Asphalt-based porous carbon material and preparation method thereof
Through the combination of eutectic solvent and anhydrous metal chloride, the homogeneous dispersion of asphalt in the solvent and the uniform formation of pores is achieved, the porosity and uniformity of porous carbon materials are solved, and the circulation performance of lithium-ion batteries is improved.
Patent Information
- Application Number
- CN202510651041.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, coal asphalt is difficult to disperse homogeneously in solvents, resulting in the low porosity and poor uniformity of pore size of prepared porous carbon materials, which cannot effectively solve the problem of cyclic performance attenuation caused by volume expansion of silicon-based materials in lithium-ion batteries.
The eutectic solvent is used to form hydrogen bond donor and hydrogen bond acceptor. The hydrogen bond network in the asphalt molecule is broken through hydrogen bonding, so that it is homogeneously dispersed in the solvent, and pores are formed during the carbonization process using anhydrous metal chloride as a template agent to prepare porous carbon materials.
The prepared porous carbon material has a high porosity and a relatively uniform pore size, which improves the cycling stability and conductivity of silicon-based materials in lithium-ion batteries.
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Figure CN120328531A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of materials manufacturing for secondary batteries, and more particularly, to an asphalt-based porous carbon material and a preparation method thereof. Background Art
[0002] The rapid development of large-scale energy storage and the electric vehicle industry requires lithium-ion batteries to have higher energy density and cycle stability. Silicon-based materials have a high specific capacity (3600 mAh / g), abundant reserves, and a low lithium intercalation voltage, and are considered to be one of the anode materials for lithium-ion batteries with the best commercial prospects. However, silicon-based materials have problems of severe volume expansion and poor conductivity during the cycling process, resulting in the destruction of the corresponding electrode structure and thus rapid attenuation of their cycling performance. On this basis, by developing porous carbon materials as carriers and loading silicon-based materials into the pores of porous carbon materials, the problems brought by the application of silicon-based materials can be effectively solved. Among them, coal tar pitch has the advantages of wide source, low cost, high fixed carbon content (up to 57.5%) and low ash content (about 0.16%), and is the preferred carbon source for preparing porous carbon. However, coal tar pitch contains a large number of aromatic hydrocarbon compounds. Due to the conjugation of polycyclic aromatic hydrocarbons, it is difficult for pitch to be homogeneously dispersed in the solvent, resulting in problems of low porosity and poor pore size uniformity of the formed porous carbon material. Summary of the Invention
[0003] The purpose of this application is to provide an asphalt-based porous carbon material and a preparation method thereof. The porous carbon material prepared by this method has the advantages of high porosity and relatively uniform pore size.
[0004] The embodiments of this application are implemented as follows:
[0005] In a first aspect, an embodiment of this application provides a preparation method of an asphalt-based porous carbon material, including the following steps:
[0006] S1 Mix a hydrogen bond donor and a hydrogen bond acceptor under heating conditions, where the hydrogen bond acceptor includes anhydrous metal chloride, to obtain a deep eutectic solvent.
[0007] S2 Add asphalt to the deep eutectic solvent and sequentially perform mixing treatment and drying treatment to obtain a carbonization precursor.
[0008] S3 Carbonize the carbonization precursor under an inert atmosphere to obtain a porous carbon precursor. S4 Perform pickling treatment and water washing treatment on the porous carbon precursor to obtain an asphalt-based porous carbon material.
[0009] In the above technical solution, an anhydrous metal chloride is used as a hydrogen bond acceptor and a hydrogen bond donor to form a deep eutectic solvent (DES). On the one hand, the deep eutectic solvent has the characteristics of hydrogen bond donors and acceptors, and there are strong hydrogen bond interactions between molecules. It can form hydrogen bond interactions with hydroxyl groups, carboxyl groups, etc. in asphalt, which helps to break the hydrogen bonds within asphalt molecules and has a significant deconstruction effect on asphalt containing a hydrogen bond network, so that asphalt can be homogeneously dispersed in the DES. On the other hand, the hydrogen bond acceptor in the DES that binds to asphalt molecules through hydrogen bonds is an anhydrous metal chloride, which can act as a templating agent for pore formation (that is, the DES also has the function of acting as a templating agent), so that pores can be formed in the corresponding regions of the material during carbonization and pickling. Through the combined action of the two aspects, asphalt can be homogeneously dispersed in the solvent, and the asphalt molecules in the carbonization precursor have a uniformly dispersed templating agent that can assist in pore formation. Furthermore, the porous carbon material prepared by this method has the advantages of a relatively high porosity and relatively uniform pore sizes.
[0010] In some alternative embodiments, the hydrogen bond donor includes a polyol having 2 to 5 carbon atoms, and / or the anhydrous metal chloride is selected from at least one of zinc chloride, aluminum chloride, and iron chloride.
[0011] In the above technical solution, using a polyol with the above number of carbon atoms has the advantage of relatively small steric hindrance between molecules, which is convenient for forming a deep eutectic solvent with a hydrogen bond acceptor. At the same time, there are many applicable types of anhydrous metal chlorides, which can provide more feasible implementation schemes, thus facilitating the popularization and application of the technical solution provided by the embodiments of the present application.
[0012] In some alternative embodiments, the polyol is selected from at least one of ethylene glycol, glycerol, 1,3 - propanediol, 1,4 - butanediol, pentaerythritol, and neopentyl glycol.
[0013] In the above technical solution, there are many applicable types of polyols, which can provide more feasible implementation schemes, thus facilitating the popularization and application of the technical solution provided by the present application.
[0014] In some alternative embodiments, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:(0.1 - 5).
[0015] In the above technical solution, after the types of the hydrogen bond acceptor and the hydrogen bond donor are determined, limiting the molar ratio of the two within the above range helps the hydrogen bond acceptor and the hydrogen bond donor to fully react to form a deep eutectic solvent.
[0016] In some alternative embodiments, the lowest melting point of the components in the hydrogen bond donor is M1, and the lowest melting point of the components in the hydrogen bond acceptor is M2. In the step of mixing the hydrogen bond donor and the hydrogen bond acceptor under heating conditions, the heating temperature is T, where T satisfies the relational expression:
[0017] In the above technical solution, after the lowest melting points of the components in the hydrogen bond donor and the hydrogen bond acceptor are determined, setting the heating temperature T through the above relational expression helps to improve the preparation efficiency of the deep eutectic solvent.
[0018] In some alternative embodiments, the mass ratio of asphalt to the deep eutectic solvent is 1:(1 - 30).
[0019] In the above technical solution, limiting the mass ratio of asphalt to the deep eutectic solvent within the above range helps the uniform dispersion of asphalt. At the same time, it can also graft an appropriate amount of DES on the surface of asphalt by forming hydrogen bonds, which helps the carbonization precursor to form pores during subsequent carbonization and pickling processes.
[0020] In some alternative embodiments, the softening point of asphalt is 120 - 250 °C.
[0021] In the above technical solution, using asphalt with a lower softening point has the advantages of less energy consumption and higher safety because the corresponding carbonization temperature for a lower softening point is also lower.
[0022] In some alternative embodiments, the step of carbonizing the carbonization precursor under an inert atmosphere includes: heating the carbonization precursor under an inert atmosphere, and then maintaining the temperature constant for heat preservation carbonization treatment. In the step of heating treatment, the heating rate is 3 - 5 °C / min, and / or in the step of heat preservation carbonization treatment, the treatment temperature is 600 - 1000 °C, and the treatment time is 2 - 4 h.
[0023] In the above technical solution, limiting the heating rate in the heating treatment stage and the treatment temperature and duration in the heat preservation carbonization stage within the above ranges helps the carbonization precursor to be fully carbonized.
[0024] In some alternative embodiments, the inert atmosphere is selected from at least one of nitrogen and argon, and / or the gas flow rate of the inert atmosphere is 20 - 50 mL / min.
[0025] In the above technical solution, there are many types of inert atmospheres, which can provide more alternative embodiments; at the same time, limiting the gas flow rate within the above range can provide a better inert atmosphere and maintain the stability of the temperature and pressure in the container during gas flow transportation, thereby providing a better carbonization environment.
[0026] In a second aspect, an asphalt-based porous carbon material provided by an embodiment of the present application is prepared by using the preparation method provided by the embodiment of the first aspect.
[0027] In the above technical solution, the asphalt-based porous carbon material is prepared by using the preparation method provided by the embodiment of the first aspect. Since the eutectic solvent used can effectively disperse asphalt and act as a templating agent, the prepared asphalt-based porous carbon material has the advantages of a lower porosity and relatively uniform pore sizes. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.
[0029] Figure 1 It is a process flow diagram of a preparation method of an asphalt-based porous carbon material provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchases.
[0031] It should be noted that "and / or" in the present application, such as "feature 1 and / or feature 2", refers to three cases: "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".
[0032] In addition, in the description of the present application, unless otherwise specified, "multiple" in "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two end values "a" and "b", and the "measurement unit" in "numerical value a to numerical value b + measurement unit" represents the "measurement unit" of both "numerical value a" and "numerical value b".
[0033] The following specifically describes an asphalt-based porous carbon material and its preparation method according to an embodiment of the present application.
[0034] In a first aspect, an embodiment of the present application provides a preparation method of an asphalt-based porous carbon material, including the following steps:
[0035] S1 Mix a hydrogen bond donor and a hydrogen bond acceptor under heating conditions, where the hydrogen bond acceptor includes anhydrous metal chloride, to obtain a deep eutectic solvent.
[0036] S2 Add asphalt to the deep eutectic solvent and successively perform mixing treatment and drying treatment to obtain a carbonization precursor.
[0037] S3 Carbonize the carbonization precursor under an inert atmosphere to obtain a porous carbon precursor.
[0038] S4 Perform pickling treatment and water washing treatment on the porous carbon precursor to obtain an asphalt-based porous carbon material.
[0039] It should be noted that as a new generation of green solvent, deep eutectic solvent (DES) is a eutectic mixture of two or more components formed by hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA) through intermolecular hydrogen bonding, and its eutectic point is lower than the melting point of any single component.
[0040] It should be noted that since the deep eutectic solvent and asphalt are combined through hydrogen bonding, the drying treatment will not remove all the solvent, so the obtained carbonization precursor is viscous.
[0041] In this application, anhydrous metal chloride is used as the hydrogen bond acceptor and the hydrogen bond donor to form a deep eutectic solvent (DES). On the one hand, the deep eutectic solvent has the characteristics of hydrogen bond donor-acceptor, and there is a strong intermolecular hydrogen bond, which can form hydrogen bonds with hydroxyl groups, carboxyl groups, etc. in asphalt, helping to break the hydrogen bonds within asphalt molecules and having a significant deconstruction effect on asphalt containing a hydrogen bond network, so that asphalt can be homogeneously dispersed in DES. On the other hand, the hydrogen bond acceptor in DES that binds to asphalt molecules through hydrogen bonds is anhydrous metal chloride, which can act as a pore-forming template agent (that is, DES also has the role of acting as a template agent), so that pores are formed in the corresponding regions of the material during carbonization and pickling. Through the combined action of the two aspects, asphalt can be homogeneously dispersed in the solvent and the asphalt molecules in the carbonization precursor have a uniformly dispersed template agent that can assist in pore formation, so that the porous carbon material prepared by this method has the advantages of low porosity and relatively uniform pore size.
[0042] As an example, before the mixing treatment, it also includes the step of crushing the asphalt.
[0043] As an example, in the drying process, the drying temperature is 70 to 90 °C. For example, but not limited to, the drying temperature can be any one of the point values of 70 °C, 75 °C, 80 °C, 85 °C, and 90 °C or the range value between any two of them; the drying time is 8 to 12 h. For example, but not limited to, the drying time can be any one of the point values of 8 h, 9 h, 10 h, 11 h, and 12 h or the range value between any two of them.
[0044] It should be noted that the types of hydrogen bond donors are not limited. In principle, as long as they can form a deep eutectic solvent with anhydrous metal chlorides.
[0045] As an example, the hydrogen bond donor includes a polyol with 2 to 5 carbon atoms, and / or the anhydrous metal chloride is selected from at least one of zinc chloride, aluminum chloride, and iron chloride.
[0046] In this embodiment, using the polyol with the above number of carbon atoms has the advantage of relatively small steric hindrance between molecules, which is convenient for forming a deep eutectic solvent with the hydrogen bond acceptor; at the same time, there are many applicable types of anhydrous metal chlorides, which can provide more implementation schemes, thus facilitating the popularization and application of the technical solutions provided in the embodiments of the present application.
[0047] As an example, the polyol is selected from at least one of ethylene glycol, glycerol, 1,3 - propanediol, 1,4 - butanediol, pentaerythritol, and neopentyl glycol.
[0048] In this embodiment, there are many applicable types of polyols, which can provide more implementation schemes, thus facilitating the popularization and application of the technical solutions provided in the present application.
[0049] As an example, the molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:(0.1 - 5). For example, but not limited to, the molar ratio can be any one of the point values of 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4, and 1:5 or the range value between any two of them.
[0050] In this embodiment, when the types of the hydrogen bond acceptor and the hydrogen bond donor are determined, limiting the molar ratio of the two within the above range helps the hydrogen bond acceptor and the hydrogen bond donor to fully react to form a deep eutectic solvent.
[0051] As an example, the lowest melting point of the components in the hydrogen bond donor is M1, and the lowest melting point of the components in the hydrogen bond acceptor is M2. In the step of mixing the hydrogen bond donor and the hydrogen bond acceptor under heating conditions, the heating temperature is T, where T satisfies the relationship:
[0052] It should be noted that when there is only one type of hydrogen bond donor and one type of hydrogen bond acceptor, M1 and M2 are respectively the melting points of the corresponding hydrogen bond donor and hydrogen bond acceptor; when the hydrogen bond donor and hydrogen bond acceptor are respectively two or more components, M1 is determined by the hydrogen bond donor component with the lowest melting point, and M2 is determined by the hydrogen bond acceptor component with the lowest melting point.
[0053] In this embodiment, after determining the lowest melting point of the components in the hydrogen bond donor and hydrogen bond acceptor, setting the heating temperature T through the above relational formula helps to improve the preparation efficiency of the deep eutectic solvent.
[0054] As an example, the mass ratio of asphalt to the deep eutectic solvent is 1:(1 - 30), such as but not limited to any one of the mass ratios of 1:1, 1:5, 1:10, 1:15, 1:20, 1:25, and 1:30 or the range value between any two of them.
[0055] In this embodiment, limiting the mass ratio of asphalt to the deep eutectic solvent within the above range helps the uniform dispersion of asphalt. At the same time, by forming hydrogen bonds, an appropriate amount of DES can be grafted onto the surface of asphalt, which helps to form pores during the subsequent carbonization and pickling processes of the carbonization precursor.
[0056] As an example, the softening point of asphalt is 120 - 250 °C, such as but not limited to any one of the softening points of 120 °C, 140 °C, 160 °C, 180 °C, 200 °C, 220 °C, 240 °C, and 250 °C or the range value between any two of them.
[0057] In this embodiment, using asphalt with a lower softening point has the advantages of less energy consumption and higher safety because the corresponding carbonization temperature for a lower softening point is also lower.
[0058] As an example, the steps of carbonizing the carbonization precursor in an inert atmosphere include: heating the carbonization precursor in an inert atmosphere, and then maintaining the temperature constant for heat preservation carbonization. Among them, in the step of heating, the heating rate is 3 - 5 °C / min (such as but not limited to any one of the heating rates of 3 °C / min, 3.5 °C / min, 4 °C / min, 4.5 °C / min, and 5 °C / min or the range value between any two of them), and / or, in the step of heat preservation carbonization, the treatment temperature is 600 - 1000 °C (such as but not limited to any one of the temperatures of 600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C or the range value between any two of them), and the treatment time is 2 - 4 h (such as but not limited to any one of the durations of 2 h, 2.5 h, 3 h, 3.5 h, and 4 h or the range value between any two of them).
[0059] In this embodiment, limiting the heating rate in the heating treatment stage and the treatment temperature and duration in the heat preservation carbonization stage within the above ranges respectively helps the carbonization precursor to be fully carbonized.
[0060] As an example, the inert atmosphere is selected from at least one of nitrogen and argon, or / and, the gas flow rate of the inert atmosphere is 20-50 mL / min. For example, but not limited to, the gas flow rate can be any one of 20 mL / min, 25 mL / min, 30 mL / min, 35 mL / min, 40 mL / min, 45 mL / min and 50 mL / min or the range value between any two of them.
[0061] In this embodiment, there are many types of inert atmospheres, which can provide more implementable solutions; at the same time, limiting the gas flow rate within the above range can provide a better inert atmosphere and maintain the stability of the temperature and pressure in the container during the gas flow transportation, thereby providing a better carbonization environment.
[0062] It should be noted that the steps of the pickling treatment can be selected according to the conventional methods in the art as long as the corresponding metal elements in the porous carbon precursor can be removed.
[0063] It should be noted that the processes or steps that are not specifically described or limited during the preparation process can be set according to the conventional selections in the art.
[0064] As an example, the process flow chart of the preparation method of the pitch-based porous carbon material can be referred to Figure 1 .
[0065] In the second aspect, the embodiments of the present application provide a pitch-based porous carbon material prepared by using the preparation method provided in the first aspect embodiment.
[0066] In the present application, the pitch-based porous carbon material is prepared by using the preparation method provided in the first aspect embodiment. Since the eutectic solvent used can not only effectively disperse the pitch but also act as a template agent, the prepared pitch-based porous carbon material has the advantages of lower porosity and more uniform pore size.
[0067] The features and properties of the present application will be further described in detail below with reference to the embodiments.
[0068] Example 1
[0069] The embodiments of the present application provide a preparation method of a pitch-based porous carbon material, including the following steps:
[0070] S1 Weigh ethylene glycol (hydrogen bond donor) and anhydrous zinc chloride (hydrogen bond acceptor) according to a molar ratio of 1:3 and stir and mix them at 60 °C until the solution is clear and transparent to obtain a eutectic solvent.
[0071] S2 Select coal-based pitch with a softening point of 120 °C, crush it with a crusher and repeat three times, disperse it in the eutectic solvent according to a mass ratio of 1:20, then mechanically stir and mix for 2 h and dry at 80 °C for 12 h to obtain a carbonization precursor.
[0072] S3 Carbonize the carbonization precursor under a nitrogen atmosphere (gas flow rate of 25 mL / min). Specifically, first heat it to 950 °C at a heating rate of 3 °C / min, then keep the temperature constant for heat preservation treatment for 2 h, and take out the carbonized material after the temperature of the reaction equipment drops to 30 °C to obtain a porous carbon precursor.
[0073] S4 Pickle the porous carbon precursor with dilute hydrochloric acid, then wash the pickled material three times with deionized water (i.e., water washing treatment) and perform vacuum drying treatment for 8 h to obtain a dry asphalt-based porous carbon material.
[0074] Comparative Example 1
[0075] The comparative example of this application provides a preparation method of an asphalt-based porous carbon material, and the difference from Example 1 is only that:
[0076] S1 Weigh N-methylpyrrolidone and sodium chloride according to a molar ratio of 1:3 and stir and mix at 60 °C until the solution is clear and transparent.
[0077] S2 Select coal-based pitch with a softening point of 120 °C, crush it with a crusher and repeat three times, disperse it in the solvent obtained in S1 according to a mass ratio of 1:20, then mechanically stir and mix for 2 h and dry at 80 °C for 12 h to obtain a carbonization precursor.
[0078] Comparative Example 2
[0079] The comparative example of this application provides a preparation method of an asphalt-based porous carbon material, and the difference from Example 1 is only that:
[0080] S1 Weigh ethylene glycol (hydrogen bond donor) and choline chloride (hydrogen bond acceptor, without template agent function) according to a molar ratio of 1:3 and stir and mix at 60 °C until the solution is clear and transparent to obtain a eutectic solvent.
[0081] Comparative Example 3
[0082] The comparative example of this application provides a preparation method of an asphalt-based porous carbon material, and the difference from Example 1 is only that:
[0083] S1 Weigh ethylene glycol (hydrogen bond donor) and choline chloride (hydrogen bond acceptor) according to a molar ratio of 1:3 and stir and mix them at 60 °C until the solution becomes clear and transparent to obtain a deep eutectic solvent; then add sodium chloride (the molar amount of sodium chloride is the same as that of anhydrous zinc chloride, the template agent) thereto and stir and mix at 60 °C to obtain a mixed solution.
[0084] S2 Select a coal-based pitch with a softening point of 120 °C, crush it with a crusher and repeat three times, disperse it in the mixed solution obtained in S1 according to a mass ratio of 1:20, then mechanically stir and mix for 2 h and dry at 80 °C for 12 h to obtain a carbonization precursor.
[0085] Test Example
[0086] Performance Test of Porous Carbon Materials
[0087] Test Method:
[0088] Number the pitch-based porous carbon materials prepared in Example 1 and Comparative Examples 1 to 3 respectively, then test the porosity and the uniformity of pore size of each sample, and then summarize the test results in Table 1.
[0089] Among them, (1) the test steps for porosity are as follows:
[0090] S1 Sample pretreatment: Degassing treatment to remove the moisture and impurities adsorbed on the surface of the sample.
[0091] Temperature: Usually 150 - 300 °
[0092] Time: ≥ 6 hours (in a vacuum or inert gas atmosphere).
[0093] Vacuum degree: ≤ 10-3 Torr (or 0.1 Pa).
[0094] Sample amount: 50 - 200 mg
[0095] S2 Sample tube loading: Quickly transfer the degassed sample to a pre-weighed sample tube, avoid exposure to air, and record the weight of the sample tube (accurate to 0.1 mg).
[0096] S3 Measurement of low-temperature nitrogen adsorption curve: Immerse the sample tube in liquid nitrogen (-196 °C), gradually introduce nitrogen through a controllable program, and measure the adsorption amount at different pressures (P / P).
[0097] Relative pressure range: Specific surface area (BET model): 0.05 - 0.3 P / P.
[0098] S4 Measurement of desorption curve: Gradually reduce the pressure, record the desorption data, and form a hysteresis loop (to analyze the mesoporous structure).
[0099] S5 performs software fitting analysis on the curves in S3 and S4 to obtain the porosity, which is then tabulated in Table 1.
[0100] (2) The test steps for the uniformity of pore size are as follows:
[0101] S1 According to the test steps for porosity in (1), the total volume Vtotal can be synchronously measured.
[0102] S2 By combining the curves in steps S3 and S4 in (1) into the DFT model, the micropore volume Vmicro can be fitted.
[0103] S3 According to the formula: mesopore volume Vmeso = Vtotal - Vmicro, the mesopore volume is calculated.
[0104] S4 According to the formula: The mesopore proportion is calculated and the test results are tabulated in Table 1.
[0105] Table 1
[0106] Sample Porosity (%) Proportion of mesopores (%) Example 1 93.74 98.72 Comparative Example 1 80.42 60.63 Comparative Example 2 60.81 45.32 Comparative Example 3 84.77 87.62
[0107] Referring to Table 1, from the test results of Example 1 and Comparative Example 1, it can be seen that by using the preparation process of porous carbon provided in the embodiments of the present application, that is, using anhydrous metal chloride as both a hydrogen bond acceptor and a hydrogen bond donor to form a deep eutectic solvent, so that asphalt can be homogeneously dispersed in the solvent and there is a template agent that can assist in pore formation and is uniformly dispersed among the asphalt molecules in the carbonization precursor; compared with the preparation of porous carbon by the conventional templating method, that is, directly mixing asphalt, organic solvent and template agent, since the former can better assist the dispersion of asphalt in the solvent, the porous carbon material prepared by the former has the advantages of higher porosity and more uniform pore size.
[0108] From the test results of Example 1 and Comparative Example 2, it can be seen that by using the hydrogen bond acceptor provided in the embodiments of the present application (i.e., anhydrous metal chloride that can act as a template agent), compared with using a conventional hydrogen bond acceptor (i.e., choline chloride), since the former has the function of assisting in pore formation, the porous carbon material prepared by the former has the advantages of higher porosity and more uniform pore size.
[0109] From the test results of Example 1 and Comparative Example 3, it can be seen that by using anhydrous metal chloride that can act as a template agent as a hydrogen bond acceptor, compared with the form of using other hydrogen bond acceptors that cannot act as template agents and additionally adding a template agent, the former can make the template agent more uniformly distributed in the asphalt, and thus the porous carbon material prepared by the former has the advantages of higher porosity and more uniform pore size.
[0110] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.
Claims
1. A preparation method of an asphalt-based porous carbon material, characterized in that, It includes the following steps: S1 Mix a hydrogen bond donor and a hydrogen bond acceptor under heating conditions, wherein the hydrogen bond acceptor includes anhydrous metal chloride, to obtain a deep eutectic solvent; S2 Add pitch to the deep eutectic solvent and successively perform mixing treatment and drying treatment to obtain a carbonization precursor; S3 Carbonize the carbonization precursor under an inert atmosphere to obtain a porous carbon precursor; S4 Perform pickling treatment and water washing treatment on the porous carbon precursor to obtain a pitch-based porous carbon material.
2. The preparation method according to claim 1, wherein, The hydrogen bond donor includes a polyol having 2 to 5 carbon atoms, and / or the anhydrous metal chloride is selected from at least one of zinc chloride, aluminum chloride, and iron chloride.
3. The preparation method according to claim 2, wherein The polyol is selected from at least one of ethylene glycol, glycerol, 1,3-propanediol, 1,4-butanediol, pentaerythritol, and neopentyl glycol.
4. The preparation method according to claim 3, characterized in that, The molar ratio of the hydrogen bond donor to the hydrogen bond acceptor is 1:(0.1 - 5).
5. The preparation method according to any one of claims 1 to 4, characterized in that, The lowest melting point of the components in the hydrogen bond donor is M1, and the lowest melting point of the components in the hydrogen bond acceptor is M2. In the step of mixing the hydrogen bond donor and the hydrogen bond acceptor under heating conditions, the heating temperature is T, where T satisfies the relational expression:
6. The production method according to any one of claims 1 to 4, characterized in that The mass ratio of the pitch to the deep eutectic solvent is 1:(1 - 30).
7. The preparation method according to any one of claims 1 to 4, characterized in that The softening point of the pitch is 120 - 250 °C.
8. The preparation method according to any one of claims 1 to 4, characterized in that, The step of carbonizing the carbonization precursor under an inert atmosphere includes: heating the carbonization precursor under an inert atmosphere, and then maintaining the temperature constant for heat preservation carbonization treatment. In the heating treatment step, the heating rate is 3 - 5 °C / min, and / or in the heat preservation carbonization treatment step, the treatment temperature is 600 - 1000 °C, and the treatment time is 2 - 4 h.
9. The preparation method according to claim 8, characterized in that, The inert atmosphere is selected from at least one of nitrogen and argon, and / or the gas flow rate of the inert atmosphere is 20 - 50 mL / min.
10. An asphalt-based porous carbon material, characterized in that, It is prepared by using the preparation method according to any one of claims 1 - 9.