Further assembly with a lithium iron phosphate cathode into a pouch cell resulted in a 5C / 0.2C rate performance of 75%.

[0052] Table 2

[0053]

[0054] The above description is only for better explaining the embodiments of the present invention and is not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. A method for preparing anthracite-based graphite anode material, characterized in that, Includes the following steps: Step 1: The anthracite is subjected to mechanical crushing, flotation, and mechanical pulverization in sequence, followed by gradient pre-carbonization treatment to obtain pre-carbonized material; Step 2: Graphitize the pre-carbonized material to obtain anthracite-based artificial graphite primary particles; The anthracite has a sulfur content of 1-3 wt%; the anthracite has a particle size D50 of 75-200 μm after mechanical crushing, an ash content of 2-5 wt% after flotation, and a particle size D50 of 5-10 μm after mechanical pulverization. The specific conditions for the gradient pre-carbonization treatment are as follows: it is carried out under argon or helium, the final pre-carbonization temperature is 1050℃, and the gradient pre-carbonization curve is as follows: the heating rate is 20-30℃ / min in the range of 0-600℃, the heating rate is 10-18℃ in the range of 600-900℃, and the heating rate is 2-5℃ / min in the range of 900-1100℃.

2. The method for preparing anthracite-based graphite anode material according to claim 1, characterized in that, It also includes step 3: mixing the primary anthracite-based artificial graphite particles with a binder and then mechanically granulating them under heating conditions, followed by carbonization to obtain secondary anthracite-based artificial graphite particles.

3. The method for preparing anthracite-based graphite anode material according to claim 1, characterized in that, The specific conditions for the graphitization treatment are as follows: the graphitization temperature is 2800-3200℃, the graphitization time is 16-32h, and the graphitization furnace is one of the following: induction vacuum graphitization furnace, Acheson crucible furnace, Acheson box furnace, or Acheson internal furnace.

4. The method for preparing anthracite-based graphite anode material according to claim 2, characterized in that, The adhesive is one of the following: oxidized asphalt, cross-linked asphalt, phenolic resin, epoxy resin, polyester resin, vinyl ester, bismaleimide, polyimide, and cyanate ester.

5. The method for preparing anthracite-based graphite anode material according to claim 2, characterized in that, The specific process of mechanical granulation is as follows: anthracite-based artificial graphite primary particles and binder are mixed at a mass ratio of (90-98):(2-10) at room temperature and high speed of 150-500 rpm for 30-60 min, then the speed is reduced to 20-100 rpm and heated to 150-300℃ for fusion granulation for 30-60 min; the specific conditions of carbonization are as follows: carbonization is carried out in a nitrogen atmosphere at a heating rate of 5℃ / min for 1-2 h, and the final carbonization temperature is 1200-1400℃.

6. A smokeless coal-based graphite anode material prepared by the preparation method according to any one of claims 1-5, characterized in that, It includes primary anthracite-based artificial graphite particles with a particle size D50 of 5-10 μm and secondary anthracite-based artificial graphite particles with a particle size D50 of 11-20 μm.

7. A lithium-ion battery anode material, characterized in that, Including the anthracite-based graphite anode material as described in claim 6.

8. A lithium-ion battery, characterized in that, Including the lithium-ion battery anode material as described in claim 7.

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