Carbon material and preparation method thereof

Abstract

The invention belongs to the technical field of carbon materials, and particularly relates to a carbon material and a preparation method thereof. In order to solve the problem that in the prior art, the mechanical strength of a graphitized carbon material is not high mostly, the invention provides a carbon material and a preparation method thereof, and the stone camber of the carbon material is 3-32 MPa; the stone camber is defined and calculated according to the following formula: stone camber = graphitization degree * average bending strength; the average bending strength is equal to (the upper surface bending strength + the side surface bending strength) / 2; a test method of the graphitization degree is an XRD (X-Ray Diffraction) method and is calculated by using a Franklin formula; and the test standard of the bending strength is JB / T 8133.7-2013. The performance index of the stone camber is defined, and the graphitization degree of the carbon material and the mechanical strength after graphitization can be comprehensively reflected, so that the carbon material can be applied to some extreme working conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of graphite fiber composite materials, and particularly relates to a graphite fiber composite with better pore resistance and a preparation method thereof. Background Art

[0002] With the rapid development of new energy, aerospace, nuclear energy and other high-tech fields, the demand for high-performance carbon materials is becoming increasingly urgent. Carbon materials are widely used in key fields such as electrodes, braking components, and thermal management materials due to their excellent high-temperature stability, electrical conductivity, corrosion resistance, and lightweight characteristics. The graphitization degree can improve the graphite characteristics of carbon materials, such as electrical conductivity and lubricity. However, once the carbon materials in the prior art have a high graphitization degree, it is difficult to ensure good mechanical strength at the same time, resulting in limited applications in specific scenarios and difficulty in meeting the application requirements under extreme working conditions.

[0003] For example, a Chinese patent application for invention discloses a preparation method of a porous graphitized carbon material [Application No.: 202110374300.6]. This patent application for invention includes the following steps: 1) Using low molecular weight polycarbosilane (LPCS) and iron carbonyl as raw materials, and decalin as a reaction solvent, preparing sol particles with PCS as the shell and multi-core carbon-based iron derivatives as the core (multi-core carbonyl iron @ PCS); 2) Mixing the sol particles obtained in step 1) with pitch in a decalin solution, and removing the solvent by vacuum distillation to obtain pitch-coated multi-core carbon-based iron derivatives; 3) Oxidatively crosslinking and pyrolyzing the pitch-coated multi-core carbon-based iron derivatives obtained in step 2) at high temperature to carbonize the pitch, and at the same time converting the multi-core carbon-based iron derivatives in the core through "organic-inorganic" transformation to generate inorganic metal compounds; 4) Etching the sample obtained in step 3) with hydrofluoric acid to remove the internal metal silicide, and preparing a hollow porous graphitized carbon material.

[0004] Although this patent application for invention has the advantage of being able to control the pore size and graphitization of the material, it still does not consider the mechanical strength after graphitization of the material and is difficult to meet the application requirements under extreme working conditions. Summary of the Invention

[0005] The purpose of the present invention is to provide a carbon material with excellent stone curvature for the above problems.

[0006] Another purpose of the present invention is to provide a preparation method for preparing a carbon material with excellent stone curvature for the above problems.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions: A carbon material, characterized in that: the stone bending degree of the carbon material is 3 to 32 MPa; It is defined that the stone bending degree is calculated by the following formula: Stone bending degree = graphitization degree * average flexural strength; Average flexural strength = (upper surface flexural strength + side flexural strength) / 2; The test method for the graphitization degree is the XRD diffraction method and is calculated using the Franklin formula; The test standard for the flexural strength is JB / T 8133.7 - 2013.

[0008] In the above - mentioned carbon material, the stone bending degree of the carbon material is 3 to 6 MPa.

[0009] In the above - mentioned carbon material, the stone bending degree of the carbon material is 6 to 9 MPa.

[0010] In the above - mentioned carbon material, the stone bending degree of the carbon material is 9 to 12 MPa.

[0011] In the above - mentioned carbon material, the stone bending degree of the carbon material is 12 to 15 MPa.

[0012] In the above - mentioned carbon material, the stone bending degree of the carbon material is 15 to 18 MPa.

[0013] In the above - mentioned carbon material, the stone bending degree of the carbon material is 18 to 21 MPa.

[0014] In the above - mentioned carbon material, the stone bending degree of the carbon material is 21 to 24 MPa.

[0015] In the above - mentioned carbon material, the stone bending degree of the carbon material is 24 to 27 MPa.

[0016] In the above - mentioned carbon material, the stone bending degree of the carbon material is 27 to 30 MPa.

[0017] In the above - mentioned carbon material, the stone bending degree of the carbon material is 30 to 32 MPa.

[0018] A preparation method for preparing the above - mentioned carbon material, comprising the following steps: Step 1: Ball-mill and crush 60 - 80 parts by mass of petroleum coke under argon protection to obtain nano-scale petroleum coke particles. Add 12 - 18 parts by mass of short carbon fiber, 2 - 4 parts by mass of graphene, 5 - 7 parts by mass of phenolic resin, and 0.5 - 2 parts by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed additive; the short carbon fiber can serve as a reinforcing framework to improve the overall flexural strength of the material; the phenolic resin can serve as a temporary binder during the subsequent cold isostatic pressing process, endowing the material with sufficient mechanical strength to prevent cracking. At the same time, during the carbonization stage, the phenolic resin can pyrolyze to form amorphous carbon to fill the pores of the material, thereby improving the material density and the final flexural strength.

[0019] Step 2: Dissolve 4 - 6 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, and then add the nano-scale petroleum coke particles prepared in Step 1. After mixing evenly, add the mixed additive prepared in Step 1, and spray-dry to obtain a uniform composite powder; Ni(NO3)2·6H2O can introduce nickel nanoparticles as a graphitization template in a high-temperature environment, acting as a catalyst to reduce the required graphitization temperature, thereby reducing the damage to the structure caused by high temperature; Step 3: Perform cold isostatic pressing on the uniform composite powder prepared in Step 2, with a pressure of 250 - 350 MPa and a pressure-holding time of 20 - 40 min. Through cold isostatic pressing, the material can eliminate anisotropy and improve the lateral flexural strength; Step 4: Then heat at a heating rate of 5 °C / min to 550 - 650 °C, and then naturally cool to room temperature; Step 5: Then, under argon protection, heat at a heating rate of 10 °C / min to 800 - 1200 °C and hold for 1.5 - 2.5 h; Step 6: Then heat at a heating rate of 15 °C / min to 1600 - 2000 °C and hold for 3 - 5 h to obtain a crude graphite product; Step 7: Cool to 1000 - 1200 °C and introduce a reaction gas containing methane, and pyrolyze for 1.5 - 2.5 h to deposit pyrolytic carbon on the surface of the crude graphite product, and then naturally cool to room temperature to obtain a finished carbon material.

[0020] Methane pyrolysis can deposit pyrolytic carbon on the material surface to fill the pores of the material, improving the density and interface bonding.

[0021] In the above preparation method of the carbon material, the D50 of the nano-scale petroleum coke particles in Step 1 is 200 nm.

[0022] In the above preparation method of the carbon material, the length of the short carbon fiber in Step 1 is 3 mm and the diameter is 7 μm.

[0023] In the above method for preparing the carbon material, in Step 7, the reaction gas is a mixed gas of methane and hydrogen, the volume ratio of methane to hydrogen is 1:4, and the flow rate of the reaction gas is 500 sccm.

[0024] Pure methane cracking may have the possibility of too fast cracking speed, resulting in uneven carbon deposition, making it difficult to control the formation of amorphous carbon or structures such as carbon nanotubes and graphene. In addition, too fast deposition may lead to stress concentration inside the material, generating cracks and affecting the mechanical properties of the material.

[0025] Compared with the existing technologies, the advantages of the present invention are as follows: 1. The present invention defines a performance index of stone curvature, which can comprehensively reflect the graphitization degree of the carbon material and the mechanical strength after graphitization, enabling the carbon material to be applied to some extreme working conditions.

[0026] 2. The present invention includes a cold isostatic pressing forming step. Through cold isostatic pressing forming, the anisotropy of the material can be eliminated, and the side bending strength can be improved.

[0027] 3. After graphitization, the present invention also deposits cracked carbon on the surface of the material through a methane cracking step to fill the pores of the material, improve the density and interface bonding. At the same time, part of hydrogen is mixed in the gas used for cracking, thus avoiding the problem of uneven carbon deposition and the formation of amorphous carbon caused by too fast cracking speed. Specific Embodiments

[0028] The following further elaborates on the present invention in detail in combination with specific embodiments.

[0029] Example 1 This example provides a carbon material and its preparation method, including the following steps: Step 1: Ball-mill and crush 70 parts by mass of petroleum coke under argon protection to obtain nano-scale petroleum coke particles with a D50 of 200 nm. Add 15 parts by mass of short-cut carbon fibers, 3 parts by mass of graphene, 6 parts by mass of phenolic resin, and 1 part by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed auxiliary agent. Among them, the length of the short-cut carbon fibers is 3 mm and the diameter is 7 μm; Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, then add the nano-scale petroleum coke particles prepared in Step 1, mix evenly, and then add the mixed auxiliary agent prepared in Step 1, and spray-dry to obtain a uniform composite powder; Step 3: Perform cold isostatic pressing on the uniform composite powder prepared in Step 2, with a pressure of 300 MPa and a pressure holding time of 30 min; Step 4: Then heat it to 600 °C at a heating rate of 5 °C / min, and then naturally cool it to room temperature; Step Five: Under argon protection, heat it up to 1000 °C at a heating rate of 10 °C / min and hold for 2 h; Step Six: Then heat it up to 1800 °C at a heating rate of 15 °C / min and hold for 4 h to obtain the crude graphitized product; Step Seven: Cool it down to 1100 °C and introduce a reaction gas containing methane. The reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4. The flow rate of the reaction gas is 500 sccm, and pyrolyze for 2 h to deposit pyrolytic carbon on the surface of the crude graphitized product, and then naturally cool to room temperature to obtain the finished carbon material.

[0030] The graphitization degree of the finished carbon material measured by XRD diffraction method is 68%. Measure the flexural strength of the upper surface and the side surface of the finished carbon material by the method recorded in JB / T 8133.7 - 2013, and calculate the average flexural strength to be 44.9 MPa. Thus, the stone bending degree is calculated to be 30.53 MPa.

[0031] Example 2 This example provides a carbon material and its preparation method, including the following steps: Step One: Ball-mill and crush 60 parts by mass of petroleum coke under argon protection to obtain nanoscale petroleum coke particles with a D50 of 200 nm. Add 18 parts by mass of short carbon fibers, 4 parts by mass of graphene, 7 parts by mass of phenolic resin, and 2 parts by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed additive. Among them, the length of the short carbon fibers is 3 mm and the diameter is 7 μm; Step Two: Dissolve 6 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, then add the nanoscale petroleum coke particles prepared in Step One, mix evenly, and then add the mixed additive prepared in Step One, and spray-dry to obtain a uniform composite powder; Step Three: Cold isostatically press the uniform composite powder prepared in Step Two, with a pressure of 350 MPa and a pressure holding time of 40 min; Step Four: Then heat it up to 650 °C at a heating rate of 5 °C / min, and then naturally cool to room temperature; Step Five: Under argon protection, heat it up to 1200 °C at a heating rate of 10 °C / min and hold for 2.5 h; Step Six: Then heat it up to 2000 °C at a heating rate of 15 °C / min and hold for 5 h to obtain the crude graphitized product; Step 7: Cool down to 1200 °C and introduce a reaction gas containing methane. The reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4. The flow rate of the reaction gas is 500 sccm. Pyrolyze for 2.5 h to deposit pyrolytic carbon on the surface of the rough graphitized product, and then naturally cool to room temperature to obtain the finished carbon material.

[0032] The graphitization degree of the finished carbon material measured by XRD diffraction method is 70%. Measure the flexural strength of the upper surface and the side surface of the finished carbon material by the method recorded in JB / T 8133.7-2013, and calculate the average flexural strength to be 42.7 MPa. Thus, the stone bending degree is calculated to be 29.89 MPa.

[0033] Example 3 This example provides a carbon material and its preparation method, including the following steps: Step 1: Ball-mill and crush 80 parts by mass of petroleum coke under argon protection to obtain nano-sized petroleum coke particles with a D50 of 200 nm. Add 12 parts by mass of short-cut carbon fibers, 2 parts by mass of graphene, 5 parts by mass of phenolic resin, and 0.5 parts by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed auxiliary agent. Among them, the length of the short-cut carbon fibers is 3 mm and the diameter is 7 μm. Step 2: Dissolve 4 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, then add the nano-sized petroleum coke particles prepared in Step 1. After mixing evenly, add the mixed auxiliary agent prepared in Step 1, and spray-dry to obtain a uniform composite powder. Step 3: Cold isostatically press the uniform composite powder prepared in Step 2, with a pressure of 250 MPa and a pressure holding time of 20 min. Step 4: Then heat up to 550 - 650 °C at a heating rate of 5 °C / min, and then naturally cool to room temperature. Step 5: Then, under argon protection, heat up to 800 °C at a heating rate of 10 °C / min and hold for 1.5 h. Step 6: Then heat up to 1600 °C at a heating rate of 15 °C / min and hold for 3 h to obtain a rough graphitized product. Step 7: Cool down to 1000 °C and introduce a reaction gas containing methane. The reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4. The flow rate of the reaction gas is 500 sccm. Pyrolyze for 1.5 h to deposit pyrolytic carbon on the surface of the rough graphitized product, and then naturally cool to room temperature to obtain the finished carbon material.

[0034] The graphitization degree of the finished carbon material measured by XRD diffraction method is 64%. The upper surface flexural strength and side flexural strength of the finished carbon material are measured by the method described in JB / T 8133.7-2013, and the average flexural strength is calculated to be 45.5 MPa. Thus, the stone flexure is calculated to be 29.12 MPa.

[0035] Comparative Example 1 This comparative example provides a carbon material and its preparation method, including the following steps: Step 1: 70 parts by mass of petroleum coke is ball-milled and pulverized under argon protection to obtain nanoscale petroleum coke particles with a D50 of 200 nm. 15 parts by mass of short carbon fibers, 3 parts by mass of graphene, 6 parts by mass of phenolic resin, and 1 part by mass of PVP are added to ethanol and ball-milled to obtain a mixed additive. Among them, the short carbon fibers have a length of 3 mm and a diameter of 7 μm; Step 2: 5 parts by mass of Ni(NO3)2·6H2O is dissolved in ethanol, ultrasonically dispersed, and then added to the nanoscale petroleum coke particles prepared in Step 1. After mixing evenly, the mixed additive prepared in Step 1 is added, and spray drying is performed to obtain a uniform composite powder; Step 3: Then, it is heated to 600 °C at a heating rate of 5 °C / min and then naturally cooled to room temperature; Step 4: Then, under argon protection, it is heated to 1000 °C at a heating rate of 10 °C / min and held for 2 h; Step 5: Then, it is heated to 1800 °C at a heating rate of 15 °C / min and held for 4 h to obtain a crude graphitized product; Step 6: It is cooled to 1100 °C, and a reaction gas containing methane is introduced. The reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4. The flow rate of the reaction gas is 500 sccm, and cracking is performed for 2 h to deposit cracked carbon on the surface of the crude graphitized product, and it is naturally cooled to room temperature to obtain the finished carbon material.

[0036] The graphitization degree of the finished carbon material measured by XRD diffraction method is 68%. The upper surface flexural strength and side flexural strength of the finished carbon material are measured by the method described in JB / T 8133.7-2013, and the average flexural strength is calculated to be 41.2 MPa. Thus, the stone flexure is calculated to be 28.02 MPa.

[0037] Comparative Example 2 This comparative example provides a carbon material and its preparation method, including the following steps: Step 1: Grind 70 parts by mass of petroleum coke under argon protection to obtain nanoscale petroleum coke particles with a D50 of 200 nm for the nanoscale petroleum coke particles. Add 15 parts by mass of short carbon fiber, 3 parts by mass of graphene, 6 parts by mass of phenolic resin, and 1 part by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed additive. Among them, the short carbon fiber has a length of 3 mm and a diameter of 7 μm; Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, add the nanoscale petroleum coke particles prepared in Step 1, mix evenly, and then add the mixed additive prepared in Step 1, and spray-dry to obtain a uniform composite powder; Step 3: Cold isostatically press the uniform composite powder prepared in Step 2, with a pressure of 300 MPa and a pressure holding time of 30 min; Step 4: Then heat it up to 600 °C at a heating rate of 5 °C / min, and then naturally cool it to room temperature; Step 5: Then, under argon protection, heat it up to 1000 °C at a heating rate of 10 °C / min and hold the temperature for 2 h; Step 6: Then heat it up to 1800 °C at a heating rate of 15 °C / min and hold the temperature for 4 h to obtain a finished carbon material.

[0038] The graphitization degree of the finished carbon material measured by XRD diffraction method is 68%. Measure the flexural strength of the upper surface and the flexural strength of the side surface of the finished carbon material by the method recorded in JB / T 8133.7 - 2013, and calculate the average flexural strength to be 28.6 MPa. Thus, the stone flexure degree is calculated to be 19.45 MPa.

[0039] Comparative Example 3 This comparative example provides a carbon material and its preparation method, including the following steps: Step 1: Grind 70 parts by mass of petroleum coke under argon protection to obtain nanoscale petroleum coke particles with a D50 of 200 nm for the nanoscale petroleum coke particles. Add 15 parts by mass of short carbon fiber, 3 parts by mass of graphene, 6 parts by mass of phenolic resin, and 1 part by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed additive. Among them, the short carbon fiber has a length of 3 mm and a diameter of 7 μm; Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, add the nanoscale petroleum coke particles prepared in Step 1, mix evenly, and then add the mixed additive prepared in Step 1, and spray-dry to obtain a uniform composite powder; Step 3: Cold isostatically press the uniform composite powder prepared in Step 2, with a pressure of 300 MPa and a pressure holding time of 30 min; Step 4: Then, heat it up to 600 °C at a heating rate of 5 °C / min, and then cool it naturally to room temperature; Step 5: Then, under the protection of argon, heat it up to 1000 °C at a heating rate of 10 °C / min, and keep the temperature for 2 h; Step 6: Then, heat it up to 1800 °C at a heating rate of 15 °C / min, and keep the temperature for 4 h to obtain the crude graphite product; Step 7: Cool it down to 1100 °C, and introduce methane gas with a flow rate of 500 sccm, and pyrolyze for 2 h to deposit the pyrolytic carbon on the surface of the crude graphite product, and then cool it naturally to room temperature to obtain the finished carbon material.

[0040] The graphitization degree of the finished carbon material measured by the XRD diffraction method is 68%. The upper surface bending strength and the side surface bending strength of the finished carbon material are measured by the method described in JB / T 8133.7-2013, and the average bending strength is calculated to be 31.7 MPa. Thus, the stone bending degree is calculated to be 21.56 MPa.

[0041] Comparative Example 4 This comparative example provides a carbon material and its preparation method, including the following steps: Step 1: Ball-mill and crush 70 parts by mass of petroleum coke under the protection of argon to obtain nano-scale petroleum coke particles with a D50 of 200 nm. Add 15 parts by mass of short-cut carbon fibers, 3 parts by mass of graphene, 6 parts by mass of phenolic resin, and 1 part by mass of PVP to ethanol, and ball-mill and mix them to obtain a mixed additive. The length of the short-cut carbon fibers is 3 mm, and the diameter is 7 μm; Step 2: Disperse 5 parts by mass of nickel powder in ethanol, add it to the nano-scale petroleum coke particles prepared in Step 1 after ultrasonic dispersion, mix them evenly, and then add the mixed additive prepared in Step 1, and spray-dry to obtain a uniform composite powder; Step 3: Cold isostatically press the uniform composite powder prepared in Step 2, with a pressure of 300 MPa and a pressure holding time of 30 min; Step 4: Then, heat it up to 600 °C at a heating rate of 5 °C / min, and then cool it naturally to room temperature; Step 5: Then, under the protection of argon, heat it up to 1000 °C at a heating rate of 10 °C / min, and keep the temperature for 2 h; Step 6: Then, heat it up to 1800 °C at a heating rate of 15 °C / min, and keep the temperature for 4 h to obtain the crude graphite product; Step 7: Cool down to 1100 °C and introduce a reaction gas containing methane. The reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4. The flow rate of the reaction gas is 500 sccm. Carry out pyrolysis for 2 h to deposit pyrolytic carbon on the surface of the rough graphitized product, and then naturally cool to room temperature to obtain the finished carbon material.

[0042] The graphitization degree of the finished carbon material measured by XRD diffraction method is 51%. Measure the flexural strength of the upper surface and the side surface of the finished carbon material by the method described in JB / T 8133.7-2013, and calculate the average flexural strength to be 48.4 MPa. Thus, the stone flexure degree is calculated to be 24.68 MPa.

[0043] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A carbon material, characterized in that: The stone bending strength of the carbon material is 3 - 32 MPa; It is defined that the stone bending strength is calculated by the following formula: Stone bending strength = graphitization degree * average flexural strength; Average flexural strength = (upper surface flexural strength + side surface flexural strength) / 2; The test method for the graphitization degree is the XRD diffraction method and is calculated using the Franklin formula; The test standard for the flexural strength is JB / T 8133.7 - 2013.

2. The carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 3 - 6 MPa.

3. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 6 - 9 MPa.

4. A carbon material according to claim 1, wherein: The stone bending strength of the carbon material is 9 - 12 MPa.

5. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 12 - 15 MPa.

6. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 15 - 18 MPa.

7. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 18 - 21 MPa.

8. A carbon material as described in claim 1, characterized in that: The stone bending strength of the carbon material is 21 - 24 MPa.

9. A carbon material according to claim 1, wherein: The stone bending strength of the carbon material is 24 - 27 MPa.

10. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 27 - 30 MPa.

11. A carbon material according to claim 1, characterized in that: The stone bending strength of the carbon material is 30 - 32 MPa.

12. A method for preparing the carbon material according to any one of claims 1-11, characterized in that, It includes the following steps: Step 1: Ball-mill and crush 60 - 80 parts by mass of petroleum coke under argon protection to obtain nano-scale petroleum coke particles. Add 12 - 18 parts by mass of short carbon fibers, 2 - 4 parts by mass of graphene, 5 - 7 parts by mass of phenolic resin, and 0.5 - 2 parts by mass of PVP to ethanol, and ball-mill and mix to obtain a mixed additive; Step 2: Dissolve 4 - 6 parts by mass of Ni(NO3)2·6H2O in ethanol, ultrasonically disperse it, then add the nano-scale petroleum coke particles prepared in Step 1. After mixing evenly, add the mixed additive prepared in Step 1, and spray-dry to obtain a uniform composite powder; Step 3: Cold isostatically press the uniform composite powder prepared in Step 2, with a pressure of 250 - 350 MPa and a pressure holding time of 20 - 40 min; Step 4: Then heat it at a heating rate of 5 °C / min to 550 - 650 °C, and then naturally cool it to room temperature; Step 5: Then, under argon protection, heat it at a heating rate of 10 °C / min to 800 - 1200 °C, and keep it warm for 1.5 - 2.5 h; Step 6: Then heat it at a heating rate of 15 °C / min to 1600 - 2000 °C, and keep it warm for 3 - 5 h to obtain a rough graphitized product; Step 7: Cool it down to 1000 - 1200 °C, and introduce a reaction gas containing methane, and pyrolyze for 1.5 - 2.5 h, so that the pyrolytic carbon deposits on the surface of the rough graphitized product, and then naturally cool it to room temperature to obtain the finished carbon material.

13. The preparation method of the carbon material according to claim 12, characterized in that: The D50 of the nano-scale petroleum coke particles in Step 1 is 200 nm.

14. The preparation method of the carbon material according to claim 12, characterized in that: The length of the short carbon fibers in Step 1 is 3 mm, and the diameter is 7 μm.

15. The preparation method of the carbon material according to claim 12, characterized in that: In Step 7, the reaction gas is a mixed gas of methane and hydrogen, and the volume ratio of methane to hydrogen is 1:4, and the flow rate of the reaction gas is 500 sccm.