Coke, negative electrode material and battery

Abstract

Provided in the present application are coke, a negative electrode material and a battery. The coke has pores, the specific surface area of the coke is S m2 / g, and the tap density of the coke is T g / cm3; the coke is tested by means of Raman mapping, and after fitting, an obtained test spectrum has a first carbon characteristic peak at 1200±10cm-1 with a peak area of I1, a second carbon characteristic peak within the range of 1350cm-1-1380cm-1 with a peak area of I2, a third carbon characteristic peak within the range of 1460cm-1-1530cm-1 with a peak area of I3, and a fourth carbon characteristic peak at 1580cm-1±10cm-1 with a peak area of I4, wherein R=I1 / (I1+I2+13+I4); and the coke meets 90≤T / [(S×R)^5+R^3]≤1000.

Description

Coke, negative electrode materials, batteries

[0001] This application claims priority to Chinese patent application 202510378747.9, filed on March 27, 2025. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of negative electrode material technology, specifically to coke, negative electrode materials, and batteries. Background Technology

[0003] 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 electrode materials 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.

[0004] As crude oil becomes increasingly heavy, the quality of coke feedstock is decreasing. Raw coke feedstock is difficult to fully develop under conventional coking conditions, resulting in smaller aromatic lamellae, more residual volatiles, and structural defects. This significantly impacts the graphitization process, leading to poor compaction density and specific capacity of graphitized products, which cannot meet the demand for high-energy-density anode materials.

[0005] To meet the comprehensive performance requirements of artificial graphite anode materials, improving the quality of coke raw materials, reducing the production cost of graphite anode materials, and increasing the capacity of graphite anode materials are still problems that need to be solved. Summary of the Invention

[0006] This application provides coke, anode materials, and batteries. The amorphous carbon content in the coke is reduced, the degree of order in its microstructure is improved, the internal structural defects of the coke are reduced, and the structural strength is improved, which is beneficial to improving the capacity and rate performance of the graphite anode materials prepared from the coke.

[0007] In a first aspect, this application provides a coke having pores, and the specific surface area of ​​the coke is S m. 2 / g, tap density is T g / cm³ 3 ;

[0008] The test image obtained by Raman plane scanning and fitting was located at 1200±10cm. -1 It has the first carbon characteristic peak and the peak area is I1, at 1350 cm⁻¹. -1 ~1380cm -1 It has a second carbon characteristic peak with a peak area of ​​I2 within the range, at 1460 cm⁻¹ -1 ~1530cm -1 It has a third carbon characteristic peak with a peak area of ​​I3 within the range, at 1580 cm⁻¹. -1 ±10cm -1 The fourth carbon characteristic peak is located at the point with a peak area of ​​I4, and R = I1 / (I1+I2+I3+I4);

[0009] The foci satisfy: 90≤T / [(S×R)^5+R^3]≤1000.

[0010] Secondly, this application provides a negative electrode material, which includes the graphite material prepared by coking as described in the first aspect.

[0011] Thirdly, this application provides a battery comprising the aforementioned negative electrode material.

[0012] The technical solution of this application has at least the following beneficial effects:

[0013] The coke provided in this application has a tap density of T g / cm³. 3 The higher the tap density, the smoother the surface of the coke, which can improve the compaction density and specific capacity of the graphite anode material obtained from the coke; the specific surface area of ​​the coke is S m 2 The smaller the specific surface area of ​​the coke, the fewer the internal pores and internal defects. The R value of the coke, measured by Raman spectroscopy, can characterize the surface defects of the coke, mainly the degree of defects in amorphous carbon. The lower the content of amorphous carbon in the coke, the better it is for improving the graphitization degree of the graphite anode material. With the reduction of surface and internal defects in the coke, the tap density is higher. At the same time, the coke of this application has pores, that is, an appropriate degree of defect can provide more lithium-ion channels, promoting the migration and transport of lithium ions in the material. This application controls the coke to satisfy 90≤T / [(S×R)^5+R^3]≤1000, which can achieve a balance between the tap density and the degree of defect in the coke. The structure of the coke is more compact and ordered, which can reduce the internal and surface defects of the coke, improve the graphitization degree of the graphite anode material obtained by coke graphitization treatment, and improve the specific capacity, tap density and rate performance of the graphite anode material. Attached Figure Description

[0014] Figure 1 is a schematic diagram of the discharge state of the battery provided in an embodiment of this application.

[0015] Figure 2 is the Raman spectrum of the raw coke provided in Example 1 of this application.

[0016] Figure 3 shows the Raman spectrum of the joule obtained in Example 1 of this application. 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] Based on this, in a first aspect, this application provides a coke having pores, and the specific surface area of ​​the coke is S m. 2 / g, tap density is T g / cm³ 3 ;

[0019] The test image obtained by Raman plane scanning and fitting was located at 1200±10cm. -1 It has the first carbon characteristic peak and the peak area is I1, at 1350 cm⁻¹. -1 ~1380cm -1 It has a second carbon characteristic peak with a peak area of ​​I2 within the range, at 1460 cm⁻¹ -1 ~1530cm -1 It has a third carbon characteristic peak with a peak area of ​​I3 within the range, at 1580 cm⁻¹. -1 ±10cm -1 The fourth carbon characteristic peak is located at the point with a peak area of ​​I4, and R = I1 / (I1+I2+I3+I4);

[0020] The foci satisfy: 90≤T / [(S×R)^5+R^3]≤1000.

[0021] In this application, I1, I2, I3, and I4 correspond to the areas of different carbon characteristic peaks in the Raman spectrum, used to characterize different types of carbon structures and defects in the coke. The first carbon characteristic peak is located at 1200±10 cm⁻¹. -1 At this point, it corresponds to defects and disordered structures in the coke, especially sp. 3 The presence of hybrid carbon atoms. I1 is used to quantitatively analyze the degree of defects in materials. The second carbon characteristic peak is located at 1350 cm⁻¹. -1 ~1380cm -1 Within the range, it corresponds to sp in the focal length. 2 Defects in hybrid carbon atoms, such as point defects and interlayer defects at the boundaries of graphite layers or within graphite sheets. I₂ is used to quantitatively analyze the amount of these defects. The third carbon characteristic peak is located at 1460 cm⁻¹. -1 ~1530cm -1Within this range, it corresponds to the vibrations of aliphatic carbons and grain boundary defects in the char, reflecting the content of non-graphitized carbon and the complexity of the structure inside the material. I3 is used to quantitatively analyze the degree of grain boundary defects or vacancy defects inside it. The fourth carbon characteristic peak is located at 1580 cm⁻¹. -1 ±10cm -1 At that point, it corresponds to sp in the focal plane. 2 The in-plane vibrations of hybrid carbon atoms represent the ordered graphite structure in the material, i.e., sp 2 The content of hybrid carbon. I4 is used for quantitative analysis of the amount of ordered graphite structure and is an important indicator for measuring the degree of graphitization of materials.

[0022] R = I1 / (I1+I2+I3+I4), where R represents the surface defect ratio, used to characterize the degree of surface defects in coke, especially the content of amorphous carbon structures. A higher R value indicates more defects or amorphous carbon in the material. These defects can provide channels for rapid lithium-ion transport, which is beneficial for improving the rate performance of the material. However, too many defects will reduce the compaction density and structural stability of the material, leading to a decrease in electrochemical performance (such as capacity and cycle life). R^3 indicates that the surface defect ratio R is raised to the cube, which also increases the influence of R on the final calculation results.

[0023] (S×R)^5 represents multiplying the specific surface area S of the coke and the surface defect ratio R by the fifth power, thus increasing the influence of these two parameters.

[0024] In existing technologies, a higher tap density of coke indicates smaller gaps between material particles, which helps improve the battery's compaction density and thus enhances its overall energy density. Simultaneously, a high tap density typically indicates a denser material surface, helping to reduce surface defects. A higher specific surface area of ​​coke indicates more porosity, providing more sites for charge storage. However, a high specific surface area also increases the contact area between the material and the electrolyte, exacerbating side reactions and affecting the battery's initial coulombic efficiency and cycle stability.

[0025] The formula T / [(S×R)^5+R^3] is a dimensionless value calculated by dividing the tap density T by [(S×R)^5+R^3]. This ratio comprehensively considers the relationship between the tap density of the coke and the porosity and surface defect degree.

[0026] The coke provided in this application has a tap density of T g / cm³. 3 The higher the tap density, the smoother the surface of the coke, which can improve the compaction density and specific capacity of the graphite anode material obtained from the coke; the specific surface area of ​​the coke is S m 2 / g, the smaller the specific surface area of ​​the coke, the fewer the internal pores and internal defects. The R value of the coke, measured by Raman spectroscopy, can characterize the surface defects of the coke, mainly the degree of defects in amorphous carbon. The lower the content of amorphous carbon in the coke, the better it is for improving the graphitization degree of the graphite anode material. As the surface and internal defects of the coke decrease, the tap density increases. However, an appropriate degree of defect can provide more lithium-ion channels, promoting the migration and transport of lithium ions within the material. This application controls the coke to satisfy 90≤T / [(S×R)^5+R^3]≤1000, which can achieve a balance between the tap density and the degree of defect of the coke. The structure of the coke is more compact and ordered, which can reduce the internal and surface defects of the coke, improve the graphitization degree of the graphite anode material obtained by graphitization treatment of the coke, and improve the specific capacity, tap density and rate performance of the graphite anode material.

[0027] If T / [(S×R)^5+R^3]<90, it indicates that there are too many specific surface areas and defects in the coke, resulting in excessive specific surface areas and defects in the graphite anode material obtained after graphitization treatment of the coke. Excessive defects and large specific surface areas will increase the side reactions between the material and the electrolyte, resulting in lower capacity and initial coulombic efficiency of the graphite anode material, and also impairing the cycle stability and storage performance of the graphite anode material.

[0028] If T / [(S×R)^5+R^3]>1000, although the coke has a high tap density and fewer surface defects, the coke is too dense, reducing the porosity and lithium-ion transport channels. This results in poor kinetic performance of the graphite anode material obtained by graphitizing the coke, thus affecting the rate performance and charging speed of the battery.

[0029] In some embodiments, the coke can be used to prepare anode materials, for example, by graphitization to prepare graphite anode materials, or directly as an additive in anode materials.

[0030] In some implementations, T / [(S×R)^5+R^3] can specifically be 90, 100, 200, 300, 400, 550, 670, 880, 920, 980, 1000 or any value between 90 and 1000, and is not limited here.

[0031] In some implementations, R = I1 / (I1+I2+I3+I4), 0.1≤R≤0.22, and the specific value of R can be 0.1, 0.12, 0.13, 0.15, 0.17, 0.19, 0.198, 0.2, 0.22, or any value between 0.1 and 0.22, without limitation here. Wherein, I1 is the peak area of ​​the first carbon characteristic peak, and I1 can reflect the in-plane defects of the graphite-like layers in the coke, as well as sp... 3Hybridized carbon content. I2 is the peak area of ​​the second carbon characteristic peak, also known as the D peak. I2 can reflect interlayer defects in graphite-like lamellar layers in coke. I3 is the peak area of ​​the third carbon characteristic peak. I3 can reflect impurities in coke (especially polycyclic aromatic hydrocarbons). 3 The content of carbon-carbon bonds (I3) can indirectly reflect the degree of grain boundary defects or vacancy defects within the coke. I4 is the peak area of ​​the fourth carbon characteristic peak, also known as the G peak (ideal graphite peak), which can reflect the sp content within the coke. 2 The in-plane vibrations of hybrid carbon atoms, I4, can reflect the content of ordered graphite structure within the coke. By controlling the R value within the above range, this application can reduce the content of carbon with defective structures within the coke, improve the structural order of the coke, reduce in-plane defects in the coke, reduce the specific surface area of ​​the graphite anode material obtained from the coke after graphitization treatment, reduce side reactions between the graphite anode material and the electrolyte, and improve the first coulombic efficiency of the graphite anode material.

[0032] In some embodiments, the ratio K1 between the full width at half maximum (FWHM) of the first carbon characteristic peak and the FWHM of the fourth carbon characteristic peak is 1.84 to 2.99. Specifically, K1 can be any value between 1.84, 1.91, 1.95, 1.98, 2.01, 2.04, 2.08, 2.09, 2.99, or 1.84 to 2.99, and is not limited thereto. The FWHM ratio K1 between the first and fourth carbon characteristic peaks can be used to represent sp. 3 When the degree of disorder of hybrid carbon and amorphous carbon is within the above range, it indicates that the coke has removed more alkyl side chains, reducing the steric hindrance between coke layers. This is conducive to the deposition of more and larger aromatic hydrocarbon sheets, thereby increasing the capacity of the coke-based anode material.

[0033] In some embodiments, the ratio K2 between the half-width at half maximum (WHM) of the second carbon characteristic peak and the half-width at half-maximum (WHM) of the fourth carbon characteristic peak is 1.16 to 1.76. Specifically, K2 can be any value between 1.16, 1.46, 1.48, 1.56, 1.58, 1.61, 1.63, 1.65, 1.76, or 1.16 to 1.76, and is not limited here. The ratio K2 between the second and fourth carbon characteristic peaks can represent the degree of disorder between graphite-like layers. An increase in the second carbon characteristic peak of coke, with a higher peak height and narrower peak shape, results in a ratio within the range of 2.45 to 2.66. This indicates that the layered structure in the coke exhibits more interlayer defects. The increase in interlayer defects is mainly due to the breakage of alkane and weak bonds, exposing more cross-sections, which is beneficial for the formation and development of microcrystalline structures and can further improve the capacity and powder conductivity of the anode material obtained from coke.

[0034] In some embodiments, the ratio K3 between the half-width at half maximum (HWHM) of the third carbon characteristic peak and the half-width at half maximum (HWHM) of the fourth carbon characteristic peak is 0.76 to 2.63. Specifically, K3 can be any value between 0.76, 1.35, 1.50, 1.67, 1.82, 2.01, 2.25, 2.55, 2.63, or 0.76 to 2.63, and is not limited thereto. The HWHM ratio K3 between the third and fourth carbon characteristic peaks can be used to represent the degree of disorder at the grain boundaries of the carbon material. In the coke of this application, grain boundary defects are reduced, the HWHM increases, and the HWHM of the graphite peak decreases. The ratio is controlled within the range of 4.12 to 6.03, which is beneficial for improving the graphitization degree of the negative electrode material and reducing structural defects.

[0035] In some embodiments, 3.2 ≤ (I1+I2+I3) / I4 ≤ 5.16, specifically it can be 3.2, 3.5, 3.7, 3.9, 4.0, 4.2, 4.6, 4.8, 4.9, 5.1, 5.16 or any value within the above range, and is not limited herein. This application controls the ratio of (I1+I2+I3) / I4 within the above range, which is beneficial for reducing the content of disordered and defective structures within the coke, and for improving the specific capacity and first coulombic efficiency of the graphite anode material prepared from the coke.

[0036] In some embodiments, 0.28 ≤ I3 / (I1+I2+I3+I4) ≤ 0.45, specifically it can be 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45 or any value within the above range, and is not limited herein. By controlling I3 / (I1+I2+I3+I4) within the above range, this application can reduce the content of disordered carbon in the coke, increase the structural order of the coke, improve the structural strength of the graphite anode material, and improve the cycle stability of the graphite anode material.

[0037] In some embodiments, 0.23 ≤ I2 / (I1+I2+I3+I4) ≤ 0.34, specifically it can be 0.23, 0.25, 0.26, 0.27, 0.28, 0.30, 0.31, 0.32, 0.33, 0.34 or any value within the above range, and is not limited herein. The larger I2 is, the more defects there are in the coke. By controlling I2 / (I1+I2+I3+I4) within the above range, this application can reduce the content of carbon with defective structures in the coke, improve the structural order of the coke, reduce internal and surface defects in the coke, reduce the specific surface area of ​​the graphite anode material obtained by graphitization treatment of the coke, reduce side reactions between the graphite anode material and the electrolyte, and improve the first coulombic efficiency of the graphite anode material.

[0038] In some implementations, the specific surface area of ​​the coke is S m 2 / g, 0.5≤S≤2.6, specific surface area can specifically be 0.5m² 2 / g, 0.7m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.9m 2 / g, 2.0m 2 / g, 2.25m 2 / g, 2.5m 2 / g, 2.57m 2 / g, 2.6m 2 / g or any value within the above range, without limitation. This application controls the specific surface area of ​​the coke within the above range, reducing surface and internal defects in the coke, which is beneficial for reducing the specific surface area of ​​the graphite anode material prepared from the coke, and for improving the specific capacity and first coulombic efficiency of the graphite anode material. Preferably, 1.5 ≤ S ≤ 2.6.

[0039] In some embodiments, the tap density of the coke is T g / cm³. 3 0.3≤T≤1.8, the tap density can specifically be 0.3 g / cm³. 3 0.6g / cm 3 0.9g / cm 3 1.1g / cm 3 1.3g / cm 3 1.5g / cm 3 1.8g / cm 3 Or any value within the above range, without limitation. The higher the tap density of the coke, the higher the microscopic order of the coke, and the more uniform the orientation of the microstructure within the coke. This application controls the tap density of the coke within the above range, which is beneficial to improving the mechanical strength and energy density of the graphite anode material prepared from the coke. Preferably, 0.6≤T≤1.8.

[0040] In some embodiments, the true density of the joule is Q g / cm³. 3 1.6≤Q≤2.2, the true density can specifically be 1.6 g / cm³. 3 1.8g / cm 3 1.9g / cm 3 2.0g / cm 3 2.1g / cm 3 2.15g / cm 3 2.2g / cm 3 Or any value within the range mentioned above, without limitation. Controlling the true density of the coke within the above range in this application is beneficial for improving the energy density of the graphite anode material prepared from the coke and enhancing the cycle stability of the anode material. Preferably, 1.9 ≤ Q ≤ 2.2.

[0041] In some embodiments, the ash content in the coke is ≤0.5% by mass, specifically it can be 0.5%, 0.4%, 0.3%, 0.25%, 0.2%, 0.15%, 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.

[0042] In some embodiments, the volatile matter content in the coke is 0.8% to 7% by mass, specifically 0.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, etc., and is not limited thereto. In this application, controlling the volatile matter content in the coke is beneficial for increasing the true density of the negative electrode material obtained from the coke through graphitization treatment, 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. Preferably, the volatile matter content in the coke is 2% to 4% by mass.

[0043] In some embodiments, the mass content of magnetic material in the coke is 50 ppm to 300 ppm. Specifically, the magnetic material may include the following components: Fe < 200 ppm, Co < 10 ppm, Cu < 10 ppm, Ni < 15 ppm, Al < 200 ppm, Cr < 20 ppm, Zn < 20 ppm, Mg < 50 ppm, Mn < 16 ppm, Na < 300 ppm, K < 30 ppm, Ca < 300 ppm, Si < 50 ppm, V < 100 ppm. Excessive magnetic material content may interfere with electron transport paths, leading to increased internal resistance of the battery. This application controls the content of magnetic material in the coke, which is beneficial for controlling the content of magnetic material in the negative electrode material prepared from the coke, thus ensuring that the negative electrode material maintains good electronic conductivity.

[0044] In some embodiments, the F element content in the coke is 10 mg / kg to 30 mg / kg. Specifically, the F element content can be 10 mg / kg, 12.5 mg / kg, 15 mg / kg, 20 mg / kg, 22.7 mg / kg, 28 mg / kg, 30 mg / kg, or any value between them, and is not limited thereto. Controlling the F element content in the coke within the above range, this application can improve the powder conductivity of the coke.

[0045] Secondly, this application provides a method for preparing coke, comprising the following steps:

[0046] Step S10: Vacuum impregnation treatment is performed on the mixture of raw coke raw material and impregnating agent to obtain a composite material, wherein the impregnating agent includes liquid asphalt containing polytetrafluoroethylene powder and heavy oil slurry, and the mass content of volatile matter in the raw coke raw material is 15% to 18%.

[0047] Step S20: The composite is heated to 150℃~250℃ for low-temperature calcination treatment for 2h~4h, and then heated to 500℃~700℃ for high-temperature calcination treatment for 3h~8h, and then cooled to obtain the first calcination product.

[0048] Step S30: The product from the first calcination is heated to 700℃~800℃ and calcined for 5h~10h to obtain coke.

[0049] The coke preparation method provided in this application, despite the high volatile content and low degree of coking of the raw coke, allows for the removal of moisture and highly volatile components from the composite through the addition of polytetrafluoroethylene powder to the impregnating agent and a low-temperature calcination stage. During the high-temperature calcination stage, most of the raw coke continues to coke, and a large amount of volatile matter is removed. The impregnating agent reacts with organic matter and incompletely coked components in the raw coke via free radical reactions, forming stable CF bonds. This promotes the cross-linking of free aromatic molecules, and some fluorine is further incorporated into the carbon skeleton, enhancing the mechanical strength of the carbon skeleton structure. The calcination process ensures that the raw coke reacts fully with the impregnating agent. The coking reaction significantly reduces the volatile matter in the raw coke, decreases the steric hindrance between lamellar molecules, and increases the content of anisotropic structures. The first calcination product obtained after cooling is heated to the calcination temperature again. The higher calcination temperature allows the impregnating agent filled in and on the surface of the raw coke to be fully pre-carbonized, promoting cross-linking between lamellar molecules. The structure within the raw coke is reorganized, gradually transforming from a metastable crystalline phase to a polycrystalline phase. This repairs vacancies and defects within the raw coke, reduces amorphous carbon structures, improves the microscopic order of the coke, and increases the graphitization degree of the graphite anode material obtained from the coke through graphitization treatment. This enhances the specific capacity, compaction density, and rate performance of the graphite anode material.

[0050] The preparation method of this application is explained in detail below with reference to the embodiments:

[0051] Step S10: Vacuum impregnation treatment is performed on the mixture of raw coke and impregnating agent to obtain a composite material, wherein the impregnating agent includes liquid asphalt containing polytetrafluoroethylene powder and heavy oil slurry, and the mass content of volatile matter in the raw coke is 15% to 18%.

[0052] In some embodiments, the raw coke feedstock includes at least one of petroleum coke, pitch coke, mesophase spherical coke, and coal coke.

[0053] In some embodiments, the volatile matter content in the raw coke is 15% to 18% by mass, specifically 18%, 17%, 16%, 15% or any value between them, and is not limited here.

[0054] In some embodiments, the mass content of sulfur in the raw coke is ≤5%; specifically, it can be 5%, 4%, 3%, 2%, 1%, 0.5% or any value between them, and is not limited here.

[0055] In some embodiments, in a polarized light microscope image of a single raw coke particle after cross-section processing and magnification by 50x, the area ratio of the mosaic structure is ≤30%, and the area ratio of the mesophase spherical structure is ≤15%.

[0056] In some implementations, the particle size D50 of the raw coke is 100mm to 500mm, which can be crushed by coarse crushing equipment.

[0057] In some embodiments, the impregnating agent includes liquid bitumen containing polytetrafluoroethylene powder and heavy oil slurry. The heavy oil slurry is waste residue oil generated from industrial oil refining or coking, which has low procurement costs and extremely high economic benefits.

[0058] In some embodiments, the mass content of polytetrafluoroethylene powder in the impregnating agent is 0.1% to 5%, specifically 0.1%, 0.5%, 1%, 1.5%, 2%, 3%, 5% or any value between them, and is not limited herein.

[0059] In some embodiments, the mass ratio of liquid asphalt to heavy oil slurry in the impregnating agent is 10:(1-5), specifically 10:1, 10:2, 10:3, 10:4, 10:5, or any value between them, and is not limited herein. In this application, by controlling the mass ratio of liquid asphalt to heavy oil slurry and the amount of polytetrafluoroethylene powder added, it is beneficial to improve the isotropy of coke, so that the negative electrode material obtained from coke has both high specific capacity and excellent rate performance.

[0060] In some embodiments, polytetrafluoroethylene powder, liquid asphalt, and heavy oil slurry are mixed during heating and stirring to obtain an impregnating agent. The heating temperature is 60°C to 120°C, and the stirring time is 1 hour to 5 hours.

[0061] In some embodiments, polytetrafluoroethylene powder, liquid asphalt, and heavy slurry are mixed during heating and stirring at a stirring rate of 300 r / min to 1000 r / min. Specifically, the stirring rate can be 300 r / min, 400 r / min, 500 r / min, 600 r / min, 800 r / min, or 1000 r / min, or any value between them, and is not limited here.

[0062] This application enables the various components in the impregnating agent to be fully and evenly mixed by controlling the stirring rate, temperature and time during the stirring process.

[0063] In some embodiments, the mass ratio of the impregnating agent to the raw coke is 1:(30-50), specifically 1:30, 1:35, 1:40, 1:45, 1:50 or any value between them, which is not limited here.

[0064] In some embodiments, the temperature of the vacuum impregnation treatment is 60°C to 120°C; specifically, it can be 60°C, 70°C, 80°C, 100°C, 110°C, 115°C, 120°C or any value between them, and is not limited here.

[0065] In some embodiments, the vacuum impregnation treatment time is 10h to 30h, specifically 10h, 16h, 18h, 24h, 28h, 30h or any value between them, and is not limited here.

[0066] In some embodiments, the vacuum degree of the vacuum impregnation process is <0.2 Pa, specifically 0.199 Pa, 0.18 Pa, 0.15 Pa, 0.12 Pa, 0.1 Pa, 0.08 Pa, 0.05 Pa or 0.01 Pa, etc., or other values ​​within the above range, which are not limited here.

[0067] In this application, by controlling the temperature, time and vacuum degree of vacuum impregnation treatment, the impregnating agent can be fully filled into the pores of the raw coke. After subsequent calcination treatment, a chemical reaction occurs between the uncoked structure in the raw coke, the organic matter in the volatile matter, and the impregnating agent, thereby generating a new structure in the pores, which can improve the structural order of the coke and reduce defective structures.

[0068] Step S20: The composite is heated to 150℃~250℃ for low-temperature calcination treatment for 2h~4h, and then heated to 500℃~700℃ for high-temperature calcination treatment for 3h~8h, and then cooled to obtain the first calcination product.

[0069] In some embodiments, the specific temperature of the low-temperature calcination treatment can be 150°C, 160°C, 170°C, 180°C, 200°C, 210°C, 220°C, 230°C, 250°C or any value between them, and is not limited herein.

[0070] In some implementations, the specific time for low-temperature calcination treatment can be 2h, 2.5h, 3h, 3.5h, 4h or any value between them, and is not limited here.

[0071] In some embodiments, both the low-temperature calcination treatment and the high-temperature calcination treatment are carried out under a protective atmosphere, which includes at least one of nitrogen, helium, neon, and argon.

[0072] In some embodiments, the flow rate of the protective atmosphere is 50 mL / min to 300 mL / min, specifically 50 mL / min, 100 mL / min, 150 mL / min, 300 mL / min, or any value between them, and is not limited herein. Preferably, the flow rate of the protective atmosphere is 100 mL / min to 150 mL / min.

[0073] In some embodiments, the heating rate of the low-temperature calcination treatment is 5°C / min to 10°C / min, specifically 5°C / min, 8°C / min, 10°C / min or any value between them, and is not limited here.

[0074] In some embodiments, the calcination equipment may be at least one of a rotary kiln, roller kiln, tube furnace, and box furnace.

[0075] It should be noted that the low-temperature calcination stage can remove moisture and highly volatile components from the material, providing a basis for further reactions.

[0076] In some embodiments, the temperature of the high-temperature calcination treatment can be 500°C, 520°C, 550°C, 580°C, 600°C, 620°C, 630°C, 650°C, 700°C or any value between them, and is not limited here.

[0077] In some implementations, the specific time for high-temperature calcination treatment can be 3h, 5h, 6h, 7h, 8h or any value between them, and is not limited here.

[0078] In some embodiments, the heating rate of the high-temperature calcination treatment is 2℃ / min to 10℃ / min, specifically 2℃ / min, 5℃ / min, 8℃ / min, 10℃ / min or any value between them, and is not limited here.

[0079] It should be noted that during the high-temperature calcination stage, most of the raw coke in the raw coke continues to coke and a large amount of volatile matter is removed. The impregnating agent reacts with the organic matter and incompletely coked components in the raw coke with free radicals to form stable CF bonds, which promote the cross-linking of free aromatic molecules and cause aromatic condensation reactions, generating a large amount of gas. At the same time, the light alkanes attached to the aromatic lamellar skeleton are further removed with the escape of gas, reducing the volatile matter in the raw coke, increasing the anisotropic structure, and reducing amorphous carbon. In addition, high-temperature calcination can enhance the further doping of fluorine into the carbon skeleton, which can improve the mechanical strength of the carbon skeleton structure and reduce the adhesion index and heteroatom content.

[0080] Step S30: The product from the first calcination is heated to 700℃~800℃ and calcined for 5h~10h to obtain coke.

[0081] In some embodiments, calcination is carried out in a pure oxygen atmosphere, and by calcining the product of a primary calcination, the mechanical strength of the coke's structural network can be enhanced.

[0082] In some embodiments, the heating rate during calcination is 1℃ / min to 5℃ / min, specifically 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min or any value between them, and is not limited here.

[0083] In some embodiments, the calcination temperature is 700℃ to 800℃, specifically 700℃, 720℃, 750℃, 780℃, 790℃, 800℃ or any value between them, and is not limited here.

[0084] In some embodiments, the calcination time is 5h to 10h, specifically 5h, 6h, 8h, 9h, 10h or any value between them, and is not limited here.

[0085] As the coking reaction between the raw coke and the impregnating agent is completed during the first calcination process, the volatile matter in the raw coke is significantly reduced, the steric hindrance between lamellar molecules decreases, and the content of anisotropic structures increases. The material needs to be cooled to solidify the existing structure, and then heated again to the calcination temperature, where further structural changes occur within the raw coke. The higher calcination temperature allows the impregnating agent filling the raw coke and its surface to be fully pre-carbonized, promoting cross-linking between lamellar molecules, maintaining the stability of the raw coke structure and the reaction system, promoting the dehydrogenation condensation reaction of aromatics, and causing the structure within the raw coke to be reorganized, gradually transforming from a metastable crystalline phase to a polycrystalline phase. This repairs vacancies and defects within the raw coke, reduces amorphous carbon structures, and improves the microscopic order of the coke.

[0086] Thirdly, this application also provides a negative electrode material, which includes the graphite negative electrode material obtained by graphitizing the coke as described above.

[0087] 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, 1.1, or any value between them, without limitation. In this application, when the orientation degree of the negative electrode material is controlled within the above range, the graphite crystal structure can be arranged more orderly, the isotropy of the negative electrode material is high, the lithium-ion insertion / extraction rates are closer, the internal resistance of the negative electrode material can be reduced, and the negative electrode material has better cycle performance and rate performance.

[0088] 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%, 95%, or any value between them, and is not limited thereto. In this application, controlling the graphitization degree of the negative electrode material within the above range results in a more regular crystal structure, which is beneficial for improving lithium-ion transport efficiency and increasing the capacity retention rate of the negative electrode material during cycling.

[0089] 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 or any value between them, without limitation.

[0090] In some specific embodiments, the preparation method of the negative electrode material includes: crushing coke, performing carbonization and graphitization treatment to obtain the negative electrode material.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] Fourthly, this application also provides 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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).

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] Preparation of char

[0106] Example 1

[0107] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarized structure mainly of domain structure, mosaic structure area ratio of 20%, and mesophase spherical structure area ratio of 10%). It was crushed using a coarse crusher, and the particle size of the material was controlled to be 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature was 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reaction vessel at a mass ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0108] (2) The composite was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 550°C at 10°C / min and calcined at 550°C for 8 hours. The product was then cooled naturally to obtain the first calcined product.

[0109] (3) The product from the first calcination is heated to 800°C at 2°C / min, 99% oxygen is introduced, the gas flow rate is controlled at 100mL / min, and the temperature is maintained for 10h to obtain coke.

[0110] Figure 2 is the Raman spectrum of the raw coke provided in Example 1 of this application, and Figure 3 is the Raman spectrum of the coke prepared in Example 1 of this application. As shown in Figures 2 and 3, the peak areas of I2 and I4 are significantly increased.

[0111] Example 2

[0112] The difference from Example 1 is:

[0113] The high-temperature calcination treatment in step (2) is carried out at 600℃ for 6 hours.

[0114] Example 3

[0115] The difference from Example 1 is:

[0116] The high-temperature calcination treatment in step (2) is carried out at 700℃ for 6 hours.

[0117] Example 4

[0118] The difference from Example 1 is:

[0119] (1) Raw petroleum coke with a low degree of coking was selected as raw material (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, and 10% of mesophase spherical structure). It was crushed using a coarse crusher, and the particle size of the material was controlled to be 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 10:1, and 1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature was 80℃. After stirring for 3 h, the impregnated material was obtained. The impregnated material and raw coke powder were added to the reactor at a ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa.

[0120] Example 5

[0121] The difference from Example 1 is:

[0122] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 15 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0123] Example 6

[0124] The difference from Example 1 is:

[0125] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure). It was crushed using a coarse crusher, and the particle size of the material was controlled to be 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 2% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature was 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0126] Example 7

[0127] The difference from Example 1 is:

[0128] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 5% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0129] Example 8

[0130] The difference from Example 1 is:

[0131] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 0.1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0132] Example 9

[0133] The difference from Example 1 is:

[0134] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:30 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0135] Example 10

[0136] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 18%, sulfur content 4.26%, polarized structure mainly of domain structure, 30% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 2:1, and 0.1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 10 h. The temperature was heated to 60℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0137] (2) The composite was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 500°C at 10°C / min and calcined at 3 hours. The product was then cooled naturally to obtain the first calcined product.

[0138] (3) The product from the first calcination is heated to 700°C at 5°C / min, 99% oxygen is introduced, the gas flow rate is controlled at 100mL / min, and the temperature is maintained for 5h to obtain coke.

[0139] Example 11

[0140] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 15%, sulfur content 0.5%, polarized structure mainly of domain structure, 5% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 6:1, and 0.3% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 25 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0141] (2) The composite was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 520°C at 5°C / min and calcined at 5°C / min for 6 hours. The product was then cooled naturally to obtain the first calcined product.

[0142] (3) The product from the first calcination was heated to 740°C at 2°C / min, 99% oxygen was introduced, the gas flow rate was controlled at 100 mL / min, and the temperature was maintained for 10 h to obtain coke.

[0143] Example 12

[0144] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 15.93%, sulfur content 3.5%, polarization structure mainly of domain structure, 25% of mosaic structure, 15% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 8:1, and 0.6% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:42 and impregnated for 20 h. The temperature was heated to 120℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0145] (2) The composite was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 650°C at 10°C / min and calcined at 10°C / min for 10 hours before being naturally cooled and removed to obtain the first calcined product.

[0146] (3) The product from the first calcination was heated to 800°C at 2°C / min, 99% oxygen was introduced, the gas flow rate was controlled at 100 mL / min, and the temperature was maintained for 4 hours to obtain coke.

[0147] Example 13

[0148] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 15.04%, sulfur content 1.1%, polarization structure mainly of domain structure, 8% of mosaic structure, 19% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 7:1, and 0.1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:45 and impregnated for 20 h. The temperature was heated to 120℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0149] (2) The composite was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 530°C at 5°C / min and calcined at 5°C / min for 8 hours. The product was then cooled naturally to obtain the first calcined product.

[0150] (3) The product from the first calcination was heated to 800°C at 2°C / min, 99% oxygen was introduced, the gas flow rate was controlled at 100 mL / min, and the temperature was maintained for 7 h to obtain coke.

[0151] Example 14

[0152] The difference from Example 1 is:

[0153] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 17.93%, sulfur content 4.5%, polarization structure mainly of domain structure, 16.8% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and 1% PTFE powder (sieved through 325 mesh) was added. The stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:35 and impregnated for 20 h. The temperature was heated to 120℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0154] (2) The complex was placed in a crucible and calcined at 200°C for 2 hours under an argon atmosphere with a gas flow rate of 100 mL / min and a heating rate of 10°C / min. Then, the temperature was increased to 600°C at 10°C / min and calcined at 6 hours. The product was then cooled naturally to obtain the first calcined product.

[0155] (3) The product from the first calcination was heated to 750°C at 2°C / min, 99% oxygen was introduced, the gas flow rate was controlled at 100 mL / min, and the temperature was maintained for 7 h to obtain coke.

[0156] Comparative Example 1

[0157] Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, and 10% of mesophase spherical structure). It was crushed using a coarse crusher to control the particle size to 100mm. No further processing was performed.

[0158] Comparative Example 2

[0159] The difference from Example 1 is:

[0160] (2) The composite was placed in a crucible, and under an argon atmosphere, the gas flow rate was controlled at 100 mL / min and the heating rate was controlled at 10 °C / min. The temperature was raised to 550 °C and calcined for 8 hours. After natural cooling, the product was taken out to obtain the first calcination product.

[0161] Comparative Example 3

[0162] The difference from Example 1 is:

[0163] (2) The composite was placed in a crucible, and under an argon atmosphere, the gas flow rate was controlled at 100 mL / min and the heating rate was controlled at 10 °C / min. The mixture was heated to 200 °C and calcined for 2 hours. After natural cooling, the product was removed to obtain the first calcined product.

[0164] Comparative Example 4

[0165] The difference from Example 1 is:

[0166] Step (3) was not performed.

[0167] Comparative Example 5

[0168] The difference from Example 1 is:

[0169] (1) Petroleum coke with a low degree of coking was selected as raw coke (volatile matter 16.72%, sulfur content 3.26%, polarization structure mainly of domain structure, 20% of mosaic structure, 10% of mesophase spherical structure), and crushed using a coarse crusher to control the particle size to 100 mm. Low-temperature liquid asphalt and residual oil were mixed at a ratio of 5:1, and the stirring speed was set to 800 r / min and the temperature to 80℃. After stirring for 3 h, an impregnating agent was obtained. The impregnating agent and raw coke were added to the reactor at a mass ratio of 1:50 and impregnated for 20 h. The temperature was heated to 100℃, and the vacuum degree of the vacuum impregnation process was <0.1 Pa to obtain the composite.

[0170] Preparation of negative electrode materials

[0171] The coke prepared in the above embodiments and comparative examples were subjected to graphitization treatment, specifically including the following steps:

[0172] The coke was adjusted to a median particle size D50 of 10±2μm and fed into a roller kiln for carbonization at 1200℃ for 14h. Then it was fed into a graphitization furnace for high-temperature graphitization at 3000℃ for 10h. The resulting material was then broken up and screened to obtain graphite anode material.

[0173] Test methods

[0174] (1) Particle size testing of raw coke, coke, and graphite anode material:

[0175] The particle size distribution test method is in accordance with GB / T 24533-2019: During testing, take an appropriate amount of sample, pour it into pure water, and ultrasonically disperse it evenly. Then, add surfactant dropwise according to a ratio of sample:surfactant = 1g:1 drop, stir evenly, and then test. The particle size distribution range of the negative electrode material is tested using a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd. (UK). The cumulative particle size distribution based on volume is measured using laser diffraction. D50 represents the particle size corresponding to a cumulative volume distribution percentage of 50%.

[0176] (2) Test method for tap density of raw coke, coke and graphite anode material: The tap density of the material was tested using a GeoPyc 1365 tap density meter. The material was placed in the sample chamber of the tap density meter, weighed at 5.00g ± 0.01g, and a sample tube with a diameter of 19.1mm was used. The sample was rotated and vibrated for 3 revolutions under a pressure of 108N. The volume of the sample was recorded after 1000 vibrations. The tap density can be calculated according to the mass-volume ratio.

[0177] (3) Specific surface area testing of raw coke, coke, and graphite anode material:

[0178] The specific surface area of ​​the material was tested using a TriStar 3000 & 3020 Micrometer Analyzer. Referring to GB / T19587-2017 "Determination of Specific Surface Area / Pore Size Distribution of Solid Substances by Gas Adsorption BET Method", the specific surface area / pore size distribution of the material was tested: a dry micrometer tube was taken, and 1 / 2 to 2 / 3 of the volume of the material in the micrometer tube bulb was weighed; degassing treatment (removal of moisture or impurities) was required before testing. Degassing could be performed using vacuum heating or nitrogen purging (vacuum heating method: set the degassing temperature to 300℃, degassing time to 1 hour; after degassing, the tube should be placed in a cooling tank or an external micrometer tube rack for cooling for 20 minutes). After 5-10 seconds of backfilling with gas (depending on the situation, to avoid sample ejection and sticking to the side wall of the sample tube), the sample tube is then disassembled, and the sample tube is quickly plugged with a rubber stopper before proceeding with subsequent tests. For the nitrogen removal purging method: set the degassing temperature to 300℃ and the degassing time to 1 hour. After purging, place the sample in a cooling tank or on an external specific surface area tube holder for 20 minutes before quickly removing the rubber stopper and the degassing needle. Then quickly plug the rubber stopper again to prevent air from entering. The determination is performed according to the instruction manual of the specific surface area / pore size analyzer. At constant temperature and low temperature, the amount of gas adsorbed on the solid surface at different relative pressures is measured. Based on the Brownnor-Etter-Taylor adsorption theory and its formula (BET formula), the amount of monolayer adsorption of the sample is calculated, thereby calculating the specific surface area of ​​the material.

[0179] (4) True density test of raw coke, coke and graphite anode material:

[0180] The true density was tested using a Beijing Bestech / Anton Pacanta 3H-2000TD / 5200e true density meter, following the standard GB / T 214-2007: Helium gas with a purity higher than 99.9% was used; the sample cell was filled with at least 2 / 3 of its volume, and the cell was gently vibrated until the inner surface of the cell was highly stable. The sample mass was then accurately weighed to an accuracy of 0.0001 g. The determination was performed according to the instruction manual of the true density meter.

[0181] (5) Test methods for raw coke, volatile matter and ash content in coke:

[0182] The volatile matter was determined at 900℃ using a Sigma SGM.M8 / 10A muffle furnace according to GB / T 2001-2013 "Analytical Determination Methods for Coke Industry". Before the test, the boat was placed in the muffle furnace and heated to constant weight for 15 min. Then, a sample of m = 1 ± 0.0050 g was accurately weighed, spread evenly on the bottom of the boat, and weighed. The boat containing the sample was placed in the 900℃ muffle furnace, covered, and heated for 7 min. The boat was removed using crucible tongs, cooled at room temperature for 5 min, and then transferred to a desiccator to cool to room temperature for 20 min. The mass of the sample after constant weight was recorded as m2. The volatile matter was then calculated as (m1 - m2) / m × 100.

[0183] Ash content was determined at 1200℃ according to SH / T 0029-1990 "Determination of Ash Content in Petroleum Coke". Before testing, the boat was placed in a muffle furnace and heated to constant weight for 15 minutes, then weighed and recorded as mass m1. Then, a sample of m = 1 ± 0.0050 g was accurately weighed and spread evenly at the bottom of the boat. The boat containing the sample was placed in a muffle furnace at 1200℃ and heated for 3 hours. The boat was removed using crucible tongs, cooled at room temperature for 5 minutes, and then transferred to a desiccator to cool to room temperature for 20 minutes. The mass of the sample after constant weight was recorded as m2. The ash content was then calculated as (m2 - m1) / m × 100.

[0184] (6) Raman test method:

[0185] The test was performed using an XPLORA laser confocal Raman spectrometer. A small amount of sample (approximately 1g) was placed on a glass slide and flattened using a spatula. After placing the slide on the stage, the sample was focused clearly using a 50x objective lens. Thirty sample points were selected evenly. The laser was set to 532nm, the laser power to 0.01mW, the exposure time to 5s, and the number of cycles to 1. The test results of the 30 sampling points were averaged to obtain an average test curve. This curve was imported into Labspec 6. The "Processing" option was selected, and "Baseline Calibration" was clicked. In the pop-up baseline correction window, the baseline was selected and subtracted. The spectrum after baseline subtraction showed a Raman shift of 1200±10cm. -1 (First carbon characteristic peak), 1350–1380 cm⁻¹ -1 (Second carbon characteristic peak), 1460–1530 cm⁻¹ -1 (Third carbon characteristic peak) and 1580 cm⁻¹ -1 ±10cm -1 Search for peaks within the range of (fourth carbon characteristic peak). In the peak search options, adjust the peak search threshold to 5-30% and set the interval to 3-10 cm. -1 Between them, peak fitting analysis was performed using the asymmetric Gaussian Lorentz function, with the standard error controlled to be ≤5.0. The software automatically calculated the peak areas of each fitted characteristic peak, namely I1, I2, I3, and I4.

[0186] (7) Test of the mass content of magnetic materials in the coke:

[0187] Weigh 200±5g of sample into a 500ml wide-mouth plastic bottle. Add a cleaned magnetic rod and 300ml of anhydrous ethanol to the bottle. Cap the bottle and align it on an instrument for 30 minutes. Use the magnetic rod to adsorb magnetic metal elements such as iron, nickel, chromium, and zinc from the material. Open the cap and place a cleaned conical flask mouth-to-mouth with the wide-mouth bottle. Use another magnetic rod outside the wide-mouth bottle to transfer the magnetic rod from the wide-mouth bottle to the conical flask. Clean the non-magnetic material remaining on the magnetic rod inside the conical flask. Add 6ml of hydrochloric acid and 2ml of nitric acid. Heat on a hot plate for about 30 minutes. After filtration and volume adjustment, use inductively coupled plasma optical emission spectrometry (ICP-OES) to detect the content of magnetic substances.

[0188] (8) Test of the mass content of fluorine in coke.

[0189] According to GB / T 40111-2021, the sample is injected into a high-temperature combustion tube. The sample is burned under high-temperature, oxygen-rich, and hydrolytic conditions. The gases produced during combustion are collected in an absorption tube containing an absorbent liquid. Inside the absorption tube, the oxygen halide (HF) produced during combustion generates halide ions (F₂O₃) in the absorbent liquid. - The fluoride ion analyzer (BFG-810) automatically injects a quantitative amount of the absorption solution into the chromatography unit via the injection valve, detecting halogen ions (F...). - The sample is separated by a separation column and detected by a detector. The fluorine content of the sample can be obtained by the external standard method and expressed as a mass fraction.

[0190] (9) Testing the orientation degree of the negative electrode material:

[0191] The graphite anode material d002 and graphitization degree were tested using a Panaco X'pert PRO X-ray diffractometer from the Netherlands, in accordance with GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries". Silicon was added as an internal standard and 30% was added to the graphite. The sample and silicon powder in the mortar were ground back and forth with a pestle to make them evenly mixed. The grinding time was 3 minutes. After grinding, the sample was scraped with a glass slide and poured into the groove of the glass sample holder. It was then pressed and smoothed with a glass slide (care should be taken not to press too hard to avoid stress orientation of the sample). XRD was then tested with a scan rate of 0.138213° / s, a step size of 0.0131303°, and a test range of 10°-35°. The ratio of the peak area C004 of the (004) plane to the peak area C110 of the (110) plane of the anode material particles was determined by X-ray diffraction pattern.

[0192] (10) Testing of the graphitization degree of the negative electrode material:

[0193] The X'pert PRO X-ray diffractometer of the Dutch Panaco was used. The method in GB / T 24533-2019 "Graphite Anode Materials for Lithium-ion Batteries" was used, that is, the same method as (9) was used. The diffraction angle of the (002) crystal plane of the anode material was determined by X-ray diffraction pattern. The interlayer spacing d002 of the (002) crystal plane was calculated according to the Bragg formula. The degree of graphitization was calculated using the Mering-Maire formula.

[0194] (11) Test method for rate performance of lithium-ion button half-cells:

[0195] The negative electrode materials prepared in each embodiment and comparative example were used as active materials. The graphite negative electrode materials, carboxymethyl cellulose (CMC), conductive carbon black (SP), and styrene-butadiene rubber (SBR) prepared in the embodiments and comparative examples were mixed uniformly in a mass ratio of 95:1.5:1.5:2. The resulting slurry was prepared into a honey-like paste, uniformly coated onto copper foil, and vacuum dried at 130°C to obtain an electrode sheet. The electrode sheet, lithium sheet, 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. The coin cell was charged and discharged 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.

[0196] 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.

[0197] The test results are detailed in Tables 1 and 2:

[0198] Table 1. Test results of physicochemical properties of the examples and comparative examples.

[0199] Table 2. Test results of physicochemical and electrochemical properties of the examples and comparative examples

[0200] It should be noted that S1 to S14 in Tables 1 and 2 refer to Examples 1 to 14, respectively, and D1 to D5 refer to Comparative Examples 1 to 5, respectively.

[0201] The test data from Examples 1-14 (S1~S14) show that the coke obtained by the low-quality raw coke in this application through a low-temperature calcination process can satisfy the relationship 90≤T / [(S×R)^5+R^3]≤1000, which can achieve a balance between the tap density and the degree of defects of the coke. The structure of the coke is more compact and orderly, which can reduce the internal and surface defects of the coke, improve the graphitization degree of the graphite anode material obtained by coke graphitization treatment, and improve the specific capacity, tap density and rate performance of the graphite anode material.

[0202] The R value of the coke in Example 14 was too small, the degree of defect in the coke was low, and the lithium-ion transport channels were reduced, resulting in a decrease in the material capacity after coke graphitization and a slight decrease in the initial coulombic efficiency.

[0203] The data results from Example 1 (S1) and Comparative Example 1 (D1) show that Comparative Example 1 does not treat the coke raw material, and the coke does not satisfy the relationship T / [(S×R)^5+R^3]. The internal and surface defects of the coke increase significantly, the R value is too large, the orientation of the graphitized material is too high, the degree of graphitization is low, and the specific capacity and first efficiency are both very low.

[0204] The data from Example 1 (S1) and Comparative Example 2 (D2) show that without low-temperature calcination and secondary coking of the raw materials, the impregnating agent cannot be fully filled into the raw coke. The coke does not satisfy the relationship T / [(S×R)^5+R^3]. The coke has a low tap density, a large specific surface area, and an excessively large R value, meaning that the amorphous carbon content in the coke is increased, the coke has a low degree of order, contains many defect structures and vacancies, has a low degree of graphitization, and is too highly oriented. During charging and discharging, this will cause stress concentration between graphite layers, leading to structural damage phenomena such as peeling and cracking of graphite layers, reducing the structural stability of the negative electrode material, and decreasing the capacity retention rate of the battery.

[0205] The data from Example 1 (S1) and Comparative Example 3 (D3) show that without high-temperature calcination, the amorphous carbon content in the coke is high, making it difficult to effectively promote the free radical reaction (aromatic dehydrogenation condensation reaction) between the impregnating agent and the organic matter and incompletely coked components in the raw coke. The cross-linking reaction between the lamellar molecules is reduced, resulting in a decrease in the microscopic order of the coke structure. The coke does not satisfy the relationship T / [(S×R)^5+R^3], the tap density of the coke decreases, the R value is too large, and the mechanical strength of the carbon skeleton structure decreases. The specific capacity and degree of graphitization of the graphitized anode material are both low.

[0206] The results from Example 1 (S1) and Comparative Example 4 (D4) show that without low-temperature impregnation treatment, the defects and pore structures in the coke increase, the microscopic order of the coke structure decreases, the coke does not satisfy the relationship T / [(S×R)^5+R^3], the tap density of the coke decreases, the specific surface area increases, and the R value is too large, resulting in excessively high orientation of the graphitized negative electrode material, which reduces the structural stability of the negative electrode material and decreases the capacity retention rate of the battery.

[0207] The results from Example 1 (S1) and Comparative Example 5 (D5) show that without the addition of PTFE powder to the impregnating agent, the number of CF bonds in the carbon skeleton decreases, the mechanical strength of the carbon skeleton decreases, the structural order of the coke decreases, the coke does not satisfy the relationship T / [(S×R)^5+R^3], the tap density of the coke decreases, the specific surface area increases, and the R value is too large, resulting in excessively high orientation of the graphitized negative electrode material, which reduces the structural stability of the negative electrode material and decreases the capacity retention rate of the battery.

[0208] In summary, the coke provided in this application has a significantly reduced amorphous carbon content and an improved microstructural order; the internal structural defects are reduced, thus lowering the specific surface area of ​​the raw coke; the mechanical strength is enhanced after calcination; a large amount of light components such as aliphatic hydrocarbons and a small amount of aromatic hydrocarbons are removed, reducing the material's bonding index and increasing its true density; the vacancies and defects in the raw coke structure are effectively eliminated, which is beneficial for subsequent processing; and the graphitization degree and specific capacity of the graphite anode material made from the modified coke raw material are further improved.

[0209] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A type of coke, characterized in that the coke... The coke has pores and a specific surface area of ​​Sm. 2 / g, tap density is T g / cm³ 3 ; The focal length was tested using Raman surface scanning, and the resulting test image, after fitting, was within 1200±10 cm. -1 It has the first carbon characteristic peak and the peak area is I1, at 1350 cm⁻¹. -1 ~1380cm -1 It has a second carbon characteristic peak with a peak area of ​​I2 within the range, at 1460 cm⁻¹ -1 ~1530cm -1 It has a third carbon characteristic peak with a peak area of ​​I3 within the range, at 1580 cm⁻¹. -1 ±10cm -1 The fourth carbon characteristic peak is located at the point with a peak area of ​​I4, and R = I1 / (I1+I2+I3+I4); The coke satisfies: 90≤T / [(S×R)^5+R^3]≤1000.

2. The coke according to claim 1, characterized in that, T / [(S×R)^5+R^3] is a range consisting of 90, 100, 200, 300, 400, 550, 670, 880, 920, 980, 1000, or any two of them.

3. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1)0.5≤S≤2.6； (2)0.3≤T≤1.8； (3)0.1≤R≤0.22。 4. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The specific surface area of ​​the coke is 0.5 m². 2 / g, 0.7m 2 / g, 1.5m 2 / g, 1.6m 2 / g, 1.9m 2 / g, 2.0m 2 / g, 2.25m 2 / g, 2.5m 2 / g, 2.57m 2 / g, 2.6m 2 / g or a range consisting of any two of them; (2) The tap density of the coke is 0.3 g / cm³. 3 0.6g / cm 3 0.9g / cm 3 1.1g / cm 3 1.3g / cm 3 1.5g / cm 3 1.8g / cm 3 or a range consisting of any two of them; (3) R is a range consisting of 0.1, 0.12, 0.13, 0.15, 0.17, 0.19, 0.198, 0.2, 0.22 or any two of them.

5. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The ratio K1 between the half-width at half maximum (WHM) of the first carbon characteristic peak and the half-width at half maximum (WHM) of the fourth carbon characteristic peak is 1.84 to 2.99; (2) The ratio K2 between the half-width at half maximum (WHM) of the second carbon characteristic peak and the half-width at half maximum (WHM) of the fourth carbon characteristic peak is 1.16 to 1.

76. (3) The ratio K3 between the half width at half maximum (WHM) of the third carbon characteristic peak and the half width at half maximum (WHM) of the fourth carbon characteristic peak is 0.76 to 2.

63.

6. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The ratio K1 between the half width at half maximum (WHM) of the first carbon characteristic peak and the half width at half maximum (WHM) of the fourth carbon characteristic peak is a range of 1.84, 1.91, 1.95, 1.98, 2.01, 2.04, 2.08, 2.09, 2.99 or any two of them. (2) The ratio K2 between the half width at half maximum (WHM) of the second carbon characteristic peak and the half width at half maximum (WHM) of the fourth carbon characteristic peak is a range of 1.16, 1.46, 1.48, 1.56, 1.58, 1.61, 1.63, 1.65, 1.76 or any two of these ranges. (3) The ratio K3 between the half-width at half maximum (WHM) of the third carbon characteristic peak and the half-width at half maximum (WHM) of the fourth carbon characteristic peak is a range of 0.76, 1.35, 1.50, 1.67, 1.82, 2.01, 2.25, 2.55, 2.63 or any two of them.

7. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1)3.2≤(I1+I2+I3) / I4≤5.16; (2) (I1+I2+I3) / I4 is a range consisting of 3.2, 3.5, 3.7, 3.9, 4.0, 4.2, 4.6, 4.8, 4.9, 5.1, 5.16 or any two of them.

8. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1)0.28≤I3 / (I1+I2+I3+I4)≤0.45; (2) I3 / (I1+I2+I3+I4) is a range consisting of 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45 or any two of them.

9. The coke according to claim 1, characterized in that, The focal point satisfies at least one of the following characteristics: (1)0.23≤I2 / (I1+I2+I3+I4)≤0.34; (2) I2 / (I1+I2+I3+I4) is a range consisting of 0.23, 0.25, 0.26, 0.27, 0.28, 0.30, 0.31, 0.32, 0.33, 0.34 or any two of them.

10. The coke according to any one of claims 1 to 5, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The true density of the char is 1.6 g / cm³. 3 ~2.2g / cm 3 ; (2) The volatile matter content in the coke is 0.8% to 7% by mass; (3) The total mass content of magnetic materials in the coke is 50ppm to 300ppm; (4) The coke contains fluorine, and the mass content of fluorine in the coke is 10 mg / kg to 30 mg / kg; (5) The ash content in the coke is ≤0.5% by mass.

11. The coke according to any one of claims 1 to 5, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The true density of the char is 1.6 g / cm³. 3 1.8g / cm 3 1.9g / cm 3 2.0g / cm 3 2.1g / cm 3 2.15g / cm 3 2.2g / cm 3 or a range consisting of any two of them; (2) The volatile matter content in the coke is 0.8% to 7%, specifically it can be 0.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7% or any two of them.

12. The coke according to any one of claims 1 to 5, characterized in that, The focal point satisfies at least one of the following characteristics: (1) The mass content of F element in the char is a range of 10 mg / kg, 12.5 mg / kg, 15 mg / kg, 20 mg / kg, 22.7 mg / kg, 28 mg / kg, 30 mg / kg or any two of these; (2) The ash content in the coke is a range of 0.5%, 0.4%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1% or any two of these.

13. The coke according to any one of claims 1 to 9, characterized in that, The magnetic material in the coke includes the following components: Fe < 200 ppm, Co < 10 ppm, Cu < 10 ppm, Ni < 15 ppm, Al < 200 ppm, Cr < 20 ppm, Zn < 20 ppm, Mg < 50 ppm, Mn < 16 ppm, Na < 300 ppm, K < 30 ppm, Ca < 300 ppm, Si < 50 ppm, V < 100 ppm.

14. A negative electrode material, characterized in that, The negative electrode material includes graphite material prepared from coke as described in any one of claims 1 to 13.

15. A battery, characterized in that, The battery includes the negative electrode material as described in claim 14.

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