Coke, negative electrode material and battery

Abstract

The present application provides a type of coke, a negative electrode material and a battery. The coke comprises a matrix structure and a spheroidal structure embedded in the matrix structure. In a polarized light microscope image of a single sectioned coke particle at a magnification of 50x, the area of the spheroidal structure accounts for more than or equal to 85%; and the average diameter of the spheroidal structure is R μm, the average thickness of the matrix structure is L μm, and the coke satisfies 5≤R / L≤30. The coke provided by the present application has a high degree of isotropy and can reduce rate performance degradation caused by the directional alignment of graphite; and a negative electrode material prepared from the coke can have both a high capacity and good rate performance.

Description

Coke, negative electrode materials, batteries

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411551319.3, filed with the China National Intellectual Property Administration on October 31, 2024, entitled "Coke, Anode Material, Battery", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of negative electrode material technology, specifically to coke, negative electrode materials, and batteries. Background Technology

[0004] Lithium-ion battery energy storage systems, with their advantages of high energy density, no memory effect, and long cycle life, have been widely used in portable electronic devices, electric vehicles, drones, and other fields. However, current lithium-ion batteries still have considerable room for performance optimization. The electrochemical performance of lithium-ion batteries is closely related to the positive and negative electrode materials. Specifically, negative electrode materials are required to possess characteristics such as low lithium storage potential, high lithium storage capacity, and fast electron conduction. Graphite negative electrode materials have become the mainstream choice for lithium-ion battery negative electrode materials due to their excellent comprehensive electrochemical performance and low price. Among them, artificial graphite negative electrode materials are one of the mainstream negative electrode materials for lithium-ion batteries. Since artificial graphite negative electrodes are mainly prepared by high-temperature graphitization of needle coke, petroleum coke, and pitch coke, the performance of the coke essentially determines the performance of the artificial graphite negative electrode material. Although the specific capacity of graphitized coke is often between 330 and 358 mAh / g, its rate performance is inversely proportional to its capacity, often showing that the higher the capacity, the worse the rate performance.

[0005] To meet the comprehensive performance requirements of artificial graphite anode materials, it is necessary to further develop coke that combines high capacity and high rate performance. Summary of the Invention

[0006] In view of this, this application provides coke, anode material, and battery. By increasing the area ratio of spherical structures in the coke, the isotropy of the coke can be improved, thereby enabling the anode material prepared from the coke to have both high capacity and excellent rate performance.

[0007] In a first aspect, this application provides a coke, the coke comprising a matrix tissue and spheroidal tissue embedded within the matrix tissue; in a polarizing microscope image of a single coke particle after cross-section processing and magnification by 50x, the area of ​​the spheroidal tissue accounts for ≥85%;

[0008] The average diameter of the spheroidal tissue is R μm, the average thickness of the matrix tissue between two adjacent spheroidal tissues is L μm, and the foam satisfies 5 ≤ ​​R / L ≤ 30.

[0009] Secondly, this application provides a negative electrode material, the negative electrode material comprising the graphite negative electrode material obtained by graphitizing the above-mentioned coke.

[0010] Thirdly, this application provides a battery comprising the negative electrode material according to the second aspect.

[0011] The technical solution of this application has at least the following beneficial effects:

[0012] The coke provided in this application controls the area ratio of spheroidal structures to be greater than or equal to 85%, indicating a high proportion of spheroidal structures within the coke. These spheroidal structures are embedded within the matrix structure. Compared to needle-shaped coke, the spheroidal structures enhance the isotropy of the coke particles, which is beneficial for maintaining isotropy during processes such as granulation, carbonization, graphitization, and the preparation of graphitized electrode products. Simultaneously, controlling the coke to satisfy 5≤R / L≤30 effectively reduces the agglomeration of spheroidal structures by utilizing the matrix structure. By improving the stability of the spheroidal structures, the area ratio of spheroidal structures in the coke is increased, thereby enhancing the isotropy of the coke. This results in a negative electrode material made from the coke possessing both high specific capacity and excellent rate performance. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the charge and discharge states of the battery provided in this application;

[0014] Figure 2 shows polarizing microscope images of the focal length at different magnifications provided in Embodiment 1 of this application;

[0015] Figure 3 is a polarizing microscope image of the focal length provided in Embodiment 7 of this application;

[0016] Figure 4 shows the longest distance L between two adjacent globular tissues under the measured field of view. 长 With the shortest distance L 短 A schematic diagram. Detailed Implementation

[0017] To better illustrate this application and facilitate understanding of its technical solutions, the following detailed description is provided. However, the following embodiments are merely simplified examples and do not represent or limit the scope of protection of this application. The scope of protection of this application is determined by the claims.

[0018] Since artificial graphite anodes are mainly prepared by high-temperature graphitization of coke such as needle coke, petroleum coke, and pitch coke, needle coke has high capacity but poor rate performance; while ordinary coke such as petroleum coke and pitch coke has better rate performance but low capacity. Therefore, current coke-based graphite anode materials are difficult to combine high capacity and excellent rate performance, and the properties of the coke basically determine the performance of artificial graphite anode materials.

[0019] This application provides a coke, which includes a matrix tissue and a spheroidal tissue embedded in the matrix tissue; in a polarizing microscope image of a single coke particle after cross-section processing and magnification by 50x, the area of ​​the spheroidal tissue accounts for ≥85%;

[0020] The average diameter of the spheroidal tissue is R μm, and the average thickness of the matrix tissue between two adjacent spheroidal tissues is L μm, satisfying 5 ≤ R / L ≤ 30.

[0021] The mosaic described in this application refers to spheroidal tissue located at least partially within the matrix.

[0022] In the above-mentioned scheme, the coke provided in this application controls the area ratio of spheroidal structures to be greater than or equal to 85%. This indicates that spheroidal structures constitute a significant proportion of the coke, embedded within the matrix structure. Compared to needle-shaped coke, spheroidal structures enhance the isotropy of coke particles, which is beneficial for maintaining isotropy during processes such as granulation, carbonization, graphitization, and the preparation of graphitized electrode products. Simultaneously, controlling the coke to satisfy 5≤R / L≤30 effectively reduces the agglomeration of spheroidal structures by utilizing the matrix structure. By improving the stability of the spheroidal structures, the area ratio of spheroidal structures in the coke is increased, thereby enhancing the isotropy of the coke. This results in a negative electrode material made from the coke possessing both high specific capacity and excellent rate performance.

[0023] In some embodiments, in a polarized image of a single coke particle after cross-section processing and 50x magnification, the area ratio of spheroidal tissue is ≥85%, specifically it can be 85%, 85.24%, 86%, 86.73%, 88%, 88.11%, 90%, 91.82%, 92%, 92.47%, 93.33%, 94.03%, 94.36%, 94.61%, 94.97%, 95%, 96%, or 98%, etc., and is not limited here. When the area ratio of spheroidal tissue in the cross-section of the coke is too small, the area ratio of matrix tissue in the coke increases, which will reduce the overall specific capacity of the coke. Preferably, the area ratio of spheroidal tissue is 85% to 95%.

[0024] In some embodiments, in a polarized mirror image of a single coke particle after cross-sectioning and magnification by 50x, the area ratio of the matrix structure is 5% to 15%, specifically 5%, 5.39%, 5.97%, 6%, 6.67%, 7%, 7.53%, 8%, 8.18%, 9%, 10%, 11%, 11.89%, 12%, 13%, 13.27%, 14%, 14.76%, or 15%, etc., and is not limited here.

[0025] In some embodiments, the average diameter of the spheroidal tissue is R μm, where 50 ≤ R ≤ 150; the specific value of R can be 50, 51.68, 60, 60.46, 62.75, 70, 80, 87.61, 90, 90.26, 100, 105, 110, 110.56, 120, 127.52, 130, 130.02, 140, 146.50 or 150, etc., and of course, it can also be other values ​​within the above range, which are not limited here.

[0026] In some embodiments, the average thickness of the matrix tissue between any two spheroidal tissues is L μm, where 3 ≤ L ≤ 30. The specific value of L can be 3, 3.04, 4, 4.28, 4.78, 5, 5.12, 5.37, 5.63, 5.86, 6, 6.34, 7, 8, 9, 10, 10.6, 15, 20, 25, 28.91, or 30, or other values ​​within the above range, which are not limited here. When the average thickness L of the matrix tissue is too small, the spheroidal tissues are prone to merging, leading to a decrease in the area ratio of spheroidal tissues in the coke and a decrease in the isotropy of the coke. When the L value is too large, the thickness of the matrix tissue between two adjacent spheroidal tissues is too large, which also leads to a decrease in the area ratio of spheroidal tissues in the coke. Controlling the L value within the above range is beneficial to improving the isotropy of the coke.

[0027] In some embodiments, the spheroidal structure includes Brooks-Taylor structures, wherein the proportion of Brooks-Taylor structures in the spheroidal structure is ≥90%. Specifically, this can be 90%, 90.1%, 90.9%, 91%, 91.3%, 91.7%, 91.8%, 92%, 92.5%, 92.6%, 92.7%, 93%, 93.7%, 95%, 95.4%, 96%, 97%, 98%, etc., or other values ​​within the above range, which are not limited here. Controlling the proportion of Brooks-Taylor structures in the spheroidal structure within the above range is beneficial for improving the capacity and rate performance of the graphite anode material prepared from coke.

[0028] It should be noted that the Brooks-Taylor structure is a structure with special molecular arrangement characteristics formed by carbon-containing organic matter after undergoing a series of chemical reactions such as pyrolysis, dehydrogenation, and condensation. From a morphological perspective, the Brooks-Taylor structure presents a spherical or near-spherical shape.

[0029] In some implementations, the coke satisfies 5 ≤ ​​R / L ≤ 30. The R / L ratio can specifically be 5, 5.07, 5.9, 6, 8, 10, 10.7, 12, 15, 16.3, 17.0, 17.44, 18, 18.9, 20, 22.18, 25, 25.5, 28, 29.79, or 30, etc., and is not limited here. When the R / L ratio is too high, the content of the matrix structure decreases significantly, indicating that the spheroidal structures in the coke have merged, and a large number of Brooks-Taylor structures have merged to form sheet-like structures. The isotropy of the coke decreases, leading to a decrease in the rate performance of the graphite anode material prepared from the coke. When the R / L ratio is too low, the diameter of the spheroidal structures in the coke is small, or the thickness of the matrix structure is too large. Although the isotropy of the coke is maintained, it will lead to a decrease in the specific capacity of the anode material prepared from the coke. This application controls the coke to satisfy the above relationship, which can effectively reduce the agglomeration of spheroidal structures by utilizing the matrix structure. By improving the stability of spheroidal structures, the area ratio of spheroidal structures in the coke is increased, thereby improving the isotropy of the coke and improving the rate performance of the anode material prepared from the coke.

[0030] In some embodiments, the ratio R of the longest diameter to the shortest diameter of the spheroidal tissue is... max / R min The value is between 1.0 and 1.5, specifically 1.0, 1.06, 1.1, 1.12, 1.13, 1.2, 1.21, 1.22, 1.26, 1.27, 1.3, 1.31, 1.32, 1.4, or 1.5, etc., and of course, other values ​​within the above range are also possible, without limitation. In this application, controlling the ratio of the longest diameter to the shortest diameter of the spheroidal tissue can help control the sphericity of the spheroidal tissue. Understandably, the closer it is to a sphere, the higher the isotropy of the spheroidal tissue.

[0031] In some embodiments, the coke also includes a dopant element, which includes at least one selected from iron, nickel, aluminum, calcium, vanadium, cobalt, zinc, manganese, sodium, potassium, copper, chromium, magnesium, and silicon.

[0032] In some embodiments, the mass content of any dopant element in the coke is ≤100ppm, specifically 100ppm, 90ppm, 85ppm, 80ppm, 75ppm, 70ppm, 65ppm, 50ppm, 30ppm, 20ppm or 10ppm, etc., and of course, other values ​​within the above range are also possible, which are not limited here.

[0033] In some embodiments, the ash content of the coke at 950°C is ≤0.3%, specifically 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, 0.5%, 0.1%, etc., and is not limited thereto. In this application, controlling the ash content in the coke within the above range is beneficial to improving the conductivity of the graphite anode material prepared from the coke, reducing the interference of ash on the internal electron migration of graphite, effectively reducing the internal resistance of the graphite anode material, and improving the rate performance of the graphite anode material.

[0034] In some embodiments, the volatile matter content of the coke at 900°C is ≤8.5%, specifically it can be 8.5%, 8.2%, 8.0%, 7.5%, 7.0%, 6.0%, 5.0%, 4.0%, 3.0%, 2.0%, 1.0%, etc., and is not limited thereto. In this application, controlling the volatile matter content in the coke is beneficial to increasing the true density of the negative electrode material obtained by coke graphitization, reducing the porosity inside the negative electrode material, and increasing the energy density of the negative electrode material. Furthermore, controlling the volatile matter content can also ensure the safety of the coke during the graphitization process.

[0035] This application also provides a negative electrode material, which includes the graphite negative electrode material obtained by graphitizing the coke as described above.

[0036] In some embodiments, the orientation degree OI of the negative electrode material is 0.8 to 1.1, specifically 0.8, 0.85, 0.9, 0.92, 0.95, 0.98, 0.99, 1.0, 1.02, 1.05, 1.08, or 1.1, or other values ​​within the above range. In this application, controlling the orientation degree of the negative electrode material within the above range allows for a more ordered arrangement of the graphite crystal structure, resulting in higher isotropy of the negative electrode material, closer lithium-ion insertion / extraction rates, reduced internal resistance, and better cycle performance and rate performance.

[0037] In some embodiments, the graphitization degree of the negative electrode material is 92% to 95%, specifically 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, or 95%, etc., and of course, other values ​​within the above range are also possible, without limitation. In this application, controlling the graphitization degree of the negative electrode material within the above range results in a more regular crystal structure of the negative electrode material, which is beneficial to improving the lithium-ion transport efficiency and increasing the capacity retention rate of the negative electrode material during cycling.

[0038] In some embodiments, the median particle size of the negative electrode material is 10 μm to 15 μm; more specifically, it can be 10 μm, 12 μm, 14 μm, 15 μm, 17 μm, 18 μm, 19 μm or 20 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0039] In some embodiments, the true density of the negative electrode material is 2.16 g / cm³. 3 ~2.28g / cm 3 Specifically, it could be 2.15 g / cm³. 3 2.18 g / cm 3 2.20g / cm 3 2.22 g / cm 3 2.24 g / cm 3 2.26 g / cm 3 2.28g / cm 3 Of course, it can also be other numbers within the above range, and is not limited here. Preferably, the true density of the negative electrode material is 2.20 g / cm³. 3 ~2.28g / cm 3 This application controls the true density of the negative electrode material within the above-mentioned range, which is beneficial to improving the energy density of the negative electrode material and enhancing its cycle stability.

[0040] Secondly, this application provides a method for preparing coke, comprising the following steps:

[0041] S10, preparing a first carbon feedstock and a second carbon feedstock, wherein the first carbon feedstock includes aromatic hydrocarbons with a mass content of ≥80% and asphaltenes with a mass content of ≤2.5%; the second carbon feedstock includes aromatic hydrocarbons with a mass content of 40% to 60% and asphaltenes with a mass content of 20% to 45%.

[0042] S20 involves preheating the first and second carbon raw materials separately, mixing the preheated first and second carbon raw materials at a mass ratio of 80-95:5-20, and then coking them to obtain coke.

[0043] In the coke preparation method provided in this application, a first carbon raw material and a second carbon raw material are mixed. Because the first carbon raw material has a high aromatic hydrocarbon content and the second carbon raw material has a high asphaltene content, their compatibility is poor during mixing. The first carbon raw material is blocked by the second carbon raw material, and during coking, the second carbon raw material forms a matrix structure. The first carbon raw material with a high aromatic hydrocarbon content gradually aggregates during coking to form a spheroidal structure, which improves the isotropy of the coke. Simultaneously controlling the mass ratio of the first carbon raw material to the second carbon raw material is beneficial for obtaining coke with a higher proportion of spheroidal structures. The matrix structure formed by the second carbon raw material reduces the agglomeration of the spheroidal structures. In the prepared coke, the spheroidal structures are dispersed and embedded within the matrix structure, which improves the isotropy of the graphitized graphite anode material, thereby giving the anode material high specific capacity and excellent rate performance.

[0044] The preparation method provided in this scheme is described in detail below:

[0045] S10, prepare a first carbon feedstock and a second carbon feedstock, wherein the first carbon feedstock includes aromatic hydrocarbons with a mass content of ≥80% and asphaltenes with a mass content of ≤2.5%; the second carbon feedstock includes aromatic hydrocarbons with a mass content of 40% to 60% and asphaltenes with a mass content of 20% to 45%.

[0046] In some embodiments, the first carbon feedstock is obtained by solvent purification and supercritical extraction from medium- and low-temperature coal tar pitch and / or catalytic cracking slurry.

[0047] In some embodiments, the first carbon feedstock includes aromatic hydrocarbons with a mass content of ≥80%. The specific mass content of the aromatic hydrocarbons can be 80%, 82%, 85%, 87%, 89%, 90%, 92%, 95%, 97%, or 98%, etc., and can be any value within the above range; this application does not impose any limitation on this. Preferably, the mass content of the aromatic hydrocarbons is 83% to 95%.

[0048] In some embodiments, the first carbon raw material includes asphaltene with a mass content ≤ 2.5%. The specific mass content of the asphaltene can be 2.5%, 2.2%, 2.0%, 1.9%, 1.8%, 1.6%, 1.5%, 1.4%, 1.0%, 0.8%, 0.5%, 0.2%, 0.1%, etc., or any value within the above range; this application does not impose any limitation on this. Preferably, the mass content of asphaltene is 0.25% to 2.3%.

[0049] In some embodiments, the first carbon raw material also includes a saturated content of ≤19% by mass, specifically 19%, 18%, 15%, 12%, 10%, 8% or 5%, etc., and of course any value within the above range. This application does not limit it here, but 4% to 18% is preferred.

[0050] In some embodiments, the first carbon raw material further includes quinoline insoluble matter with a mass content of ≤0.05%, specifically 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.005%, or 0.001%, etc., or any value within the above range. This application does not impose any restrictions here, but 0.01% to 0.04% is preferred.

[0051] In some embodiments, the density (at 20°C) of the first carbon feedstock is 1 g / cm³. 3 ~1.10g / cm 3 Specifically, it can be 1.0 g / cm³. 3 1.01 g / cm 3 1.02g / cm 3 1.03 g / cm 3 1.04 g / cm 3 1.05g / cm 3 1.07 g / cm 3 1.08g / cm 3 1.09 g / cm 3 Or 1.1g / cm 3 Of course, it can also be any value within the above range, and this application does not impose any restrictions on it.

[0052] In some embodiments, the second carbon feedstock is obtained by removing saturated components and a certain amount of aromatic components from high-temperature coal tar pitch / heavy residue oil using a solvent method.

[0053] In some embodiments, the second carbon feedstock comprises 40% to 60% aromatic hydrocarbons by mass. The specific mass content of the aromatic hydrocarbons can be 40%, 42%, 45%, 47%, 49%, 50%, 52%, 55%, 57%, or 60%, etc., and can be any value within the above range; this application does not impose any limitation thereon. Preferably, the mass content of the aromatic hydrocarbons is 45% to 55%.

[0054] In some embodiments, the second carbon raw material includes asphaltene with a mass content of 20% to 45%. The specific mass content of the asphaltene can be 20%, 22%, 25%, 28%, 30%, 32%, 35%, 40%, 42%, 44%, or 45%, etc., or any value within the above range; this application does not impose any limitation on this. Preferably, the mass content of asphaltene is 20% to 43%.

[0055] In some embodiments, the second carbon raw material also includes a saturated content of ≤20% by mass, specifically 20%, 19%, 18%, 15%, 12%, 10%, 8%, or 5%, etc., and of course, any value within the above range is also acceptable. This application does not impose any restrictions here, but 8% to 15% is preferred.

[0056] In some embodiments, the second carbon raw material further includes 0.5% to 2.0% by mass of quinoline insolubles, specifically 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, or 2.0%, etc., or any value within the above range. This application does not impose any restrictions here, but 0.6% to 1.8% is preferred.

[0057] In some embodiments, the density (at 20°C) of the second carbon feedstock is 1.15 g / cm³. 3 ~1.25g / cm 3 Specifically, it can be 1.15 g / cm³. 3 1.16 g / cm 3 1.18 g / cm 3 1.2g / cm 3 1.21 g / cm 3 1.22g / cm 3 1.23g / cm 3 1.24 g / cm 3 Or 1.25g / cm 3 Of course, it can also be any value within the above range, and this application does not impose any restrictions here. S20, the first carbon raw material and the second carbon raw material are preheated respectively, the preheated first carbon raw material and the second carbon raw material are mixed at a mass ratio of 80-95:5-20, and then coking is performed to obtain coke.

[0058] In some embodiments, the preheating temperature of the first carbon raw material is 150°C to 300°C, specifically 150°C, 160°C, 170°C, 180°C, 200°C, 220°C, 250°C, 280°C, or 300°C, etc., and is not limited thereto. Preferably, the preheating temperature of the first carbon raw material is 250°C to 280°C.

[0059] In some embodiments, the preheating temperature of the second carbon raw material is 250°C to 400°C, specifically 250°C, 260°C, 270°C, 280°C, 300°C, 320°C, 350°C, 380°C, or 400°C, etc., and is not limited thereto. Preferably, the preheating temperature of the second carbon raw material is 280°C to 380°C.

[0060] In some embodiments, a first carbon raw material is added to a heated stirring tank A, the temperature of which is 150°C to 300°C; at the same time, a second carbon raw material is added to a heated stirring tank B, the temperature of which is 250°C to 400°C; the mixture is stirred and mixed under the action of a mechanical pump to obtain a preheated material.

[0061] In some embodiments, the preheated first carbon raw material and the second carbon raw material are added to a mixing tank at a mass ratio of 80-95:5-20 and mixed. The mixed material is then heated to 450°C-550°C to obtain a mixture.

[0062] In some embodiments, the first carbon raw material and the second carbon raw material are in a mass ratio of 80-95:5-20, specifically 80:20, 85:15, 88:12, 90:10, 92:8, 95:5, etc., or other values ​​within the above ratio range, which are not limited here.

[0063] In this application, by controlling the mass ratio of the first carbon raw material to the second carbon raw material and the composition of the carbon raw material, it is beneficial to the formation and dispersion of spheroidal structures in the coke, which is beneficial to increasing the area ratio of spheroidal structures in the coke, thereby improving the isotropy of the coke, so that the anode material made from the coke has both high specific capacity and excellent rate performance.

[0064] In some embodiments, the stirring rate during mixing is 50 r / min to 150 r / min, specifically 50 r / min, 60 r / min, 70 r / min, 80 r / min, 100 r / min, 120 r / min, 140 r / min, or 150 r / min, etc., and of course, other values ​​within the above range are also possible, and are not limited here. Preferably, the stirring rate during mixing is 60 r / min to 140 r / min.

[0065] In some embodiments, the heating rate of the mixed material is 5℃ / min to 10℃ / min, specifically 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0066] In some embodiments, the coking temperature is 450℃ to 550℃, specifically 450℃, 460℃, 470℃, 480℃, 500℃, 520℃, 530℃, 540℃, or 550℃, or other values ​​within the above range, which are not limited here. Preferably, the coking temperature is 480℃ to 530℃.

[0067] In some embodiments, the coking pressure is 0.1 MPa to 0.3 MPa, specifically 0.1 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, 0.25 MPa, 0.28 MPa, 0.29 MPa or 0.3 MPa, etc., or other values ​​within the above range, which are not limited here.

[0068] In some implementations, the coking time is 24h to 30h, specifically 24h, 26h, 28h, 29h, or 30h, etc., and is not limited here.

[0069] By controlling the stirring rate, coking temperature, pressure, and time, the degree of coking of the coke can be adjusted, the size of the spheroidal structures in the coke can be adjusted, the agglomeration of the spheroidal structures in the coke can be reduced, and the area ratio of the spheroidal structures in the coke can be increased, thereby improving the isotropy of the coke. This allows the anode material made from the coke to have both high specific capacity and excellent rate performance.

[0070] In some embodiments, the preparation method further includes: pulverizing the coke, performing carbonization and graphitization treatments to obtain the negative electrode material.

[0071] In some embodiments, the carbonization temperature is 1000℃ to 1250℃, specifically 1000℃, 1050℃, 1100℃, 1150℃, 1200℃ or 1250℃, etc., and of course, other values ​​within the above range are also possible, which are not limited here.

[0072] In some implementations, the carbonization time is 3h to 8h, specifically 3h, 4h, 5h, 6h, 7h or 8h, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0073] In some embodiments, the graphitization temperature is 2900℃~3200℃, specifically 2900℃, 2900℃, 2950℃, 2980℃, 3000℃, 3050℃, 3100℃ or 3200℃, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0074] In some implementations, the graphitization treatment time is 1h to 6h, specifically 1h, 2h, 3h, 4h, 5h or 6h, etc., and of course other values ​​within the above range are also possible, which are not limited here.

[0075] This application controls the temperature and time of carbonization treatment, as well as the temperature and time of graphitization, to ensure that the coke is fully graphitized, thereby obtaining a negative electrode material with excellent performance.

[0076] Thirdly, embodiments of the present invention also provide a battery. Figure 1 is a schematic diagram of the discharge state of the battery provided in this application embodiment. As shown in Figure 1, the battery includes a casing and an electrode assembly. The electrode assembly includes a positive electrode 1, a negative electrode 2, and a separator 3, with the separator 3 disposed between the positive electrode 1 and the negative electrode 2. The electrode assembly can be a stacked structure, formed by alternately stacking the positive electrode 1, the separator 3, and the negative electrode 2. In other embodiments, the electrode assembly can also be a wound structure, formed by sequentially stacking and winding the positive electrode, the separator, and the negative electrode.

[0077] In some embodiments, the positive electrode 1 includes a positive current collector 101 and a positive active layer 102 disposed on at least one surface of the positive current collector 101.

[0078] In some embodiments, the positive current collector 101 may be made of aluminum foil or nickel foil, or any composite current collector disclosed in the prior art, such as, but not limited to, current collectors formed by combining the aforementioned conductive foil (aluminum foil or nickel foil, etc.) with a polymer substrate. The positive active layer 102 comprises a positive active material, which includes compounds that reversibly insert and deintercalate metal ions.

[0079] In some embodiments, the positive electrode active material may include lithium transition metal composite oxides, sodium transition metal composite oxides, etc. The lithium transition metal composite oxide contains lithium and at least one element selected from cobalt, manganese, and nickel.

[0080] In some embodiments, the positive electrode active material may include, but is not limited to, lithium cobalt oxide (LiCoO2), lithium nickel manganese cobalt ternary materials (NCM), lithium manganese oxide (LiMn2O4), and lithium nickel manganese oxide (LiNi). 0.5 Mn 1.5 At least one of lithium iron phosphate (LiFePO4) or lithium iron phosphate (LiFePO4).

[0081] In some embodiments, the negative electrode 2 includes a negative electrode current collector 201 and a negative electrode active material layer 202 disposed on at least one surface of the negative electrode current collector.

[0082] In some embodiments, the negative electrode current collector 201 can be at least one of copper foil, nickel foil, stainless steel foil, titanium foil, or carbon-based current collector, or any composite current collector disclosed in the prior art, such as, but not limited to, the current collector formed by combining the aforementioned conductive foil and polymer substrate. The negative electrode active material layer 202 includes a negative electrode material, which includes the graphite negative electrode material obtained after the above-described coke graphitization process.

[0083] The battery provided in this application has the advantages of high capacity, high initial efficiency, long cycle life, excellent rate performance, and low expansion. The battery can be a lithium-ion battery, a sodium-ion battery, a solid-state electrolyte battery, etc., and is not limited thereto.

[0084] The embodiments of this application will be further described below with reference to several examples. However, the embodiments of this application are not limited to the specific embodiments described below. Appropriate modifications and implementations can be made within the scope of protection.

[0085] Preparation of char

[0086] Example 1

[0087] The method for preparing coke in this embodiment includes the following steps:

[0088] (1) Medium-temperature coal tar pitch was extracted by solvent extraction and supercritical extraction to obtain the first carbon feedstock A. The total mass content of asphaltenes and resins in the first carbon feedstock A was Q1, which was 0.41%; the mass content of quinoline insolubles was Q2, which was 0.03%; the mass content of aromatic hydrocarbons was Q3, which was 90.12%; the mass content of saturated matter was Q4, which was 9.47%; and the density was 1.01 g / cm³. 3 .

[0089] (2) High-temperature coal tar pitch was solvent-extracted to obtain second carbon feedstock B. The total mass content of asphaltenes and resins in second carbon feedstock B was 27.89%, the quinoline insoluble matter (QI) content was 1.78%, the aromatic hydrocarbon content was 57.14%, the saturated content was 14.97%, and the density was 1.21 g / cm³. 3 .

[0090] (3) Add the first carbon raw material A to the first heating and stirring tank, the temperature of the stirring tank is 280℃; at the same time, add the second carbon raw material B to the second heating and stirring tank, the temperature of the stirring tank is 330℃;

[0091] (4) The heated first carbon raw material A and the second carbon raw material B are fed into a mixing and heating device at a mass ratio of 95:5. The stirring rate is V = 140 r / min, and the temperature is rapidly increased to 500℃. Then, the heating rate is increased to 10℃ / min, and the mixture is rapidly transported to a coking device for coking reaction. The temperature in the coking device is 520℃, the pressure is 0.28 MPa, and the coking time is 24 h. After coking, the coke is cut and discharged to obtain the coke. The polarized microstructure of the coke is shown in Figure 2.

[0092] Figure 2 is a polarizing microscope test image of the focal at different magnifications provided in Embodiment 1 of this application. As shown in Figure 2, the focal includes a matrix tissue and multiple spheroidal tissues embedded in the matrix tissue. In the polarized mirror image of a single focal particle after cross-section processing and magnification by 50 times, the area of ​​the spheroidal tissue accounts for 94.97%.

[0093] Example 2

[0094] The difference from Example 1 is:

[0095] The coking time in step (4) is 30 hours.

[0096] Example 3

[0097] The difference from Example 1 is:

[0098] The mixing ratio of the first carbon raw material A and the second carbon raw material B in step (4) is 80:20.

[0099] Example 4

[0100] The difference from Example 1 is:

[0101] The first carbon feedstock A in step (1) has a total mass content of 2.24% for asphaltene and resin, a quinoline insoluble matter (QI) content of 0.04%, an aromatic hydrocarbon content of 88.32%, a saturated content of 9.44%, and a density of 1.09 g / cm³. 3 .

[0102] Example 5

[0103] The difference from Example 1 is:

[0104] The second carbon raw material B in step (1) has a total content of asphaltene and resin, a content of 0.66% of quinoline insoluble matter (QI), a content of 48.79% of aromatic hydrocarbons, a saturated content of 8.83%, and a density of 1.24 g / cm3.

[0105] In step (3), the temperature of the mixing tank for the second carbon raw material B is 350℃;

[0106] The stirring rate in step (4) is 60 r / min and the coking temperature is 500℃.

[0107] Example 6

[0108] (1) Medium-temperature coal tar pitch was extracted by solvent extraction and supercritical extraction to obtain the first carbon feedstock A. The total mass content of asphaltenes and resins in the first carbon feedstock A was Q1, which was 0.40%; the mass content of quinoline insolubles was Q2, which was 0.03%; the mass content of aromatic hydrocarbons was Q3, which was 93.24%; the mass content of saturated matter was Q4, which was 6.63%; and the density was 1.03 g / cm³.3 .

[0109] (2) High-temperature coal tar pitch was extracted with a solvent to obtain second carbon feedstock B. The total mass content of asphaltenes and resins in second carbon feedstock B was 44.93%, the quinoline insoluble matter (QI) content was 1.91%, the aromatic hydrocarbon content was 40.62%, the saturated content was 14.45%, and the density was 1.22 g / cm³. 3 .

[0110] (3) Add the first carbon raw material A to the first heating and stirring tank, the temperature of the stirring tank is 260℃; at the same time, add the second carbon raw material B to the second heating and stirring tank, the temperature of the stirring tank is 350℃;

[0111] (4) The heated first carbon raw material A and the second carbon raw material B are fed into a mixing and heating device at a mass ratio of 95:5. The stirring rate is V = 150 r / min, and the temperature is rapidly increased to 505°C. Then, the heating rate is increased to 10°C / min, and the mixture is rapidly transported to a coking device for coking reaction. The temperature in the coking device is 515°C, the pressure is 0.28 MPa, and the coking time is 24 h. After coking, the coke is cut and discharged to obtain the coke.

[0112] Example 7

[0113] The difference from Example 6 is:

[0114] In step (4), the mixing ratio of the first carbon raw material A and the second carbon raw material B is 80:20; the temperature inside the coking unit is 495℃ and the coking time is 30h.

[0115] Figure 3 is a polarizing microscope test diagram of the focal length provided in Embodiment 7 of this application.

[0116] Example 8

[0117] The difference from Example 6 is:

[0118] In step (3), the temperature of the mixing tank for the second carbon feedstock B is 370℃;

[0119] In step (4), the mixing ratio of the first carbon raw material A and the second carbon raw material B is 85:15; the temperature inside the coking unit is 500℃ and the coking time is 28h.

[0120] Example 9

[0121] (1) Medium-temperature coal tar pitch was extracted by solvent extraction and supercritical extraction to obtain the first carbon feedstock A. The total mass content of asphaltenes and resins in the first carbon feedstock A, Q1, was 1.15%, the mass content of quinoline insolubles, Q2, was 0.04%, the mass content of aromatic hydrocarbons, Q3, was 88.46%, the mass content of saturated matter, Q4, was 10.39%, and the density was 1.04 g / cm³.3 .

[0122] (2) High-temperature coal tar pitch was extracted with a solvent to obtain second carbon feedstock B. The total mass content of asphaltenes and resins in second carbon feedstock B was 36.87%, the quinoline insoluble matter (QI) content was 1.67%, the aromatic hydrocarbon content was 50.27%, the saturated content was 12.86%, and the density was 1.19 g / cm³. 3 .

[0123] (3) Add the first carbon raw material A to the first heating and stirring tank, the temperature of the stirring tank is 270℃; at the same time, add the second carbon raw material B to the second heating and stirring tank, the temperature of the stirring tank is 380℃;

[0124] (4) The heated first carbon raw material A and the second carbon raw material B are fed into a mixing and heating device at a mass ratio of 90:10. The stirring rate is V = 145 r / min, and the temperature is rapidly increased to 500℃. Then, the heating rate is increased to 10℃ / min, and the mixture is rapidly transported to a coking device for coking reaction. The temperature in the coking device is 505℃, the pressure is 0.25 MPa, and the coking time is 25 h. After coking, the coke is cut and discharged to obtain the coke.

[0125] Example 10

[0126] The difference from Example 9 is:

[0127] In step (3), the temperature of the mixing tank for the second carbon raw material A is 290℃;

[0128] In step (4), the mixing ratio of the first carbon raw material A and the second carbon raw material B is 93:7, and the coking time is 28h.

[0129] Comparative Example 1

[0130] The difference from Example 1 is:

[0131] In step (4), the mass ratio of the first carbon raw material A and the second carbon raw material B is 65:35.

[0132] Comparative Example 2

[0133] The difference from Example 1 is:

[0134] Step 1 uses the first carbon raw material A and prepares coke as Comparative Example 2 through the same heating and coking process.

[0135] Comparative Example 3

[0136] The difference from Example 1 is:

[0137] Step 1 uses the second carbon raw material B and prepares coke as comparative example 3 through the same heating and coking process.

[0138] Preparation of negative electrode materials

[0139] The coke prepared in the above embodiments and comparative examples were subjected to graphitization treatment, specifically including the following steps:

[0140] The coke was crushed to a median particle size D50 of 11±1μm. The crushed material was then carbonized at 1150℃ and subsequently graphitized at 3000℃ for 3 hours. The resulting material was then dispersed and sieved to obtain a negative electrode material with a D50 of 11±1μm.

[0141] Test methods

[0142] (1) Test method for foam tissue type:

[0143] The coke samples were cross-sectioned, and the cross-sections of the polished coke samples were observed using a Carl Zeiss Axio Scope A1 polarizing microscope. Quantitative analysis of the polarized structure was performed at 200x magnification. During the test, the position of the polarizer was moved sequentially, and the tissue observed in the central area of ​​the microscope was classified according to YB / T77-2017 "Determination of Optical Structure of Coke".

[0144] (2) Test method for the proportion of Brooks-Taylor structures in spheroidal tissue of pyrolysis:

[0145] The char was treated at 1000°C for 3 hours under inert gas such as nitrogen, then cooled and subjected to cross-sectioning. The polished char samples were observed using a Carl Zeiss Axio Scope A1 polarizing microscope to determine the structural types of 200 globular tissues. The number of globular tissues with Brooks-Taylor structures was counted and their proportion was calculated.

[0146] (3) Test method for the size and area ratio of tissue type: The polarized tissue was observed and photographed at 50x magnification, and the size of the tissue under the field of view was measured by the scale function in the microscope software.

[0147] Methods for testing the size and area ratio of spheroidal tissues:

[0148] Size R of globular tissue: ① First, test the size of a single globular tissue -- use a software ruler to measure the longest and shortest diameters of the globular tissue, and take the average of the longest and shortest diameters as the calculated diameter; ② Under the field of view photograph, count the calculated diameters of all globular tissues, and take the average of the calculated diameters of all globular tissues as the size of the globular tissue, which is recorded as the average diameter R of the globular tissue.

[0149] Area percentage of globular tissue: The cross-section of a single globular tissue is circular or nearly circular. To facilitate area calculation, the area M of a single circle is calculated with R as the diameter, and then multiplied by the number of globular tissues in the field of view to obtain the sum of the areas of the total globular tissues, M. 球 Then M 球 The total area M of the field of view photograph 总 The ratio is the area percentage of spheroidal tissue.

[0150] The area percentage of matrix tissue: M represents the area of ​​spheroidal tissue removed from the field of view image. 球 The remaining area after that is the area M of the matrix tissue. 基 ,1-M 球 / M 总 This represents the area percentage of the matrix tissue.

[0151] The thickness of the matrix tissue was measured using software, specifically the longest distance L between two adjacent globular tissues in the field of view photograph. 长 With the shortest distance L 短 As shown in Figure 3 or Figure 4, take its average value L. o For thickness, L o =(L 长 +L 短 ) / 2; Count the number of adjacent spheroidal tissues to 50 groups, and take the average thickness data of these 50 groups as the thickness L of the matrix tissue.

[0152] Size of mosaic structures in matrix: Under 200x polarization, the diameters of at least 50 mosaic structures in the matrix are measured, and the average value is taken as the size of the mosaic structures in the matrix.

[0153] (4) Test method for ash content in coke:

[0154] Ash content was determined using a Sigma SGM.M8 / 10A muffle furnace in accordance with GB / T 2295-2008 "Method for Determination of Ash Content in Coking Solids".

[0155] (5) Test method for volatile components contained in coke:

[0156] Volatile matter was determined using a Sigma SGM.M8 / 10A muffle furnace in accordance with GB / T 2001-2013 "Analytical and Determination Methods for Coke Industry".

[0157] (6) Testing the orientation degree of the negative electrode material:

[0158] The orientation degree of the negative electrode material was obtained by using a Panaco X'pert PRO X-ray diffractometer from the Netherlands and referring to the method in GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries" by measuring the ratio of the peak area C004 of the (004) plane to the peak area C110 of the (110) plane of the negative electrode material particles by X-ray diffraction pattern.

[0159] (7) Testing of the graphitization degree of the negative electrode material:

[0160] The diffraction angle of the (002) crystal plane of the negative electrode material was determined by X-ray diffraction pattern using a Panaco X'pert PRO X-ray diffractometer from the Netherlands, referring to the method in GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries". The interlayer spacing d002 of the (002) crystal plane was calculated according to the Bragg formula, and the degree of graphitization was calculated using the Mering-Maire formula.

[0161] (8) Testing the true density of the negative electrode material:

[0162] The true density of the material was measured using an Anton Pacanta PENTAPYC 5200e true density meter. Applying Archimedes' principle (density = mass / volume) based on gas displacement, and utilizing Bohr's law (PV = nRT) under certain conditions for small-molecule inert gases, the true density was accurately measured, with units of g / cm³. 3 .

[0163] (9) Test method for median particle size of negative electrode materials:

[0164] The particle size distribution method was based on GB / T 19077-2016. The particle size distribution range of the negative electrode material was tested using a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK. The cumulative particle size distribution based on volume was determined by laser diffraction, and D50 represents the particle size corresponding to a cumulative particle size distribution percentage of 50%.

[0165] (10) Test method for rate performance of lithium-ion button half-cells:

[0166] The negative electrode materials prepared in each embodiment and comparative example were used as active materials. They were mixed in a mass ratio of active material: conductive carbon black: CMC: SBR = 95.3:1.5:1.4:1.8, and the mixture was coated onto copper foil using deionized water as a solvent. The coating surface density was 6.5 ± 0.1 mg / cm³. 2 After vacuum drying at 90℃, electrode sheets are obtained. The electrode sheets are then rolled to a compaction density of 1.50±0.02 g / cm³. 3Electrodes, lithium foil, electrolyte (1 mol / L LiPF6, ethylene carbonate EC: ethyl methyl carbonate EMC: dimethyl carbonate DMC = 1:1:1), and Celgard 2400 separator were assembled into a 2016-type coin cell. Charge-discharge tests were conducted on the coin cell at a current density of 0.1C within a charge-discharge range of 0.01V-5V to obtain the initial discharge specific capacity and initial coulombic efficiency (ICE) of the coin cell.

[0167] Coin cell half-cells were subjected to rate performance testing at 25±2℃ to obtain charge / discharge specific capacities and coulombic efficiencies at 0.1C, 0.2C, 1C, and 2C. The rate test conditions were: ① 0.1C discharge to 0.01V, constant voltage to 0.01C, 0.1C charge to 1.5V; ② 0.2C discharge to 0.01V, constant voltage to 0.01C, 0.2C charge to 1.5V; ③ 1C discharge to 0.01V, constant voltage to 0.01C, 0.2C charge to 1.5V; ④ 2C discharge to 0.01V, constant voltage to 0.01C, 0.2C charge to 1.5V. The 2C / 0.2C discharge capacity retention rate can be calculated by dividing the 2C discharge specific capacity by the 0.2C discharge specific capacity.

[0168] Table 1. Performance parameters of the coke and anode materials prepared in each embodiment and comparative example

[0169] Table 2. Performance parameters of the negative electrode materials and their batteries prepared in each embodiment and comparative example.

[0170] According to the embodiment data of this application, the raw materials formed by mixing the first and second carbon source raw materials in a controlled manner, and then rapidly heating them during coking, are conducive to forming coke with the desired structure. The area ratio of spheroidal structures in the coke is greater than or equal to 85%, indicating a high proportion of spheroidal structures in the coke. These spheroidal structures embedded in the matrix can be independent of each other. Compared with needle-shaped coke, spheroidal structures can enhance the isotropy of coke particles, which is beneficial for maintaining the isotropy of coke during processes such as granulation, carbonization, graphitization, and electrode preparation, reducing the formation of sheet-like or fibrous materials. Furthermore, this application controls the coke to meet the condition 5≤R / L≤30, which can effectively reduce the agglomeration of spheroidal structures by utilizing the matrix structure, thereby increasing the size of the spheroidal structures and the area ratio of spheroidal structures in the coke, and thus improving the isotropy of the coke. Due to the high isotropy of the coke, the negative electrode material can have both high specific capacity and excellent rate performance.

[0171] The orientation degree of the anode materials prepared by the coke in the examples was lower than that of Comparative Examples 1 and 2. This shows that after carbonization and graphitization, the graphite grains in the resulting anode materials maintained a high degree of isotropy, and the anode materials could possess both high capacity and good rate performance. In particular, Example 2 achieved a capacity of 354.9 mAh / g after graphitization, and maintained a high 2C / 0.2C capacity retention rate of 37.7%.

[0172] Compared to Example 1, Comparative Example 1 has a different structure because the mass ratio of the first carbon raw material A to the second carbon raw material B in Comparative Example 1 is 65:35. The amount of the first carbon raw material A added is too small, making it difficult to form a sufficient amount of spherical structure. The resulting spherical structure has a lower R... max / R min The size is too large, meaning that a large amount of non-spherical structure exists in the spherical structure, which leads to an increase in the orientation degree of the negative electrode material, and the capacity and rate capability of the negative electrode material are reduced compared with Example 1.

[0173] Compared to Example 1, Comparative Example 2 has a higher capacity, but its rate performance is worse. This is mainly because it cannot generate individual, isolated spherical structures. A large number of spherical structures merge into one to form a sheet-like structure. The average diameter of the spherical structures actually reflects the size of the sheet-like structure, resulting in a significant increase in diameter. The average thickness of the matrix structure is difficult to measure, and the rate performance of the negative electrode material is biased towards that of needle coke.

[0174] Compared to Example 1, Comparative Example 3 used a feedstock oil with higher contents of asphaltenes, gums, and quinoline insolubles. This facilitates the formation of a matrix structure composed of a single mosaic structure, resulting in a more disordered orientation of the coke microstructure and an increased number of grain boundaries between the coke microstructures. This makes it difficult for the carbon layers to achieve an ordered arrangement during graphitization, leading to a high degree of graphitization and consequently, fewer lithium storage sites. Although the rate performance of the anode materials is roughly comparable, the lower degree of graphitization results in a significant decrease in capacity.

[0175] Although this application discloses preferred embodiments as described above, it is not intended to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

Claims

1. A type of coke, characterized in that, The coke comprises a matrix tissue and multiple spheroidal tissues embedded within the matrix tissue; in a polarizing microscope image of a single coke particle after cross-section processing and magnification by 50x, the area of ​​the spheroidal tissues accounts for ≥85%; The average diameter of the spheroidal tissue is R μm, the average thickness of the matrix tissue between two adjacent spheroidal tissues is L μm, and the foam satisfies 5 ≤ ​​R / L ≤ 30.

2. The coke according to claim 1, characterized in that, The focal point satisfies: 5≤R / L≤26; or 5 ≤ R / L ≤ 20; or, R / L values ​​are 5, 6, 11, 16, 17, 19, 22, 26, 30, or any two values ​​within a range.

3. The coke according to claim 1, characterized in that, The focal point satisfies: 50≤R≤150; or, 50≤R≤130; or, The value of R is a range of 52, 63, 60, 88, 90, 111, 128, 130, 147, 150 or any two of these values.

4. The coke according to claim 1, characterized in that, The focal point satisfies: 3≤L≤30; or, 3≤L≤15; or, The value of L is a range of 3, 4, 5, 6, 11, 29, or any two values.

5. The coke according to claim 1, characterized in that, The focal point satisfies: The ratio R of the longest diameter to the shortest diameter of the spheroidal tissue max / R min It is 1.0 to 1.5; or, R max / R min It is 1.1 to 1.5; or, R max / R min The value is a range of 1.1, 1.2, 1.3, 1.4, 1.5 or any two values.

6. The coke according to claim 1, characterized in that, The focal point satisfies: The area of ​​the spheroidal tissue accounts for 85% to 95%; or, The area percentage of the spheroidal tissue is 85%, 87%, 88%, 92%, 93%, 94%, 95%, or any combination of two values.

7. The coke according to claim 1, characterized in that, The focal point satisfies: The area ratio of the matrix tissue is 5% to 15%, or, The area percentage of the matrix tissue is 5%, 6%, 7%, 8%, 10%, 12%, 13%, 15%, or any two of these values.

8. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The globular tissue includes Brooks-Taylor structures, wherein the number of Brooks-Taylor structures in the globular tissue is ≥90%; (2) The matrix structure includes a mosaic structure with a size of 1.0 μm to 2.8 μm.

9. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The ash content of the coke at 950℃ is ≤0.3%; (2) The volatile matter content of the coke at 900℃ is ≤8.5% by mass.

10. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The coke also includes doping elements, which include at least one of iron, nickel, aluminum, calcium, vanadium, cobalt, zinc, manganese, sodium, potassium, copper, chromium, magnesium and silicon; (2) The coke also includes doping elements, and the mass content of any one of the doping elements in the coke is ≤100ppm.

11. A negative electrode material, characterized in that, The negative electrode material includes the negative electrode material obtained by graphitization of coke according to any one of claims 1 to 10.

12. The negative electrode material according to claim 11, characterized in that, The negative electrode material satisfies at least one of the following characteristics: (1) The orientation degree OI of the negative electrode material is 0.8 to 1.1; (2) The graphitization degree of the negative electrode material is 92% to 95%.

13. The negative electrode material according to claim 11, characterized in that, The negative electrode material satisfies at least one of the following characteristics: (1) The median particle size of the negative electrode material is 10 μm to 20 μm; (2) The true density of the negative electrode material is 2.15 g / cm³. 3 ~2.28g / cm 3 ; (3) The true density of the negative electrode material is 2.20 g / cm³. 3 ~2.28g / cm 3 .

14. The negative electrode material according to claim 11, characterized in that, The method for preparing the negative electrode material includes: pulverizing the coke, performing carbonization treatment and graphitization treatment to obtain the negative electrode material.

15. A battery, characterized in that, The battery includes the negative electrode material according to any one of claims 11 to 14.

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