Coal-based graphite anode material, its preparation method and application

Abstract

The present invention relates to the field of carbon materials, and discloses a coal-based graphite anode material, a preparation method thereof and an application. The coal-based graphite anode material has a crystallite size L in the c-axis direction obtained by XRD c and a crystallite size L in the a-axis direction a satisfying the following conditions: 30 nm ≤ L c ≤ 70 nm, formula (I); 50 nm ≤ L a ≤ 120 nm, formula (II); the graphitization degree of the coal-based graphite anode material satisfies the following conditions: 85 ≤ graphitization degree ≤ 93, formula (III). The coal-based graphite anode material has high charge-discharge capacity, high first Coulomb efficiency and excellent rate performance, and its preparation method has simple process and low cost.

Description

Technical Field

[0001] The present invention relates to the field of carbon materials, and specifically relates to a coal-based graphite anode material, a preparation method thereof, and an application thereof. Background Art

[0002] The negative electrode of a lithium-ion battery is mainly a carbon material, including amorphous carbon, natural graphite, and artificial graphite. Graphite has a regular layered structure and excellent electrical conductivity. Its theoretical specific capacity is 372 mA·h / g, and it has high efficiency. It is currently the mainstream anode material. Currently, there are mainly three types of raw materials for developing artificial graphite: isotropic coke, pitch binder, and needle coke. Isotropic coke-based artificial graphite has low crystallinity, high isotropy, low capacity, and high power performance. Needle coke-based artificial graphite has high capacity, but relatively poor rate performance. Pitch binder generally lies between the two.

[0003] CN104681786A discloses a coal-based anode material. The coal-based anode material is composed of a graphitized inner layer, an intermediate layer, and an outer layer distributed on the surface of a coal-based material. Its preparation method includes: crushing the coal-based material; adding a binder, or a mixture of a binder and a modifier; then performing molding and high-temperature graphitization to obtain a finished product.

[0004] CN109319757A discloses a method for preparing a hollow open onion carbon lithium-ion battery anode material. Using a coal-based material as a raw material, it is mixed and heated with nickel salt or nickel metal as a catalyst, so that the nickel salt or nickel metal is uniformly distributed on the surface of the coal-based material particles. After cooling, an open graphite onion carbon layer is formed on the spherical surface. Finally, it is purified by acid-base treatment to obtain graphite onion carbon with a hollow open spherical structure.

[0005] CN107528053A discloses a negative electrode material for a lithium-ion secondary battery, a negative electrode for a lithium-ion secondary battery, and a lithium-ion secondary battery. The negative electrode material for the lithium-ion secondary battery contains a carbon material, and the average interplanar spacing d 002 obtained by X-ray diffraction method is 0.335 nm - 0.340 nm, the volume average particle size (50% D) is 1 μm - 40 μm, the maximum particle size D max is 74 μm or less, and when performing differential thermal analysis in an air stream, it has at least two exothermic peaks in the temperature range of 300 °C or higher and 1000 °C or lower.

[0006] The structures and processes of the anode materials provided by the above-mentioned prior arts are complex, costly, and use acids, alkalis, etc. for purification treatment during the processing, which is not environmentally friendly. More importantly, the rate performance of single-phase graphite in the anode materials of the prior arts is insufficient and cannot meet the actual requirements. Summary of the Invention

[0007] The object of the present invention is to overcome the problems existing in the prior art that the structure of the graphite negative electrode material is complex, the rate performance of single-phase graphite is insufficient, and the preparation process is complex and costly, and to provide a coal-based graphite negative electrode material, a preparation method thereof and an application thereof. The coal-based graphite negative electrode material has high charge and discharge capacity, high initial Coulomb efficiency and excellent rate performance, and its preparation method has a simple process and low cost.

[0008] To achieve the above object, on the one hand, the present invention provides a coal-based graphite negative electrode material, characterized in that the microcrystalline size L in the c-axis direction of the coal-based graphite negative electrode material obtained by XRD c and the microcrystalline size L in the a-axis direction a meet the following conditions:

[0009] 30nm ≤ L c ≤ 70nm, formula (I);

[0010] 50nm ≤ L a ≤ 120nm, formula (II);

[0011] The graphitization degree of the coal-based graphite negative electrode material meets the following conditions:

[0012] 85 ≤ graphitization degree ≤ 93, formula (III).

[0013] On the second aspect, the present invention provides a preparation method of a coal-based graphite negative electrode material, characterized in that the method comprises the following steps:

[0014] (1) Crushing coal to obtain coal particles;

[0015] (2) Graphitizing the coal particles to obtain the coal-based graphite negative electrode material;

[0016] Wherein, the coal meets the following conditions: vitrinite reflectance ≥ 2; volatile matter ≤ 10wt%; ash content ≤ 10wt%; the conditions of the graphitization include: controlling the actual maximum power transmission of the graphitization furnace transformer ≥ 3,000kW, and the continuous power transmission time of the actual maximum power transmission is 1-100h.

[0017] On the third aspect, the present invention provides a coal-based graphite negative electrode material prepared by the above preparation method.

[0018] On the fourth aspect, the present invention provides an application of the above coal-based negative electrode material in at least one of lithium ion batteries, energy storage materials, mechanical components and graphite electrodes.

[0019] Through the above technical solutions, the coal-based graphite negative electrode material, the preparation method thereof and the application thereof provided by the present invention obtain the following beneficial effects:

[0020] (1) The coal-based graphite anode material provided by the present invention has excellent electrochemical performance. In particular, it can significantly improve the rate performance of a battery including the coal-based graphite anode material while maintaining a relatively high charge-discharge capacity and the first Coulomb efficiency, thereby achieving the best balance among the three. Specifically, the charge-discharge capacity of the coal-based graphite anode material is ≥ 330 mAh / g, the first Coulomb efficiency is ≥ 90%, and the 2C / 0.2C capacity retention rate is ≥ 35%.

[0021] (2) The I110 / I004 of the coal-based graphite anode material provided by the present invention is ≥ 0.30, indicating that the coal-based graphite anode material has a high degree of isotropy. Further, the grain size of the coal-based graphite anode material is small, thereby further improving the rate performance of the graphite anode material.

[0022] (3) The cost of preparing the coal-based graphite anode material of the present invention is low, the process is simple and easy to implement; the raw materials are rich and easy to obtain. Description of the Drawings

[0023] Figure 1 is the TEM photograph of the coal-based graphite anode material provided in Example 1. Detailed Embodiments

[0024] The endpoints and any values disclosed in this article for a range are not limited to the exact range or value. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the values between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0025] The first aspect of the present invention provides a coal-based graphite anode material, characterized in that the microcrystalline size L in the c-axis direction of the coal-based graphite anode material obtained by XRD c and the microcrystalline size L in the a-axis direction a meet the following conditions:

[0026] 30 nm ≤ L c ≤ 70 nm Formula (I);

[0027] 50 nm ≤ L a ≤ 120 nm Formula (II);

[0028] The graphitization degree of the graphite anode material meets the following conditions: 85 ≤ graphitization degree ≤ 93 Formula (III).

[0029] In the present invention, the coal-based graphite anode material satisfying the above-mentioned conditions has the characteristics of high isotropy and small grain size. As a result, there are many channels for lithium ions to embed and extract, and the path is short. On the premise of maintaining a high charge-discharge capacity and the first Coulomb efficiency, the rate performance of the battery including the coal-based graphite anode material can be significantly improved, thus achieving the best balance among the three.

[0030] In the present invention, the graphitization degree G of the coal-based graphite anode material is calculated according to the following formula:

[0031] G = (0.344 - d 002 ) / (0.344 - 0.3354), where the d 002 value is calculated by the Bragg equation.

[0032] In the present invention, as Figure 1 shown by TEM, the graphite anode material is homogeneous.

[0033] Further, when 30nm ≤ L c ≤ 50nm, the rate performance, charge-discharge capacity and first Coulomb efficiency of the coal-based graphite anode material are further improved.

[0034] Further, when 55nm ≤ L a ≤ 100nm, the rate performance, charge-discharge capacity and first Coulomb efficiency of the coal-based graphite anode material are further improved.

[0035] Further, when 86 ≤ graphitization degree ≤ 92, the rate performance, charge-discharge capacity and first Coulomb efficiency of the coal-based graphite anode material are further improved.

[0036] According to the present invention, the interlayer spacing d 002 of the (002) crystal plane obtained by XRD of the coal-based graphite anode material satisfies the following conditions:

[0037] 0.3350nm ≤ d 002 ≤ 0.3380nm Formula (IV).

[0038] According to the present invention, when the interlayer spacing of the (002) crystal plane satisfies 0.3360nm ≤ d 002 ≤ 0.3370m, the coal-based graphite anode material has more excellent comprehensive performance.

[0039] According to the present invention, the peak intensity I110 of the (110) crystal plane and the peak intensity I004 of the (004) crystal plane obtained by XRD of the coal-based graphite anode material satisfy the following conditions:

[0040] I110 / I004 ≥ 0.30 Formula (V).

[0041] In the present invention, the degree of isotropy of the coal-based graphite anode material satisfying the above-mentioned conditions is further improved, thereby enabling further improvement of the rate performance of the coal-based anode material.

[0042] Further, when 0.35 ≤ I110 / I004 ≤ 0.85, the coal-based graphite anode material has more excellent rate performance.

[0043] According to the present invention, the ash content of the coal-based graphite anode material ≤ 1000 ppm.

[0044] In the present invention, the ash content of the coal-based graphite anode material is measured by the method of GB / T3521. The coal-based graphite anode material provided by the present invention has a low ash content, which can significantly improve the overall uniformity of the coal-based graphite anode material.

[0045] Further, the ash content of the coal-based graphite anode material ≤ 500 ppm.

[0046] The second aspect of the present invention provides a preparation method of a coal-based graphite anode material, characterized in that the method comprises the following steps:

[0047] (1) Crushing coal to obtain coal particles;

[0048] (2) Graphitizing the coal particles to obtain the coal-based graphite anode material;

[0049] Wherein, the coal satisfies the following conditions: vitrinite reflectance ≥ 2; volatile matter ≤ 10 wt%; ash ≤ 10 wt%; the conditions of the graphitization include: controlling the actual maximum power transmission of the graphitization furnace transformer ≥ 3,000 kW, and the continuous power transmission time of the actual maximum power transmission is 1 - 100 h.

[0050] In the present invention, the graphitization equipment can be the graphitization equipment commonly used in the industry in this field. Specifically, the graphitization equipment can be selected from at least one of an Acheson furnace, a box furnace, an internal series furnace, a vertical graphitization furnace, and a horizontal graphitization furnace.

[0051] The present invention develops a graphite anode material with low cost and a unique micro-nano structure using coal as a raw material. When preparing the graphite anode material according to the method provided by the present invention, high-value utilization and clean and efficient conversion of coal can be realized.

[0052] In the present invention, when coal satisfying the above conditions is selected as a raw material for preparing the coal-based graphite anode material, the prepared coal-based graphite anode material can have a moderate degree of graphitization, and has the characteristics of small grain size and high degree of isotropy, thereby significantly improving the rate performance, charge-discharge capacity, and initial Coulomb efficiency of the coal-based graphite anode material.

[0053] In the present invention, the vitrinite reflectance of the coal is measured by the method of GB / T 6948 of the national standard, and the volatile content and ash content of the coal are both measured by the method of GB / T 30732 of the national standard.

[0054] According to the present invention, the coal satisfies the following conditions: vitrinite reflectance ≥ 2.35; volatile matter ≤ 10 wt%; ash ≤ 6 wt%.

[0055] In the present invention, conventional equipment in the art, such as a jet mill, can be used to pulverize the coal.

[0056] According to the present invention, in step (1), the particle size D of the coal particles 50 is 1 - 100 μm, preferably 5 - 30 μm.

[0057] According to the present invention, the method further includes the steps of shaping and / or classifying the coal particles.

[0058] According to the present invention, step (2) includes the following steps:

[0059] (2 - 1) Carbonize the coal particles to obtain an intermediate;

[0060] (2 - 2) Graphitize the intermediate to obtain the coal - based graphite anode material.

[0061] In the present invention, carbonizing the coal particles before graphitization can remove the volatile matter or ash in the coal particles, avoid agglomeration caused by the escape of the volatile matter or ash during the graphitization process, and at the same time improve the graphitization degree of the product. Furthermore, the charge - discharge capacity and the first Coulombic efficiency of the battery including the coal - based graphite anode material are higher, thus achieving the best balance among capacity, efficiency and rate.

[0062] According to the present invention, in step (2 - 1), the conditions for carbonization include: 400 - 1800 °C, and the carbonization time is 1 - 10 h.

[0063] In the present invention, the carbonization is carried out in the presence of an inert atmosphere.

[0064] According to the present invention, in step (2), the conditions for graphitization include: controlling in the graphitization equipment, the actual maximum power transmission of the transformer is 5,000 - 50,000 kW, and the continuous power transmission time of the actual maximum power transmission is 5 - 50 h.

[0065] Furthermore, the conditions for graphitization include: controlling in the graphitization equipment, the actual maximum power transmission of the transformer is 10,000 - 30,000 kW, and the continuous power transmission time of the actual maximum power transmission is 8 - 40 h.

[0066] The third aspect of the present invention provides a coal-based graphite anode material prepared by the above preparation method.

[0067] The fourth aspect of the present invention provides the application of the above coal-based graphite anode material in at least one of lithium-ion batteries, energy storage materials, mechanical components and graphite electrodes.

[0068] In the present invention, the lithium-ion battery containing the above coal-based graphite anode material has excellent electrochemical performance. Specifically, the charge-discharge capacity of the lithium-ion battery containing the above coal-based graphite anode material is ≥330 mAh / g, the first Coulomb efficiency is ≥90%, and the 2C / 0.2C capacity retention rate is ≥35%.

[0069] The present invention will be described in detail below through examples.

[0070] (1) XRD analysis

[0071] XRD analysis of the coal-based graphite anode material:

[0072] Interlayer spacing d 002 , L a , L c and I110 / I004 are all obtained through test analysis by a D8 Advance type X-ray diffractometer of Bruker AXS GmbH. XRD is calibrated by the silicon internal standard method, and the d 002 value is calculated by the Bragg formula . L a , L c is calculated by the Scherrer formula;

[0073] (2) Particle size (D 10 , D 50 , D 90 )

[0074] D50 is obtained through testing by a Malvern Mastersizer 2000 laser particle size analyzer of Malvern Instruments Ltd. in the UK;

[0075] (3) The morphology of the anode material is characterized by a transmission electron microscope (TEM).

[0076] (4) Battery performance

[0077] The charge-discharge capacity and the first Coulomb efficiency of the battery are tested by a CT2001A battery tester of Wuhan Blue Electronic Co., Ltd. The current is 0.1C (1C = 350 mAh / g), and the voltage is 0 - 3V.

[0078] (5) The vitrinite reflectance of coal was measured by the method of GB / T 6948, and the volatile matter content and ash content of coal were both measured by the method of GB / T 30732.

[0079] Example 1

[0080] (1) Coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash 2.6 wt%) was crushed by a crusher to obtain powder with D 50 = 10 μm, and after classification, coal particles were obtained;

[0081] (2-1) The coal particles were carbonized at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0082] (2-2) The intermediate was graphitized in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer was 22,000 kW, and the continuous power transmission time of the actual maximum power transmission was 20 h; a graphite negative electrode material was obtained, and after sieving, product A1 was obtained.

[0083] The TEM photograph of the graphite negative electrode material is as Figure 1 shown. It can be seen from Figure 1 that product A1 has a high degree of isotropy and small grain size.

[0084] Example 2

[0085] (1) Coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash 2.6 wt%) was crushed by a crusher to obtain coal particles with D 50 = 10 μm;

[0086] (2-1) The coal particles were carbonized at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0087] (2-2) The intermediate was graphitized in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer was 22,000 kW, and the continuous power transmission time of the actual maximum power transmission was 35 h; a graphite negative electrode material was obtained, and after sieving, product A2 was obtained.

[0088] Example 3

[0089] (1) Coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash 2.6 wt%) was crushed by a crusher to obtain coal particles with D 50 = 10 μm;

[0090] (2-1) The coal particles were carbonized at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0091] (2-2) Graphitize the intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 22,000 kW, and the continuous power transmission time of the actual maximum power transmission is 10 h; obtain the graphite negative electrode material, and perform sieving to obtain product A3.

[0092] Example 4

[0093] (1) Crush coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash content 2.6 wt%) through a crusher to obtain coal particles with D 50 = 10 μm.

[0094] (2-1) Carbonize the coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0095] (2-2) Graphitize the intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 10,000 kW, and the continuous power transmission time of the actual maximum power transmission is 20 h; obtain the graphite negative electrode material, and perform sieving to obtain product A4.

[0096] Example 5

[0097] (1) Crush coal (vitrinite reflectance 2.269; volatile matter 6.83 wt%; ash content 9.3 wt%) through a crusher to obtain D 50 = 10 μm of powder, and after classification, obtain coal particles;

[0098] (2-1) Carbonize the coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0099] (2-2) Graphitize the intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 22,000 kW, and the continuous power transmission time of the actual maximum power transmission is 20 h; obtain the graphite negative electrode material, and perform sieving to obtain product A5.

[0100] Example 6

[0101] (1) Crush coal (vitrinite reflectance 2.269; volatile matter 6.83 wt%; ash content 9.3 wt%) through a crusher to obtain D 50 = 10 μm of powder, and after classification, obtain coal particles;

[0102] (2-1) Carbonize the coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0103] (2-2) Graphitize the intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 5,000 kW, and the continuous power transmission time at the actual maximum power transmission is 20 h; obtain the graphite negative electrode material, and perform sieving to obtain product A6.

[0104] Example 7

[0105] (1) Crush coal (vitrinite reflectance 2.269; volatile matter 6.83 wt%; ash content 9.3 wt%) through a crusher to obtain D 50 powder with a particle size of 10 μm, and after classification, obtain coal particles;

[0106] (2-1) Carbonize the coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0107] (2-2) Graphitize the intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 22,000 kW, and the continuous power transmission time at the actual maximum power transmission is 5 h; obtain the graphite negative electrode material, and perform sieving to obtain product A7.

[0108] Example 8

[0109] Prepare the coal-based graphite negative electrode material according to the method of Example 1, except that: in step (2-1), the carbonization conditions are different from those in Example 1. Specifically, the carbonization temperature is 400 °C and the time is 0.5 h.

[0110] Example 9

[0111] Prepare the coal-based graphite negative electrode material according to the method of Example 1, except that: in step (2-1), the carbonization conditions are different from those in Example 1. Specifically, the carbonization temperature is 2200 °C and the time is 15 h.

[0112] Example 10

[0113] (1) Crush coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash content 2.6 wt%) through a crusher to obtain D 50 coal particles with a particle size of 10 μm;

[0114] (2) Graphitize the coal particles in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 22,000 kW, and the continuous power transmission time at the actual maximum power transmission is 20 h; obtain the graphite negative electrode material, and perform sieving to obtain product A10.

[0115] Comparative Example 1

[0116] (1) Crush coal (vitrinite reflectance 1.947; volatile matter 12.5 wt%; ash content 9.4 wt%) through a jet mill to obtain D50 coal particles with a size of 10 μm;

[0117] (2-1) Carbonize the above coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0118] (2-2) Graphitize the above intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 22,000 kW, and the continuous power transmission time at the actual maximum power transmission is 20 h; obtain a graphite negative electrode material, and perform sieving to obtain product D1.

[0119] Comparative Example 2

[0120] (1) Crush coal (vitrinite reflectance 2.445; volatile matter 7.7 wt%; ash content 2.6 wt%) through a jet mill to obtain D 50 coal particles with a size of 10 μm;

[0121] (2-1) Carbonize the above coal particles at 1000 °C for 2 hours under an inert gas to obtain an intermediate;

[0122] (2-2) Graphitize the above intermediate in a graphitization furnace. In the graphitization furnace, the actual maximum power transmission of the transformer is 600 kW, and the continuous power transmission time at the actual maximum power transmission is 20 h; obtain a graphite negative electrode material, and perform sieving to obtain product D2.

[0123] Comparative Example 3

[0124] Prepare the negative electrode material according to the method of Example 1, except that: use pitch coke instead of coal. Obtain the negative electrode material D3.

[0125] Characterize the negative electrode materials prepared in the examples and comparative examples, and the results are shown in Table 1.

[0126] Table 1

[0127] Example Ash content / ppm Graphitization degree <![CDATA[d 002 / nm]]> <![CDATA[L c / nm]]> <![CDATA[L a / nm]]> I110 / I004 Example 1 257 91.4％ 0.33614 44.6 93.7 0.806 Example 2 183 91.5％ 0.33613 41.8 94.1 0.801 Example 3 223 90.3％ 0.33623 44.8 92.3 0.497 Example 4 268 90.0％ 0.33626 43.4 95.7 0.487 Example 5 487 88.8％ 0.33636 31 103 0.357 Example 6 326 86.3％ 0.33658 34.1 68 0.455 Example 7 294 87.9％ 0.33644 34.1 73.6 0.412 Example 8 265 89.9％ 0.33627 40.2 82.2 0.467 Example 9 197 89.2％ 0.33633 34.9 73 0.481 Example 10 287 89.1％ 0.33634 34.4 63.2 0.467 Comparative Example 1 398 80.2％ 0.33710 17.8 41.8 0.975 Comparative Example 2 746 82.6％ 0.33690 29.8 62.6 0.418 Comparative Example 3 212 93.8％ 0.33593 61.5 158.9 0.285

[0128] Test Example

[0129] Mix the negative electrode materials prepared in the examples and comparative examples with conductive carbon black Super P and binder polyvinylidene fluoride (PVDF) evenly according to a mass ratio of 92:3:5, add the solvent N-methylpyrrolidone (NMP), stir to form a uniform negative electrode slurry, and use a spatula to evenly coat the negative electrode slurry on an aluminum foil, dry to obtain a negative electrode sheet. After cutting the sheet, transfer it to a MBraun2000 glove box (Ar atmosphere, H2O and O2 concentrations less than 0.1×10 -6 volume %), use a lithium metal sheet as a reference electrode, and assemble a button cell. Test the electrochemical performance of the button cell, and the test results are shown in Table 2.

[0130] Table 2

[0131]

[0132]

[0133] As can be seen from the results of Table 1 and Table 2, the charge-discharge capacity and the first Coulombic efficiency of the battery using the coal-based anode material prepared in Examples 1-10 of the present invention are better, and the best balance among the charge-discharge capacity, the first Coulombic efficiency and the rate performance of the battery can be achieved.

[0134] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the disclosed content of the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of a graphite anode material, characterized in that, The method includes the following steps: (1) Crushing coal to obtain coal particles; (2) Graphitizing the coal particles to obtain the graphite anode material; Wherein, the coal meets the following conditions: vitrinite reflectance ≥ 2; volatile matter ≤ 10 wt%; ash content ≤ 10 wt%; the conditions for graphitization include: controlling in the graphitization equipment, the actual maximum power transmission of the transformer ≥ 3,000 kW, and the continuous power transmission time of the actual maximum power transmission is 1 - 100 h; Wherein, step (2) includes the following steps: (2-1) Carbonizing the coal particles to obtain an intermediate; (2-2) Graphitizing the intermediate to obtain the graphite anode material; Wherein, in step (2-1), the conditions for carbonization include: carbonization temperature is 400 - 1800 °C, and carbonization time is 1 - 10 h; The crystallite size L in the c-axis direction obtained by XRD of the graphite negative electrode material c and the crystallite size L in the a-axis direction a meet the following conditions: 30nm ≤ L c ≤ 70nm of formula (I); 50nm ≤ L a ≤ 120nm, Formula (II); The graphitization degree of the graphite anode material meets the following conditions: 86.3% ≤ graphitization degree ≤ 91.5% formula (III).

2. The method according to claim 1, wherein, The coal meets the following conditions: vitrinite reflectance ≥ 2.35; volatile matter ≤ 10 wt%; ash content ≤ 6 wt%.

3. The method according to claim 1 or 2, wherein In step (1), the particle size D of the coal particles 50 is 1 - 100 μm.

4. The method according to claim 1 or 2, wherein In step (1), the particle size D of the coal particles 50 is 5 - 30 μm.

5. The method according to claim 1 or 2, wherein The method further includes the steps of shaping and / or classifying the coal particles.

6. The method according to claim 1 or 2, wherein In step (2), the conditions for graphitization include: controlling in the graphitization equipment, the actual maximum power transmission of the transformer is 5,000 - 50,000 kW, and the continuous power transmission time of the actual maximum power transmission is 5 - 50 h.

7. The method according to claim 1 or 2, wherein In step (2), the conditions for graphitization include: controlling in the graphitization equipment, the actual maximum power transmission of the transformer is 10,000 - 30,000 kW, and the continuous power transmission time of the actual maximum power transmission is 8 - 40 h.

8. The graphite anode material prepared by the preparation method according to any one of claims 1 - 7.

9. The graphite negative electrode material according to claim 8, wherein 30nm ≤ L c ≤ 50nm.

10. The graphite negative electrode material according to claim 8 or 9, wherein 55nm ≤ L a ≤ 100nm.

11. The graphite negative electrode material according to claim 8 or 9, wherein, 87.9% ≤ graphitization degree ≤ 91.5%.

12. The graphite anode material according to claim 8 or 9, wherein, The interlayer spacing d of the (002) crystal plane obtained by XRD of the graphite anode material 002 satisfies the following conditions: 0.3350 nm ≤ d 002 ≤ 0.3380 nm Formula (IV).

13. The graphite negative electrode material according to claim 12, wherein, The interlayer spacing d of the (002) crystal plane obtained by XRD of the graphite anode material 002 satisfies the following condition: 0.3360 nm ≤ d 002 ≤ 0.3370 nm.

14. The graphite negative electrode material according to claim 8 or 9, wherein, The peak intensity I110 of the (110) crystal plane and the peak intensity I004 of the (004) crystal plane obtained by XRD of the graphite anode material meet the following conditions: I110 / I004 ≥ 0.30 formula (V).

15. The graphite anode material according to claim 14, wherein, The peak intensity I110 of the (110) crystal plane and the peak intensity I004 of the (004) crystal plane obtained by XRD of the graphite anode material meet the following conditions: 0.35 ≤ I110 / I004 ≤ 0.

85.

16. The graphite negative electrode material according to claim 8 or 9, wherein, The ash content of the graphite anode material ≤ 1000 ppm.

17. The graphite negative electrode material according to claim 16, wherein, The ash content of the graphite anode material ≤ 500 ppm.

18. The application of the graphite anode material according to any one of claims 8 - 17 in at least one of lithium-ion batteries, energy storage materials, mechanical components, and graphite electrodes.

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