Preparation and Application of a High-Performance Asphalt-Based Porous Carbon Material

Abstract

The present invention belongs to the technical fields of electrochemistry and energy materials, and particularly relates to the preparation and application of a high-performance pitch-based porous carbon material. The preparation method sequentially includes the following steps: pulverization, heat treatment, pre-oxidation, air-flow pulverization, carbonization, activation, pickling and water washing, and drying. Compared with the prior art, the beneficial effects of the present invention at least include: without using relatively high-cost raw materials such as carbon nanotubes and graphene while ensuring a sufficient specific surface area and a sufficient pore volume value, the preparation method has prominent advantages of simplicity and economy.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemistry and energy materials, and in particular relates to the preparation and application of a high-performance asphalt-based porous carbon material. Background Art

[0002] The negative electrode materials of lithium batteries mainly include carbon-based materials, oxide-based materials, phosphorus-based materials, and silicon-based materials. Among them, the advantage of silicon-based materials is mainly high theoretical specific capacity, and its disadvantage is mainly serious volume expansion during charging and discharging.

[0003] On the other hand, one of the common silicon-based materials is silicon carbon, and the common silicon carbon material mainly refers to vapor-deposited silicon carbon. The core steps of the preparation method of vapor-deposited silicon carbon mainly include: preparation of porous carbon, silane deposition of nano-silicon particles, and carbon layer coating.

[0004] Correspondingly, one of the necessary conditions for vapor-deposited silicon carbon to achieve higher charge and discharge efficiency and better cycle stability is that the above-mentioned porous carbon material must have: a larger specific surface area and a larger pore volume.

[0005] In addition, one of the common raw materials of the above-mentioned porous carbon material is asphalt, and the fundamental purpose of the preparation method of the porous carbon material is to perform sufficient and appropriate pore-making operations on the asphalt.

[0006] For example, a Chinese invention patent application with application publication number CN118206115A and application publication date 2024.06.18 discloses a method for preparing a high-performance asphalt-based porous carbon material, the steps of which include: mixing asphalt and carbon nanotubes to obtain a precursor; pretreating and crushing the obtained precursor; adding graphene and drying; pre-oxidation treatment; carbonization and activation treatment.

[0007] The high-performance asphalt-based porous carbon material in this invention patent application has the following advantages: it has a higher micropore volume and specific surface area, can provide more active sites for chemical vapor deposition of silicon, and improves deposition efficiency.

[0008] However, the above preparation method still has at least the following shortcomings in actual implementation, namely:

[0009] Its total pore volume is 0.68-0.88cm 3 / g, with a specific surface area of ​​1320 m 2 / g or more. On this basis, its raw material composition includes carbon nanotubes and graphene, which are relatively expensive, so the preparation method is not economical and efficient enough. Summary of the invention

[0010] The present invention provides a method for preparing a high-performance asphalt-based porous carbon material. The technical problem to be solved is: how to more simply and economically increase the specific surface area and pore volume of the asphalt so that the product meets the performance requirements of the vapor phase deposition silicon carbon process for the porous carbon raw material.

[0011] In addition, the present invention also provides the above material and application of the above material.

[0012] The technical solution adopted by the present invention to solve the above problems is: a method for preparing a high-performance asphalt-based porous carbon material, which comprises the following steps in sequence:

[0013] S1. Crushing: crushing the asphalt raw material to 200 mesh to obtain crushed material;

[0014] S2. Heat treatment: heat treating the crushed material under a nitrogen atmosphere until the light component content in the crushed material is 45-72 wt % to obtain a precursor;

[0015] S3, pre-oxidation: in a high-temperature carbonization furnace, the precursor is oxidized to obtain a pre-oxidized material;

[0016] S4, air flow crushing: the pre-oxidized material is subjected to air flow crushing operation to crush it to D50=5-8μm to obtain a granular material;

[0017] S5, carbonization: in a high-temperature carbonization furnace, carbonizing the granular material to obtain a carbonized product;

[0018] S6, activation: the carbonized product remains in the high-temperature carbonization furnace, and an alkaline activator is added to perform an activation operation to obtain an activated product;

[0019] S7, acid washing and water washing: the activated product is subjected to several groups of acid washing and water washing operations in sequence to obtain a washing material:

[0020] S8, drying: performing hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material.

[0021] In S4 of the present invention, the air flow pulverization operation is used to control the particle size and improve the comprehensive performance of the material.

[0022] Too small a particle size (<5 μm) will result in a low overall compaction density of the subsequently prepared porous carbon material, which will further result in a low compaction density of the prepared silicon-carbon negative electrode material, ultimately reducing the energy density of the silicon-carbon negative electrode material.

[0023] However, overly large particle sizes (>8 μm) will result in overly large particle sizes of the prepared porous carbon materials, affecting the diffusion of silane gas during the chemical vapor deposition process and reducing the deposition efficiency. Therefore, the particle size range of D50 = 5 - 8 μm as described above was finally determined.

[0024] Among them, the light components refer to organic compounds such as wax, oil, and solvents in asphalt, which are light in nature and volatile. These light components have a significant impact on important properties of asphalt such as viscosity, temperature sensitivity, and oxidation resistance.

[0025] A further preferred technical solution is that in S2, the heat treatment temperature is 150 - 550 °C, and the time is 30 - 300 min.

[0026] A further preferred technical solution is that in S3, the atmosphere for the oxidation operation is oxygen or air, the oxidation temperature is 150 - 400 °C, and the oxidation time is 2 - 5 h.

[0027] A further preferred technical solution is that in S5, the temperature for the carbonization operation is 400 - 1000 °C, the constant-temperature carbonization time is 2 - 4 h, and the heating rate from room temperature to the carbonization temperature is 2 - 7 °C / min.

[0028] A further preferred technical solution is that in S6, the alkaline activator is any one or a mixture of two of potassium hydroxide and sodium hydroxide.

[0029] A further preferred technical solution is that in S6, the weight ratio of the alkaline activator to the carbonized product is (1 - 4)∶1, the atmosphere for the activation operation is nitrogen, the activation temperature is 600 - 1000 °C, and the activation time is 1 - 2 h.

[0030] A further preferred technical solution is that in S7, pickling is carried out using dilute hydrochloric acid, and the combined number of repetitions of pickling and water washing is ≥3 times.

[0031] A further preferred technical solution is that in S8, the end point of the hot air drying operation is that the moisture content of the washed material is ≤0.03 wt%.

[0032] A high-performance asphalt-based porous carbon material prepared by the above preparation method: The high-performance asphalt-based porous carbon material has a hierarchical pore structure, and the hierarchical pore structure includes micropores, mesopores, and macropores. The pore diameter of the micropores <2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores >50 nm.

[0033] An application of the high-performance asphalt-based porous carbon material: The high-performance asphalt-based porous carbon material is used to prepare the negative electrodes of lithium-ion batteries, sodium-ion batteries, and supercapacitors.

[0034] Compared with the prior art, the beneficial effects of the present invention at least include:

[0035] First, without using relatively high-cost raw materials such as carbon nanotubes and graphene while ensuring a sufficient specific surface area and sufficient pore volume values, the preparation method of the high-performance asphalt-based porous carbon material has outstanding advantages of simplicity and economy;

[0036] Second, the specific surface area of the high-performance asphalt-based porous carbon material can reach more than 2500 m 2 / g, and the pore volume can reach more than 1.1 cm 3 / g, which is significantly higher than that of common existing asphalt-based porous carbon materials;

[0037] Third, while ensuring a relatively large pore volume value, the high-performance asphalt-based porous carbon material has a hierarchical pore structure, which includes micropores, mesopores, and macropores. The pore diameter of the micropores is <2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores is >50 nm. The above hierarchical pore structure shows that the porous carbon material has the advantages of rich and comprehensive pore structures, which can ultimately improve the electrical conductivity of the silicon-carbon negative electrode.

[0038] Fourth, in the above hierarchical pore structure, the high-performance asphalt-based porous carbon material also has a relatively higher microporosity, that is, the hierarchical pore structure is mostly micropores. Therefore, it is more conducive to improving the pore volume parameters of the porous carbon material itself and the electrical conductivity of the corresponding silicon-carbon negative electrode. Description of the Drawings

[0039] Figure 1 It is the electron microscope photograph of the final high-performance asphalt-based porous carbon material in Example 1 of the present invention.

[0040] Figure 2 It is the electron microscope photograph of the final high-performance asphalt-based porous carbon material in Example 2 of the present invention.

[0041] Figure 3 It is the electron microscope photograph of the final high-performance asphalt-based porous carbon material in Example 3 of the present invention.

[0042] Figure 4 It is the electron microscope photograph of the final high-performance asphalt-based porous carbon material in Example 4 of the present invention.

[0043] Figure 5 It is the electron microscope photograph of the final high-performance asphalt-based porous carbon material in Example 5 of the present invention. Detailed Embodiments

[0044] The following are only the preferred embodiments of the present invention and do not limit the scope of the present invention.

[0045] Example 1

[0046] As Figure 1 shown, a preparation method of a high-performance asphalt-based porous carbon material successively includes the following steps:

[0047] S1. Crushing: Crushing the asphalt raw material to 200 mesh to obtain a crushed material;

[0048] S2. Heat treatment: Under a nitrogen atmosphere, heat-treating the crushed material until the content of light components in the crushed material is 58 wt%, to obtain a precursor. Among them, the heat treatment temperature is 300 °C and the time is 45 min;

[0049] S3. Pre-oxidation: In a high-temperature carbonization furnace, performing an oxidation operation on the precursor to obtain a pre-oxidized material. Among them, the atmosphere of the oxidation operation is oxygen, the oxidation temperature is 270 °C, and the oxidation time is 3.5 h;

[0050] S4. Jet milling: Performing a jet milling operation on the pre-oxidized material to crush it to D50 = 7 μm to obtain a granular material;

[0051] S5. Carbonization: In a high-temperature carbonization furnace, performing a carbonization operation on the granular material to obtain a carbonized product. Among them, the carbonization operation temperature is 600 °C, the constant-temperature carbonization time is 4 h, and the heating rate from room temperature to the carbonization temperature is 5 °C / min;

[0052] S6. Activation: The carbonized product remains in the high-temperature carbonization furnace, and an alkaline activator is added to perform an activation operation to obtain an activated product. Among them, the alkaline activator is potassium hydroxide, and its weight ratio to the carbonized product is 3:1. The atmosphere of the activation operation is nitrogen, the activation temperature is 850 °C, and the activation time is 1.5 h;

[0053] S7. Acid washing and water washing: Sequentially performing multiple acid washing and water washing operations on the activated product to obtain a washed material. Among them, dilute hydrochloric acid is used for acid washing, and distilled water is used for water washing;

[0054] S8. Drying: Performing a hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. Among them, the end point of the hot air drying operation is that the moisture content of the washed material ≤ 0.03 wt%.

[0055] The high-performance asphalt-based porous carbon material has a hierarchical pore structure, and the hierarchical pore structure includes micropores, mesopores, and macropores. The pore diameter of the micropores < 2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores > 50 nm.

[0056] Application of the high-performance asphalt-based porous carbon material: It is used for preparing the negative electrodes of lithium-ion batteries, sodium-ion batteries, and supercapacitors.

[0057] Example 2

[0058] As Figure 2 shown, a preparation method of a high-performance asphalt-based porous carbon material successively includes the following steps:

[0059] S1. Crushing: Crushing the asphalt raw material to 200 meshes to obtain a crushed material;

[0060] S2. Heat treatment: Under a nitrogen atmosphere, performing heat treatment on the crushed material until the content of light components in the crushed material is 46 wt%, to obtain a precursor. Among them, the heat treatment temperature is 300 °C and the time is 70 min;

[0061] S3. Pre-oxidation: In a high-temperature carbonization furnace, performing an oxidation operation on the precursor to obtain a pre-oxidized material. Among them, the atmosphere of the oxidation operation is air, the oxidation temperature is 270 °C, and the oxidation time is 3.5 h;

[0062] S4. Jet milling: Performing a jet milling operation on the pre-oxidized material to crush it to D50 = 7 μm to obtain a granular material;

[0063] S5. Carbonization: In a high-temperature carbonization furnace, performing a carbonization operation on the granular material to obtain a carbonized product. Among them, the temperature of the carbonization operation is 600 °C, the constant-temperature carbonization time is 4 h, and the heating rate from room temperature to the carbonization temperature is 5 °C / min;

[0064] S6. Activation: The carbonized product remains in the high-temperature carbonization furnace, and an alkaline activator is added to perform an activation operation to obtain an activated product. Among them, the alkaline activator is potassium hydroxide, and its weight ratio to the carbonized product is 3:1. The atmosphere of the activation operation is nitrogen, the activation temperature is 850 °C, and the activation time is 1.5 h;

[0065] S7. Acid washing and water washing: Sequentially performing multiple acid washing and water washing operations on the activated product to obtain a washed material. Among them, dilute hydrochloric acid is used for acid washing, and distilled water is used for water washing;

[0066] S8. Drying: Performing a hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. Among them, the end point of the hot air drying operation is that the moisture content of the washed material ≤ 0.03 wt%.

[0067] The high-performance asphalt-based porous carbon material has a hierarchical pore structure. The hierarchical pore structure includes micropores, mesopores, and macropores. The pore diameter of the micropores < 2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores > 50 nm.

[0068] Application of the high-performance asphalt-based porous carbon material: It is used for preparing the negative electrodes of lithium-ion batteries, sodium-ion batteries and supercapacitors.

[0069] Example 3

[0070] As Figure 3 shown, a preparation method of a high-performance asphalt-based porous carbon material successively includes the following steps.

[0071] S1. Crushing: Crushing the asphalt raw material to 200 meshes to obtain a crushed material.

[0072] S2. Heat treatment: Under a nitrogen atmosphere, performing heat treatment on the crushed material until the content of light components in the crushed material is 67 wt%, to obtain a precursor. Among them, the heat treatment temperature is 300 °C and the time is 30 min.

[0073] S3. Pre-oxidation: In a high-temperature carbonization furnace, performing an oxidation operation on the precursor to obtain a pre-oxidized material. Among them, the atmosphere of the oxidation operation is air, the oxidation temperature is 270 °C, and the oxidation time is 3.5 h.

[0074] S4. Jet milling: Performing a jet milling operation on the pre-oxidized material to crush it to D50 = 7 μm to obtain a granular material.

[0075] S5. Carbonization: In a high-temperature carbonization furnace, performing a carbonization operation on the granular material to obtain a carbonized product. Among them, the temperature of the carbonization operation is 600 °C, the constant-temperature carbonization time is 4 h, and the heating rate from room temperature to the carbonization temperature is 5 °C / min.

[0076] S6. Activation: The carbonized product remains in the high-temperature carbonization furnace, and an alkaline activator is added to perform an activation operation to obtain an activated product. Among them, the alkaline activator is potassium hydroxide, and its weight ratio to the carbonized product is 3:1. The atmosphere of the activation operation is nitrogen, the activation temperature is 850 °C, and the activation time is 1.5 h.

[0077] S7. Pickling and water washing: Sequentially performing multiple pickling and water washing operations on the activated product to obtain a washed material. Among them, dilute hydrochloric acid is used for pickling operation, and distilled water is used for water washing operation.

[0078] S8. Drying: Performing a hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. Among them, the end point of the hot air drying operation is that the moisture content of the washed material ≤ 0.03 wt%.

[0079] The high-performance asphalt-based porous carbon material has a hierarchical pore structure. The hierarchical pore structure includes micropores, mesopores and macropores. The pore diameter of the micropores < 2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores > 50 nm.

[0080] Application of the high-performance asphalt-based porous carbon material: It is used for preparing the negative electrodes of lithium-ion batteries, sodium-ion batteries and supercapacitors.

[0081] Example 4

[0082] As Figure 4 shown, a preparation method of a high-performance asphalt-based porous carbon material successively includes the following steps.

[0083] S1. Crushing: Crushing the asphalt raw material to 200 meshes to obtain a crushed material.

[0084] S2. Heat treatment: Under a nitrogen atmosphere, performing heat treatment on the crushed material until the content of light components in the crushed material is 58 wt%, to obtain a precursor. Among them, the temperature of the heat treatment is 300 °C and the time is 45 min.

[0085] S3. Pre-oxidation: In a high-temperature carbonization furnace, performing an oxidation operation on the precursor to obtain a pre-oxidized material. Among them, the atmosphere of the oxidation operation is air, the oxidation temperature is 270 °C, and the oxidation time is 3.0 h.

[0086] S4. Jet milling: Performing a jet milling operation on the pre-oxidized material to crush it to D50 = 7 μm to obtain a granular material.

[0087] S5. Carbonization: In a high-temperature carbonization furnace, performing a carbonization operation on the granular material to obtain a carbonized product. Among them, the temperature of the carbonization operation is 900 °C, the constant-temperature carbonization time is 4 h, and the heating rate from room temperature to the carbonization temperature is 5 °C / min.

[0088] S6. Activation: Keeping the carbonized product in the high-temperature carbonization furnace, adding an alkaline activator, and performing an activation operation to obtain an activated product. Among them, the alkaline activator is potassium hydroxide, and its weight ratio to the carbonized product is 3:1. The atmosphere of the activation operation is nitrogen, the activation temperature is 850 °C, and the activation time is 1.5 h.

[0089] S7. Acid washing and water washing: Sequentially performing multiple acid washing and water washing operations on the activated product to obtain a washed material. Among them, dilute hydrochloric acid is used for the acid washing operation, and distilled water is used for the water washing operation.

[0090] S8. Drying: Performing a hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. Among them, the end point of the hot air drying operation is that the moisture content of the washed material ≤ 0.03 wt%.

[0091] This high-performance asphalt-based porous carbon material has a hierarchical pore structure, which includes micropores, mesopores, and macropores. The pore diameter of the micropores is <2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores is >50 nm.

[0092] Application of this high-performance asphalt-based porous carbon material: It is used to prepare the negative electrodes of lithium-ion batteries, sodium-ion batteries, and supercapacitors.

[0093] Example 5

[0094] As Figure 5 shown, a preparation method of a high-performance asphalt-based porous carbon material successively includes the following steps:

[0095] S1. Crushing: Crush the asphalt raw material to 200 mesh to obtain a crushed material.

[0096] S2. Heat treatment: Under a nitrogen atmosphere, perform heat treatment on the crushed material until the content of light components in the crushed material is 58 wt%, to obtain a precursor. Among them, the heat treatment temperature is 300 °C and the time is 45 min.

[0097] S3. Pre-oxidation: In a high-temperature carbonization furnace, perform an oxidation operation on the precursor to obtain a pre-oxidized material. Among them, the atmosphere of the oxidation operation is air, the oxidation temperature is 270 °C, and the oxidation time is 3.0 h.

[0098] S4. Jet milling: Perform a jet milling operation on the pre-oxidized material to crush it to D50 = 7 μm to obtain a granular material.

[0099] S5. Carbonization: In a high-temperature carbonization furnace, perform a carbonization operation on the granular material to obtain a carbonized product. Among them, the temperature of the carbonization operation is 600 °C, the constant-temperature carbonization time is 4 h, and the heating rate from room temperature to the carbonization temperature is 5 °C / min.

[0100] S6. Activation: Leave the carbonized product in the high-temperature carbonization furnace, add an alkaline activator, and perform an activation operation to obtain an activated product. Among them, the alkaline activator is potassium hydroxide, and its weight ratio to the carbonized product is 2:1. The atmosphere of the activation operation is nitrogen, the activation temperature is 850 °C, and the activation time is 1.5 h.

[0101] S7. Acid washing and water washing: Perform multiple acid washing and water washing operations on the activated product in sequence to obtain a washed material. Among them, dilute hydrochloric acid is used for acid washing, and distilled water is used for water washing.

[0102] S8. Drying: Perform a hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. Among them, the end point of the hot air drying operation is that the moisture content of the washed material ≤ 0.03 wt%.

[0103] The high-performance asphalt-based porous carbon material has a hierarchical pore structure, and the hierarchical pore structure includes micropores, mesopores, and macropores. The pore diameter of the micropores is <2 nm, the pore diameter of the mesopores is 2 - 50 nm, and the pore diameter of the macropores is >50 nm.

[0104] Application of the high-performance asphalt-based porous carbon material: It is used for preparing the negative electrodes of lithium-ion batteries, sodium-ion batteries, and supercapacitors.

[0105] Comparative Example 1

[0106] The high-performance asphalt-based porous carbon material, its preparation method, and application in this comparative example have only the following 1 difference compared with Example 1:

[0107] In S2, the heat treatment operation has a relatively short time and a relatively low temperature, and the content of light components in the crushed material is 77.5 wt%.

[0108] Comparative Example 2

[0109] The high-performance asphalt-based porous carbon material, its preparation method, and application in this comparative example have only the following 1 difference compared with Example 1:

[0110] In S4, the D50 of the granular material is 55.0 μm.

[0111] Comparative Example 3

[0112] The high-performance asphalt-based porous carbon material, its preparation method, and application in this comparative example have only the following 1 difference compared with Example 1:

[0113] Neither the step of S6, activation, nor the step of S7, pickling and water washing, is carried out. That is, after the carbonized product is taken out of the high-temperature carbonization furnace, hot air drying operation is carried out as required to obtain the final high-performance asphalt-based porous carbon material.

[0114] Comparative Example 4

[0115] The high-performance asphalt-based porous carbon material, its preparation method, and application in this comparative example have only the following 1 difference compared with Example 1:

[0116] The step of S7, pickling and water washing, is not carried out. That is, the activated product is directly subjected to hot air drying operation to obtain the final high-performance asphalt-based porous carbon material.

[0117] Comparative Example 5

[0118] The high-performance asphalt-based porous carbon material, its preparation method, and application in this comparative example have only the following 1 difference compared with Example 1:

[0119] In S8, the drying time is relatively short, and the water content of the washed material is 0.05 - 0.06 wt%.

[0120] Parameter measurement

[0121] In the above 5 examples and 5 comparative examples, 10 samples were taken respectively for parameter measurement, and the average value was finally taken and recorded in the following table.

[0122] Specific surface area (m² / g) Micropore specific surface area (m² / g) Pore ​​volume (cm³ / g) Micropore volume (cm³ / g) Average pore size (nm) Microporosity (%) Example 1 2586.35 2323.28 1.168 0.941 1.81 80.52 Example 2 2419.67 2032.10 1.063 0.806 1.76 75.80 Example 3 1931.51 1531.57 0.896 0.631 1.85 70.33 Example 4 890.25 747.05 0.422 0.295 1.90 69.79 Example 5 1326.90 1106.50 0.563 0.433 1.69 76.88 Comparative Example 1 1767.85 909.52 0.659 0.350 1.78 53.21 Comparative Example 2 1478.02 1255.29 0.626 0.494 1.69 78.91 Comparative Example 3 459.52 335.23 0.220 0.131 2.52 59.80 Comparative Example 4 850.20 665.24 0.502 0.322 2.22 65.30 Comparative Example 5 1800.85 1296.88 1.108 0.759 1.98 68.52

[0123] Data analysis

[0124] First, the porous carbon materials in Examples 1, 2, and 3 have relatively large specific surface areas and pore volumes, and the hierarchical pore structures are mostly micropores, so it is more conducive to the electrical conductivity of their corresponding silicon-carbon anodes.

[0125] Second, the parameters of the porous carbon materials in Examples 4 and 5 are significantly inferior to those in Examples 1, 2, and 3. The reason may be that too high carbonization temperature and too little alkali dosage are not conducive to the activation of the materials.

[0126] Third, compared with Examples 1, 2, and 3, the porous carbon materials in Comparative Examples 1 - 5 all have the problems of relatively small specific surface area and pore volume to a certain extent. Therefore, conversely, it proves the necessity and importance of the original defined ranges corresponding to the differences compared with Example 1 in each comparative example.

[0127] Fourth, in Comparative Examples 1 - 5, the one with the smallest specific surface area and pore volume is Comparative Example 3, which verifies the extremely important of these two steps of activation and pickling and water washing.

[0128] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art in the said technical field, various modifications can be made without departing from the purpose of the present invention. These are all non-creative modifications and are protected by the patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for preparing a high-performance asphalt-based porous carbon material, characterized in that The following steps are included in sequence: S1. Crushing: crushing the asphalt raw material to 200 mesh to obtain crushed material; S2. Heat treatment: heat treating the crushed material under a nitrogen atmosphere until the light component content in the crushed material is 46-67 wt % to obtain a precursor; S3, pre-oxidation: in a high-temperature carbonization furnace, the precursor is oxidized to obtain a pre-oxidized material; S4, air flow crushing: the pre-oxidized material is subjected to air flow crushing operation to crush it to D50=5-8μm to obtain a granular material; S5, carbonization: in a high-temperature carbonization furnace, carbonizing the granular material to obtain a carbonized product; S6, activation: the carbonized product remains in the high-temperature carbonization furnace, and an alkaline activator is added to perform an activation operation to obtain an activated product; S7, acid washing and water washing: the activated product is subjected to several groups of acid washing and water washing operations in sequence to obtain a washing material: S8, drying: performing hot air drying operation on the washed material to obtain the final high-performance asphalt-based porous carbon material. In S2, the heat treatment temperature is 300-550°C and the time is 30-300 minutes. The light components include wax, oil and solvent in asphalt, In S6, the alkaline activator is any one of potassium hydroxide and sodium hydroxide or a mixture of the two. In S3, the atmosphere of the oxidation operation is oxygen or air, the oxidation temperature is 150-400°C, and the oxidation time is 2-5h.

2. The method for preparing a high-performance pitch-based porous carbon material according to claim 1, characterized in that: In S5, the temperature of the carbonization operation is 400-600°C, the constant temperature carbonization time is 2-4h, and the heating rate from room temperature to the carbonization temperature is 2-7°C / min.

3. The method for preparing a high-performance pitch-based porous carbon material according to claim 1, characterized in that: In S6, the weight ratio of the alkaline activator to the carbonized product is (3-4):1, the atmosphere of the activation operation is nitrogen, the activation temperature is 600-1000°C, and the activation time is 1-2h.

4. The method for preparing a high-performance pitch-based porous carbon material according to claim 1, characterized in that: In S7, dilute hydrochloric acid is used for pickling operation, and the combination of pickling and water washing is repeated ≥ 3 times.

5. The method for preparing a high-performance pitch-based porous carbon material according to claim 1, characterized in that: In S8, the end point of the hot air drying operation is that the moisture content of the washing material is ≤0.03wt%.

6. A high-performance pitch-based porous carbon material obtained by the preparation method according to any one of claims 1 to 5, characterized in that: The high-performance asphalt-based porous carbon material has a hierarchical pore structure, which includes micropores, mesopores and macropores. The pore size of the micropores is <2nm, the pore size of the mesopores is 2-50nm, and the pore size of the macropores is >50nm.

7. An application of the high-performance asphalt-based porous carbon material as claimed in claim 6, characterized in that: The high-performance asphalt-based porous carbon material is used to prepare negative electrodes of lithium-ion batteries, sodium-ion batteries and supercapacitors.

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