A carbon material and a preparation method thereof

Abstract

The present application belongs to the technical field of carbon materials, and particularly relates to a carbon material and a preparation method thereof. In view of the problem that the mechanical strength of carbon materials after graphitization is generally not high in the prior art, the present application provides a carbon material and a preparation method thereof, wherein the graphitization degree of the carbon material is 3-32 MPa; the graphitization degree is calculated by the following formula: graphitization degree = graphitization degree * average bending strength; average bending strength = (upper surface bending strength + side surface bending strength) / 2; the test method of the graphitization degree is XRD diffraction method, and the calculation is performed by using the Franklin formula; and the test standard of the bending strength is JB / T 8133.7-2013. The present application defines the performance index of the graphitization degree, which can comprehensively reflect the graphitization degree of the carbon material and the mechanical strength after graphitization, 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 in particular relates to a graphite fiber composite material with better pore resistance and a preparation method thereof. Background Art

[0002] With the rapid development of high-tech fields such as new energy, aerospace, and nuclear energy, the demand for high-performance carbon materials is becoming increasingly urgent. Due to their excellent high-temperature stability, electrical conductivity, corrosion resistance, and lightweight properties, carbon materials are widely used in key areas such as electrodes, brake components, and thermal management materials. The degree of graphitization can improve the graphite properties of carbon materials, such as electrical conductivity and lubricity. However, once the degree of graphitization is high, existing carbon materials cannot guarantee sufficient mechanical strength. This limits their use in specific application scenarios and makes them difficult to meet the requirements of applications under extreme working conditions.

[0003] For example, a Chinese invention patent application discloses a method for preparing a porous graphitized carbon material [application number: 202110374300.6], which includes the following steps:

[0004] 1) Using low molecular weight polycarbosilane (LPCS) and carbonyl iron as raw materials and decalin as the reaction solvent, sol particles with PCS as the shell and a polynuclear carbonyl iron derivative as the core (polynuclear carbonyl iron@PCS) were prepared;

[0005] 2) mixing the sol particles obtained in step 1) with asphalt in a decahydronaphthalene solution, and removing the solvent by vacuum distillation to obtain a asphalt-coated polynuclear carbon-based iron derivative;

[0006] 3) oxidatively crosslinking and pyrolyzing the asphalt-coated multi-nuclear carbon-based iron derivative obtained in step 2) at high temperature to carbonize the asphalt, and simultaneously converting the multi-nuclear carbon-based iron derivative in the inner core into an inorganic metal compound through an "organic-inorganic" transformation;

[0007] 4) etching the sample obtained in step 3) with hydrofluoric acid to remove the internal metal silicide to obtain a hollow porous graphitized carbon material.

[0008] Although this invention patent application has the advantage of being able to control the pore size and graphitization of the material, it still does not take into account the mechanical strength of the material after graphitization, and it is difficult to meet the application requirements under extreme working conditions. Summary of the Invention

[0009] The object of the present invention is to provide a carbon material with excellent curvature in order to solve the above problems.

[0010] Another object of the present invention is to provide a method for preparing a carbon material with excellent curvature in order to solve the above-mentioned problem.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A carbon material, characterized in that: the curvature of the carbon material is 3 to 32 MPa;

[0013] The curvature of the stone is calculated by the following formula:

[0014] Stone curvature = graphitization degree * average flexural strength;

[0015] Average bending strength = (upper surface bending strength + side bending strength) / 2;

[0016] The test method of the graphitization degree is XRD diffraction method, which is calculated using Franklin formula;

[0017] The testing standard for the flexural strength is JB / T 8133.7-2013.

[0018] In the above-mentioned carbon material, the curvature of the carbon material is 3 to 6 MPa.

[0019] In the above-mentioned carbon material, the curvature of the carbon material is 6 to 9 MPa.

[0020] In the above-mentioned carbon material, the curvature of the carbon material is 9 to 12 MPa.

[0021] In the above-mentioned carbon material, the curvature of the carbon material is 12 to 15 MPa.

[0022] In the above-mentioned carbon material, the curvature of the carbon material is 15 to 18 MPa.

[0023] In the above-mentioned carbon material, the curvature of the carbon material is 18 to 21 MPa.

[0024] In the above-mentioned carbon material, the curvature of the carbon material is 21 to 24 MPa.

[0025] In the above-mentioned carbon material, the curvature of the carbon material is 24-27 MPa.

[0026] In the above-mentioned carbon material, the curvature of the carbon material is 27 to 30 MPa.

[0027] In the above-mentioned carbon material, the curvature of the carbon material is 30 to 32 MPa.

[0028] A method for preparing the above-mentioned carbon material comprises the following steps:

[0029] Step one: under the protection of argon, 60-80 parts by mass of petroleum coke is ball milled to obtain nanoscale petroleum coke particles; 12-18 parts by mass of chopped 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 are added into ethanol and ball milled to obtain a mixed additive; the chopped carbon fiber can be used as a reinforcing framework to improve the overall bending strength of the material; the phenolic resin can be used as a temporary binder in the subsequent cold isostatic pressing process to give the material sufficient mechanical strength and prevent cracking; meanwhile, the phenolic resin can pyrolyze to generate amorphous carbon to fill the pores of the material, thereby improving the density and the final bending strength of the material.

[0030] Step two: 4-6 parts by mass of Ni(NO3)2·6H2O is dissolved in ethanol and ultrasonically dispersed, and then the nanoscale petroleum coke particles prepared in step one are added and mixed uniformly; the mixed additive prepared in step one is then added, and spray drying is performed to obtain a uniform composite powder; the Ni(NO3)2·6H2O can introduce nickel nanoparticles as a graphitization template under a high-temperature environment, thereby acting as a catalyst to reduce the required graphitization temperature and thus reduce the damage to the structure caused by high temperature.

[0031] Step three: the uniform composite powder prepared in step two is cold isostatic pressed at a pressure of 250-350 MPa for 20-40 min; the cold isostatic pressing can eliminate the anisotropy of the material and improve the side bending strength.

[0032] Step four: the temperature is raised to 550-650℃ at a rate of 5℃ / min, and then naturally cooled to room temperature.

[0033] Step five: under the protection of argon, the temperature is raised to 800-1200℃ at a rate of 10℃ / min, and held for 1.5-2.5 h.

[0034] Step six: the temperature is raised to 1600-2000℃ at a rate of 15℃ / min, and held for 3-5 h to obtain a graphitized crude product.

[0035] Step seven: the temperature is lowered to 1000-1200℃, and a reaction gas containing methane is introduced for 1.5-2.5 h to deposit pyrolysis carbon on the surface of the graphitized crude product, and then naturally cooled to room temperature to obtain a carbon material product.

[0036] The methane pyrolysis can deposit pyrolysis carbon on the surface of the material to fill the pores of the material and improve the density and the interface bonding.

[0037] In the above method for preparing the carbon material, the D50 of the nanoscale petroleum coke particles in step one is 200 nm.

[0038] In the above-mentioned method for preparing carbon materials, the length of the chopped carbon fibers in step 1 is 3 mm and the diameter is 7 μm.

[0039] In the above-mentioned method for preparing carbon materials, the reaction gas in step seven 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.

[0040] Pure methane cracking can result in excessively rapid cracking, leading to uneven carbon deposition and the formation of amorphous carbon or uncontrollable structures such as carbon nanotubes and graphene. Furthermore, excessively rapid deposition can lead to stress concentration within the material, causing cracks and compromising its mechanical properties.

[0041] Compared with the existing technology, the advantages of the present invention are:

[0042] 1. The present invention defines the performance index of stone curvature, which can comprehensively reflect the degree of graphitization of carbon materials and the mechanical strength after graphitization, so that carbon materials can be applied to certain extreme working conditions.

[0043] 2. The present invention includes a cold isostatic pressing step, which can eliminate the anisotropy of the material and improve the side bending strength.

[0044] 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, the gas used for cracking is also mixed with some hydrogen, thereby avoiding the problem of uneven carbon deposition caused by excessive cracking speed and the formation of amorphous carbon. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to specific embodiments.

[0046] Example 1

[0047] This embodiment provides a carbon material and a preparation method thereof, comprising the following steps:

[0048] Step 1: 70 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 15 parts by mass of chopped carbon fibers, 3 parts of graphene, 6 parts of phenolic resin, and 1 part of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0049] Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0050] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 300 MPa and a holding time of 30 min;

[0051] Step 4: Heat the sample to 600°C at a rate of 5°C / min, and then cool the sample to room temperature.

[0052] Step 5: Under argon protection, heat the mixture to 1000°C at a rate of 10°C / min and keep the temperature for 2 hours.

[0053] Step 6: heating the mixture to 1800°C at a rate of 15°C / min and keeping the temperature for 4 hours to obtain a crude graphitized product;

[0054] Step 7: Cool to 1100°C and introduce reaction gas containing methane. The reaction gas is a mixture 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. Pyrolysis is carried out for 2 hours to allow the cracked carbon to be deposited on the surface of the graphitized crude product. Naturally cool to room temperature to obtain a finished carbon material.

[0055] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 68%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 44.9 MPa. The calculated curvature was 30.53 MPa.

[0056] Example 2

[0057] This embodiment provides a carbon material and a preparation method thereof, comprising the following steps:

[0058] Step 1: 60 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 18 parts by mass of chopped carbon fibers, 4 parts of graphene, 7 parts of phenolic resin, and 2 parts of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0059] Step 2: Dissolve 6 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0060] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 350 MPa and a holding time of 40 min;

[0061] Step 4: Heat up to 650°C at a rate of 5°C / min, and then cool naturally to room temperature;

[0062] Step 5: Under argon protection, heat the mixture to 1200°C at a rate of 10°C / min and keep the temperature for 2.5 hours.

[0063] Step 6: heating the mixture to 2000°C at a rate of 15°C / min and maintaining the temperature for 5 hours to obtain a crude graphitized product;

[0064] Step 7: Cool to 1200°C and introduce reaction gas containing methane. The reaction gas is a mixture 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. The cracking is carried out for 2.5 hours, so that the cracked carbon is deposited on the surface of the graphitized crude product. Naturally cool to room temperature to obtain a finished carbon material.

[0065] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 70%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 42.7 MPa. The calculated graphitization was 29.89 MPa.

[0066] Example 3

[0067] This embodiment provides a carbon material and a preparation method thereof, comprising the following steps:

[0068] Step 1: 80 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 12 parts by mass of chopped carbon fiber, 2 parts of graphene, 5 parts of phenolic resin and 0.5 parts of PVP are added to ethanol, and the mixture is ball-milled to obtain a mixed additive, wherein the chopped carbon fiber has a length of 3 mm and a diameter of 7 μm;

[0069] Step 2: Dissolve 4 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0070] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 250 MPa and a holding time of 20 min;

[0071] Step 4: Heat the temperature to 550-650℃ at a rate of 5℃ / min, and then cool naturally to room temperature;

[0072] Step 5: Under argon protection, heat the mixture to 800°C at a rate of 10°C / min and keep the temperature for 1.5 hours.

[0073] Step 6: heating the mixture to 1600°C at a rate of 15°C / min and maintaining the temperature for 3 hours to obtain a crude graphitized product;

[0074] Step 7: Cool to 1000°C and introduce reaction gas containing methane, where the reaction gas is a mixture 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 the cracking is carried out for 1.5 hours, so that the cracked carbon is deposited on the surface of the graphitized crude product, and naturally cool to room temperature to obtain a finished carbon material.

[0075] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 64%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 45.5 MPa. The calculated curvature was 29.12 MPa.

[0076] Comparative Example 1

[0077] This comparative example provides a carbon material and a preparation method thereof, comprising the following steps:

[0078] Step 1: 70 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 15 parts by mass of chopped carbon fibers, 3 parts of graphene, 6 parts of phenolic resin, and 1 part of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0079] Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0080] Step 3: Heat up to 600°C at a rate of 5°C / min, and then cool naturally to room temperature;

[0081] Step 4: Under argon protection, heat the mixture to 1000°C at a rate of 10°C / min and keep the temperature for 2 hours.

[0082] Step 5: heating the mixture to 1800°C at a rate of 15°C / min and keeping the temperature for 4 hours to obtain a crude graphitized product;

[0083] Step 6: Cool down to 1100°C and introduce reaction gas containing methane. The reaction gas is a mixture 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. Pyrolysis is carried out for 2 hours to allow the cracked carbon to be deposited on the surface of the graphitized crude product. Naturally cool to room temperature to obtain a finished carbon material.

[0084] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 68%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 41.2 MPa. The calculated curvature was 28.02 MPa.

[0085] Comparative Example 2

[0086] This comparative example provides a carbon material and a preparation method thereof, comprising the following steps:

[0087] Step 1: 70 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 15 parts by mass of chopped carbon fibers, 3 parts of graphene, 6 parts of phenolic resin, and 1 part of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0088] Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0089] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 300 MPa and a holding time of 30 min;

[0090] Step 4: Heat the sample to 600°C at a rate of 5°C / min, and then cool the sample to room temperature.

[0091] Step 5: Under argon protection, heat the mixture to 1000°C at a rate of 10°C / min and keep the temperature for 2 hours.

[0092] Step 6: Heat the temperature to 1800°C at a rate of 15°C / min and keep the temperature for 4 hours to obtain the finished carbon material.

[0093] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 68%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 28.6 MPa. The calculated curvature was 19.45 MPa.

[0094] Comparative Example 3

[0095] This comparative example provides a carbon material and a preparation method thereof, comprising the following steps:

[0096] Step 1: 70 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 15 parts by mass of chopped carbon fibers, 3 parts of graphene, 6 parts of phenolic resin, and 1 part of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0097] Step 2: Dissolve 5 parts by mass of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0098] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 300 MPa and a holding time of 30 min;

[0099] Step 4: Heat the sample to 600°C at a rate of 5°C / min, and then cool the sample to room temperature.

[0100] Step 5: Under argon protection, heat the mixture to 1000°C at a rate of 10°C / min and keep the temperature for 2 hours.

[0101] Step 6: heating the mixture to 1800°C at a rate of 15°C / min and keeping the temperature for 4 hours to obtain a crude graphitized product;

[0102] Step 7: Cool to 1100°C and introduce methane gas at a flow rate of 500 sccm. Pyrolysis is performed for 2 hours to deposit the pyrolyzed carbon on the surface of the crude graphitized product. The product is then naturally cooled to room temperature to obtain a finished carbon material.

[0103] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 68%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 31.7 MPa. The calculated curvature was 21.56 MPa.

[0104] Comparative Example 4

[0105] This comparative example provides a carbon material and a preparation method thereof, comprising the following steps:

[0106] Step 1: 70 parts by mass of petroleum coke are ball-milled under argon protection to obtain nano-scale petroleum coke particles, wherein the D50 of the nano-scale petroleum coke particles is 200 nm, and 15 parts by mass of chopped carbon fibers, 3 parts of graphene, 6 parts of phenolic resin, and 1 part of PVP are added to ethanol and ball-milled to obtain a mixed additive, wherein the chopped carbon fibers have a length of 3 mm and a diameter of 7 μm;

[0107] Step 2: Disperse 5 parts by weight of nickel powder in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder;

[0108] Step 3: The uniform composite powder obtained in step 2 is subjected to cold isostatic pressing at a pressure of 300 MPa and a holding time of 30 min;

[0109] Step 4: Heat the sample to 600°C at a rate of 5°C / min, and then cool the sample to room temperature.

[0110] Step 5: Under argon protection, heat the mixture to 1000°C at a rate of 10°C / min and keep the temperature for 2 hours.

[0111] Step 6: heating the mixture to 1800°C at a rate of 15°C / min and keeping the temperature for 4 hours to obtain a crude graphitized product;

[0112] Step 7: Cool to 1100°C and introduce reaction gas containing methane. The reaction gas is a mixture 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. Pyrolysis is carried out for 2 hours to allow the cracked carbon to be deposited on the surface of the graphitized crude product. Naturally cool to room temperature to obtain a finished carbon material.

[0113] The graphitization degree of the finished carbon material was measured by XRD diffraction to be 51%. The top surface and side flexural strengths of the finished carbon material were measured using the method described in JB / T 8133.7-2013, and the average flexural strength was calculated to be 48.4 MPa. The calculated curvature was 24.68 MPa.

[0114] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for preparing a carbon material, characterized in that: The following steps are involved: Step 1: 60-80 parts by weight of petroleum coke are ball-milled under argon protection to obtain nano-sized petroleum coke particles, and 12-18 parts by weight of chopped carbon fibers, 2-4 parts of graphene, 5-7 parts of phenolic resin, and 0.5-2 parts of PVP are added to ethanol, and the mixture is ball-milled to obtain a mixing aid; Step 2: Dissolve 4-6 parts by weight of Ni(NO3)2·6H2O in ethanol, add the nano-sized petroleum coke particles prepared in step 1 after ultrasonic dispersion, mix well, then add the mixing aid prepared in step 1, and spray dry to obtain a uniform composite powder; Step 3: cold isostatic pressing the uniform composite powder obtained in step 2 at a pressure of 250-350 MPa for 20-40 min; Step 4: Heat the temperature to 550-650℃ at a rate of 5℃ / min, and then cool naturally to room temperature; Step 5: Under argon protection, heat the mixture to 800-1200°C at a rate of 10°C / min and keep the temperature for 1.5-2.5 hours; Step 6: heating the mixture to 1600-2000°C at a rate of 15°C / min and keeping the temperature for 3-5 hours to obtain a crude graphitized product; Step 7: Cooling to 1000-1200°C, introducing reaction gas containing methane, cracking for 1.5-2.5 hours, so that the cracked carbon is deposited on the surface of the graphitized crude product, and naturally cooling to room temperature to obtain a finished carbon material; In step 7, the reaction gas is a mixture 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; The curvature of the finished carbon material is 29.12-32 MPa; The curvature of the stone is calculated by the following formula: Stone curvature = graphitization degree * average flexural strength; Average bending strength = (upper surface bending strength + side bending strength) / 2; The test method of the graphitization degree is XRD diffraction method, which is calculated using Franklin formula; The testing standard for the flexural strength is JB / T 8133.7-2013.

2. The method for preparing the carbon material according to claim 1, wherein: The D50 of the nano-sized petroleum coke particles in step 1 is 200 nm.

3. The method for preparing a carbon material according to claim 2, wherein: The length of the chopped carbon fibers in step 1 is 3 mm and the diameter is 7 μm.

4. A carbon material, characterized in that: The carbon material is prepared using the method for preparing the carbon material according to any one of claims 1 to 3.

5. A carbon material according to claim 4, characterized in that: The carbon material has a curvature of 30 to 32 MPa.