Method for preparing high specific surface area porous carbon material based on asphalt and silicon source and application thereof

Abstract

The application relates to the technical field of advanced carbon material synthesis, and particularly discloses a method for preparing high specific surface area porous carbon material based on pitch and silicon source compounding and application thereof. The method comprises the following steps: dissolving pitch, mixing the pitch with a condensate and silicate, and obtaining a hybrid precursor through a solvothermal reaction; and then performing oxidation stabilization, segmented carbonization and alkali activation treatment in sequence to obtain the porous carbon material. The condensate is prepared by the following steps: reacting cyanuric chloride with 3-aminopropyl triethoxysilane, and then co-hydrolyzing and condensing the resultant with phenyltrimethoxysilane, and the condensate contains active silicon hydroxyl groups and phenyl groups, and can effectively control the pore structure of the material. The application significantly improves the interface compatibility of pitch and inorganic silicon source, realizes the molecular-level uniform dispersion of organic and inorganic components and in-situ nitrogen doping, the prepared carbon material has ultrahigh specific surface area and developed hierarchical pore structure, and exhibits excellent electrochemical performance, and has wide application prospects in the field of energy storage device electrode materials.

Description

Technical Field

[0001] This invention relates to the field of advanced carbon material synthesis technology, and more specifically, to a method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source, and its application. Background Technology

[0002] Porous carbon materials, due to their high specific surface area, tunable pore structure, and excellent chemical stability, have shown broad application prospects in electrochemical energy storage, catalysis, and adsorption separation. Especially in energy storage devices such as lithium-ion batteries and supercapacitors, porous carbon, as an electrode material, can significantly improve the energy density and power density of devices by optimizing ion transport pathways and charge storage sites. Traditional raw materials for preparing porous carbon mainly include biomass, polymers, and pitch. Among these, pitch, due to its high carbon content, wide availability, and low cost, has become one of the important precursors for the industrial production of porous carbon.

[0003] However, in existing technologies, the performance optimization of pitch-based porous carbon materials still faces many challenges: First, the interfacial compatibility between pitch and inorganic templates or silicon sources is poor, easily leading to uneven component dispersion and making it difficult to achieve molecular-level pore structure control; second, although conventional template or activation methods can prepare carbon materials with high specific surface area, they often rely on highly corrosive activators or complex template removal processes, which are not only environmentally unfriendly but also prone to pore collapse or specific surface area loss; third, existing technologies cannot simultaneously achieve synergistic control of high specific surface area, hierarchical pore structure, and heteroatom doping, limiting the performance improvement of materials in terms of high-speed ion transport and surface reaction kinetics. Therefore, this invention provides a method for preparing high specific surface area porous carbon materials based on pitch and silicon source composites and its application, to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite and its application. It significantly improves the interfacial compatibility between asphalt and inorganic silicon source, realizes molecular-level uniform dispersion of organic and inorganic components and in-situ nitrogen doping. The prepared carbon material has ultra-high specific surface area and well-developed hierarchical pore structure, exhibits excellent electrochemical performance, and has broad application prospects in the field of electrode materials for energy storage devices.

[0005] To achieve the above objectives, the first technical solution adopted by the present invention is:

[0006] A method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source adopts the following technical solution:

[0007] S1. Disperse 22-26 parts of asphalt with a softening point of 80-130℃ in 95-100 parts of anhydrous xylene, stir at 90-135℃ for 45-55 minutes, take 8-12 parts of the concentrate, dissolve it in 15-20 parts of anhydrous xylene and add it to the mixture, stir at a constant temperature for 30-40 minutes to make it uniformly mixed, then add 6-10 parts of silicate ester and 0.6-0.9 parts of glacial acetic acid dropwise to the system and continue stirring for 10-20 minutes to obtain a mixture;

[0008] S2. The mixture obtained in step S1 is transferred to a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner and reacted at 110-150℃ for 4-8 hours. After the reaction is completed, it is cooled to room temperature, and then obtained by vacuum distillation, vacuum drying, and grinding into fine powder to obtain the hybrid precursor.

[0009] S3. Place the hybrid precursor obtained in step S2 in a tube furnace and heat it to 270-290℃ at 1-1.5℃ / min in an air atmosphere, and hold it for 4-6h for oxidation stabilization. Then switch to a nitrogen atmosphere and heat it to 650-800℃ at 3-5℃ / min and hold it for 2-3h. Then continue to heat it to 950-1050℃ at the same rate and hold it for 2-4h. After naturally cooling to room temperature, carbon composite material is obtained.

[0010] S4. Mix the carbon composite material of S3 with 45-55wt% potassium hydroxide at a solid-liquid ratio of 1g:(3-4)ml. Stir at 70-80℃ and 300-340rpm for 2-4h. After vacuum drying, place it in a tube furnace and activate it at 800-900℃ for 1-2h under argon protection at a rate of 5℃ / min. Wash the activated product with hydrochloric acid solution until neutral, then wash it repeatedly with deionized water. Finally, vacuum dry to obtain the porous carbon material.

[0011] Preferably, the preparation step of the concentrate in step S1 is as follows:

[0012] (1) Dissolve 15-25 parts of cyanuric chloride in 95-100 parts of dry tetrahydrofuran, cool to 0-5℃ in an ice-water bath, and slowly add a mixture of 20-25 parts of 3-aminopropyltriethoxysilane and 20-25 parts of triethylamine under nitrogen protection, controlling the dropping rate to keep the reaction temperature ≤10℃; after the dropping is complete, heat to 65-75℃ and reflux for 4-6 hours, then filter while hot, and obtain the silane monomer by rotary evaporation under reduced pressure.

[0013] (2) Take 25-30 parts of the silane monomer obtained from S1 and mix it with 20-25 parts of phenyltrimethoxysilane. Add 100-110 parts of anhydrous ethanol and add 8-12 parts of 0.1M hydrochloric acid aqueous solution dropwise at 210-260 rpm. Stir and react at 45-55℃ for 16-24 h to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. Remove the solvent by vacuum distillation to obtain the concentrate.

[0014] Preferably, the specific process parameters and component dosages of step S1 are as follows: 22-26 parts of asphalt are dissolved in 95-100 parts of anhydrous xylene, stirred at 90-165℃ for 45-55 minutes, the amount of concentrate added is 8-12 parts, the amount of anhydrous xylene used to dissolve the concentrate is 15-20 parts, and the stirring time at constant temperature after addition is 30-40 minutes; the amount of silicate ester added is 6-10 parts, the amount of glacial acetic acid added is 0.6-0.9 parts, and the stirring time after dropwise addition is 10-20 minutes.

[0015] Preferably, in step S1, the asphalt softening point is 80-150℃ and is selected from petroleum asphalt or coal tar pitch; the silicate ester is selected from at least one of methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate.

[0016] Preferably, the specific process conditions for step S2 are as follows: the reactor is a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner; the reaction temperature is 110-180℃ and the time is 4-8h.

[0017] Preferably, the specific process conditions for step S3 are as follows: oxidation stabilization stage: heating to 270-290℃ at 1-1.5℃ / min and holding at that temperature for 4-6h; carbonization stage: heating to 650-800℃ at 3-5℃ / min and holding at that temperature for 2-3h, then continuing to heat to 950-1050℃ at the same rate and holding at that temperature for 2-4h.

[0018] Preferably, the specific process parameters and component dosages in step S4 are as follows: the potassium hydroxide concentration is 45-55 wt%, the solid-liquid ratio of the carbon composite material to the potassium hydroxide solution is 1 g: (3-4) ml; the stirring conditions during mixing are: stirring at 70-80℃ and 300-340 rpm for 2-4 hours; the activation conditions are: activating at 800-900℃ at 5℃ / min for 1-2 hours; and the acid used for pickling is hydrochloric acid solution.

[0019] Preferably, the specific process parameters and component dosages in step (1) are as follows: 15-25 parts of cyanuric chloride are dissolved in 95-100 parts of dry tetrahydrofuran, the cooling temperature is 0-5℃, the mixture is composed of 20-25 parts of 3-aminopropyltriethoxysilane and 20-25 parts of triethylamine, the dropping rate is controlled so that the reaction temperature is ≤10℃, the reflux reaction temperature is 65-75℃, and the time is 4-6h.

[0020] Preferably, the specific process parameters and component dosages in step (2) are as follows: 25-30 parts of silane monomer and 20-25 parts of phenyltrimethoxysilane are mixed, 100-110 parts of anhydrous ethanol are added, and 8-12 parts of 0.1M hydrochloric acid aqueous solution are added dropwise at 210-260 rpm. The mixture is stirred and reacted at 45-55℃ for 16-24 h.

[0021] The second technical solution adopted in this invention is: the application of porous carbon material prepared by the above method in the electrode material of energy storage device.

[0022] In summary, the present invention has the following beneficial effects:

[0023] 1. This invention involves mixing asphalt with a concentrate prepared through a specific process and silicate ester to obtain a mixed solution. After a solvothermal reaction to obtain a hybrid precursor, the solution undergoes sequential oxidative stabilization, segmented carbonization, and alkali activation treatments, forming a complete process for preparing asphalt-based porous carbon materials. This process, through the synergistic design of sol-gel, solvothermal, oxidative carbonization, and alkali activation, effectively solves the problems of poor interfacial compatibility between asphalt and inorganic silicon sources, uneven component dispersion, difficulty in controlling pore structure, and the challenge of simultaneously achieving in-situ heteroatom doping in existing technologies. By leveraging the bridging effect of the concentrate and the orderly coordination of multiple processes, it achieves molecular-level uniform dispersion of organic and inorganic components and in-situ doping of nitrogen, significantly improving the overall electrochemical performance of porous carbon materials. Simultaneously, the pre-modification through oxidative stabilization and the gradient treatment through segmented carbonization avoids problems such as pore collapse and phase separation during high-temperature molding, ensuring the integrity and development of the hierarchical pore structure, reducing the complexity of the process operation, and demonstrating good operability and industrial application potential.

[0024] 2. The concentrate of the present invention is prepared by reflux reaction of cyanuric chloride and 3-aminopropyltriethoxysilane to obtain silane monomer, and then by co-hydrolysis and condensation with phenyltrimethoxysilane. The concentrate contains active silanol groups and phenyl functional groups, constituting a functional component that combines interfacial compatibility regulation and pore structure control. This concentrate, leveraging the reactivity of active silanol groups, the compatibility of phenyl groups, and the nitrogen element derived from cyanuric chloride, forms a multifunctional synergistic system. This system effectively improves the interfacial compatibility between pitch and inorganic silicon sources and enables in-situ heteroatom doping of carbon materials. Specifically, the active silanol groups undergo hydrolytic condensation with silicate esters to form covalent bonds, achieving molecular-level bonding between organic and inorganic phases. The phenyl functional groups further enhance the dispersion effect through their compatibility with the aromatic hydrocarbons of pitch. Nitrogen elements from the cyanuric chloride framework are directionally doped into the carbon framework during subsequent carbonization. The synergistic effect of these functional groups significantly improves the uniformity of the hybrid precursor, greatly enhancing the pore-forming efficiency during subsequent carbonization and activation processes. This ensures the effective construction of the ultra-high specific surface area and well-developed hierarchical pore structure of the porous carbon material, providing a crucial guarantee for achieving excellent electrochemical performance. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used, unless otherwise specified, were all purchased from conventional biochemical reagent stores. All quantitative experiments in the following examples were performed in triplicate, and the data are the average of the three replicates or the average ± standard deviation.

[0027] Example 1

[0028] This embodiment provides a method for preparing high specific surface area porous carbon materials based on a composite of pitch and silicon source, using the following technical solution:

[0029] Preparation of concentrate

[0030] (1) Dissolve 15 parts of cyanuric chloride in 95 parts of dry tetrahydrofuran, cool to 0°C in an ice-water bath, and slowly add a mixture of 20 parts of 3-aminopropyltriethoxysilane and 20 parts of triethylamine at a rate of 5 mL / min under nitrogen protection, controlling the dropping rate to keep the reaction temperature ≤10°C; after the dropping is complete, raise the temperature to 65°C and reflux at 300 rpm for 6 h, filter while hot after the reaction is complete, and obtain the silane monomer by rotary evaporation under reduced pressure.

[0031] (2) Take 25 parts of the above silane monomer and 20 parts of phenyltrimethoxysilane, add 100 parts of anhydrous ethanol, stir at 210 rpm and add 8 parts of 0.1M hydrochloric acid aqueous solution dropwise. After the addition is complete, stir at 210 rpm at 45°C for 24 h to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. Remove the solvent by vacuum distillation to obtain the concentrate.

[0032] Preparation of porous carbon materials

[0033] S1. Disperse 22 parts of petroleum asphalt with a softening point of 80℃ in 95 parts of anhydrous xylene, and stir at 300 rpm for 55 min at 90℃. Take 8 parts of the above concentrate, dissolve it in 15 parts of anhydrous xylene, and add it to the mixture. Stir at 300 rpm for 40 min at a constant temperature to make it uniformly mixed. Then add 6 parts of tetraethyl orthosilicate and 0.6 parts of glacial acetic acid dropwise to the system, and continue stirring at 300 rpm for 20 min to obtain a mixture.

[0034] S2. The mixture obtained in step S1 is transferred to a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner and reacted at 110°C for 8 hours. After the reaction is completed, it is cooled to room temperature, and then obtained by vacuum distillation, vacuum drying, and grinding into fine powder to obtain the hybrid precursor.

[0035] S3. The hybrid precursor obtained in step S2 is placed in a tube furnace and heated to 270°C at 1°C / min in an air atmosphere and held for 6 hours for oxidation stabilization. Then, the atmosphere is switched to nitrogen and heated to 650°C at 3°C / min and held for 3 hours. Then, the temperature is increased to 950°C at the same rate and held for 4 hours. After naturally cooling to room temperature, carbon composite material is obtained.

[0036] S4. Mix the carbon composite material from S3 with 45wt% potassium hydroxide at a solid-liquid ratio of 1g:3ml. Stir at 70℃ and 300rpm for 4h. After vacuum drying, place it in a tube furnace and activate it at 800℃ for 2h under argon protection by increasing the temperature at 5℃ / min. Wash the activated product with hydrochloric acid solution until neutral, then wash it repeatedly with deionized water. Finally, vacuum dry to obtain the porous carbon material.

[0037] Example 2

[0038] This embodiment provides a method for preparing high specific surface area porous carbon materials based on a composite of pitch and silicon source, using the following technical solution:

[0039] Preparation of concentrate

[0040] (1) Dissolve 20 parts of cyanuric chloride in 95 parts of dry tetrahydrofuran, cool it to 2°C in an ice-water bath, and slowly add a mixture of 22 parts of 3-aminopropyltriethoxysilane and 22 parts of triethylamine at a rate of 7 mL / min under nitrogen protection, controlling the dropping rate to keep the reaction temperature ≤10°C; after the dropping is complete, raise the temperature to 70°C and reflux at 320 rpm for 5 h, filter while hot after the reaction is complete, and obtain the silane monomer by rotary evaporation under reduced pressure.

[0041] (2) Take 27 parts of the above silane monomer and 22 parts of phenyltrimethoxysilane, add 105 parts of anhydrous ethanol, stir at 230 rpm and add 10 parts of 0.1M hydrochloric acid aqueous solution dropwise. After the addition is complete, stir at 230 rpm at 50°C for 20 h to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. Remove the solvent by vacuum distillation to obtain the concentrate.

[0042] Preparation of porous carbon materials

[0043] S1. Disperse 24 parts of coal tar pitch with a softening point of 110℃ in 97 parts of anhydrous xylene, and stir at 320 rpm at 120℃ for 50 min. Take 10 parts of the above concentrate, dissolve it in 17 parts of anhydrous xylene, and add it to the mixture. Stir at 320 rpm at a constant temperature for 35 min to make it uniformly mixed. Then add 8 parts of tetraethyl orthosilicate and 0.75 parts of glacial acetic acid dropwise to the system, and continue stirring at 320 rpm for 15 min to obtain a mixture.

[0044] S2. The mixture obtained in step S1 is transferred to a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner and reacted at 140°C for 6 hours. After the reaction is completed, it is cooled to room temperature and then subjected to vacuum distillation, vacuum drying, and grinding into fine powder to obtain the hybrid precursor.

[0045] S3. The hybrid precursor obtained in step S2 is placed in a tube furnace and heated to 280°C at 1.2°C / min in an air atmosphere and held for 5 hours for oxidation stabilization. Then, the atmosphere is switched to nitrogen and heated to 720°C at 4°C / min and held for 2.5 hours. Then, the temperature is increased to 1000°C at the same rate and held for 3 hours. After naturally cooling to room temperature, a carbon composite material is obtained.

[0046] S4. Mix the carbon composite material from S3 with 50wt% potassium hydroxide at a solid-liquid ratio of 1g:3.5ml. Stir at 75℃ and 320rpm for 3h. After vacuum drying, place it in a tube furnace and activate it at 850℃ for 1.5h under argon protection by increasing the temperature at 5℃ / min. Wash the activated product with hydrochloric acid solution until neutral, then wash it repeatedly with deionized water. Finally, vacuum dry to obtain the porous carbon material.

[0047] Example 3

[0048] This embodiment provides a method for preparing high specific surface area porous carbon materials based on a composite of pitch and silicon source, using the following technical solution:

[0049] Preparation of concentrate

[0050] (1) Dissolve 25 parts of cyanuric chloride in 100 parts of dry tetrahydrofuran, cool it to 5°C in an ice-water bath, and slowly add a mixture of 25 parts of 3-aminopropyltriethoxysilane and 25 parts of triethylamine at a rate of 10 mL / min under nitrogen protection, controlling the dropping rate to keep the reaction temperature ≤10°C; after the dropping is complete, raise the temperature to 75°C and reflux at 350 rpm for 4 h. After the reaction is complete, filter while hot, and obtain the silane monomer by rotary evaporation under reduced pressure.

[0051] (2) Take 30 parts of the above silane monomer and 25 parts of phenyltrimethoxysilane, add 110 parts of anhydrous ethanol, stir at 260 rpm and add 12 parts of 0.1M hydrochloric acid aqueous solution dropwise. After the addition is complete, stir at 260 rpm at 55°C for 16 h to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. Remove the solvent by vacuum distillation to obtain the concentrate.

[0052] Preparation of porous carbon materials

[0053] S1. Disperse 26 parts of petroleum asphalt with a softening point of 150℃ in 100 parts of anhydrous xylene, and stir at 165℃ and 350 rpm for 45 min. Take 12 parts of the above concentrate, dissolve it in 20 parts of anhydrous xylene, and add it to the mixture. Stir at 350 rpm for 30 min at a constant temperature to make it uniformly mixed. Then add 10 parts of propyl orthosilicate and 0.9 parts of glacial acetic acid dropwise to the system, and continue stirring at 350 rpm for 10 min to obtain a mixture.

[0054] S2. The mixture obtained in step S1 is transferred to a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner and reacted at 180°C for 4 hours. After the reaction is completed, it is cooled to room temperature, and then obtained by vacuum distillation, vacuum drying, and grinding into fine powder to obtain the hybrid precursor.

[0055] S3. The hybrid precursor obtained in step S2 is placed in a tube furnace and heated to 290°C at 1.5°C / min in an air atmosphere and held for 4 hours for oxidation stabilization. Then, the atmosphere is switched to nitrogen and heated to 800°C at 5°C / min and held for 2 hours. Then, the temperature is increased to 1050°C at the same rate and held for 2 hours. After naturally cooling to room temperature, carbon composite material is obtained.

[0056] S4. Mix the carbon composite material from S3 with 55wt% potassium hydroxide at a solid-liquid ratio of 1g:4ml. Stir at 80℃ and 340rpm for 2h. After vacuum drying, place it in a tube furnace and activate it at 900℃ for 1h under argon protection by increasing the temperature at 5℃ / min. Wash the activated product with hydrochloric acid solution until neutral, then wash it repeatedly with deionized water. Finally, vacuum dry to obtain the porous carbon material.

[0057] Example 4

[0058] This embodiment provides a method for preparing high specific surface area porous carbon materials based on a composite of pitch and silicon source, using the following technical solution:

[0059] Preparation of concentrate

[0060] (1) Dissolve 22 parts of cyanuric chloride in 98 parts of dry tetrahydrofuran, cool in an ice-water bath to 3°C, and slowly add a mixture of 23 parts of 3-aminopropyltriethoxysilane and 23 parts of triethylamine at a rate of 8 mL / min under nitrogen protection, controlling the dropping rate to keep the reaction temperature ≤10°C; after the dropping is complete, raise the temperature to 72°C and reflux at 340 rpm for 4.5 h, filter while hot after the reaction is complete, and obtain the silane monomer by rotary evaporation under reduced pressure.

[0061] (2) Take 28 parts of the above silane monomer and 24 parts of phenyltrimethoxysilane, add 108 parts of anhydrous ethanol, stir at 250 rpm and add 11 parts of 0.1M hydrochloric acid aqueous solution dropwise. After the addition is complete, stir at 52℃ and 250 rpm for 18 h to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. Remove the solvent by vacuum distillation to obtain the concentrate.

[0062] Preparation of porous carbon materials

[0063] S1. Disperse 25 parts of coal tar pitch with a softening point of 120℃ in 98 parts of anhydrous xylene, and stir at 140℃ and 340 rpm for 48 min. Take 11 parts of the above concentrate, dissolve it in 18 parts of anhydrous xylene, and add it to the mixture. Stir at 340 rpm for 32 min at a constant temperature to make it uniformly mixed. Then add 9 parts of tetraethyl orthosilicate and 0.8 parts of glacial acetic acid dropwise to the system and continue stirring at 340 rpm for 12 min to obtain a mixture.

[0064] S2. The mixture obtained in step S1 is transferred to a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner and reacted at 160°C for 5 hours. After the reaction is completed, it is cooled to room temperature, and then subjected to vacuum distillation, vacuum drying, and grinding into fine powder to obtain the hybrid precursor.

[0065] S3. The hybrid precursor obtained in step S2 is placed in a tube furnace and heated to 285°C at 1.3°C / min in air atmosphere and held for 4.5h for oxidation stabilization. Then, the atmosphere is switched to nitrogen atmosphere and heated to 780°C at 4.5°C / min and held for 2.2h. Then, the temperature is increased to 1020°C at the same rate and held for 2.5h. After naturally cooling to room temperature, carbon composite material is obtained.

[0066] S4. Mix the carbon composite material from S3 with 52wt% potassium hydroxide at a solid-liquid ratio of 1g:3.8ml. Stir at 78℃ and 330rpm for 2.5h. After vacuum drying, place it in a tube furnace and activate it at 880℃ for 1.3h under argon protection by increasing the temperature at 5℃ / min. Wash the activated product with hydrochloric acid solution until neutral, then wash it repeatedly with deionized water. Finally, vacuum dry to obtain the porous carbon material.

[0067] Comparative Example 1

[0068] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that no concentrate is added. That is, no concentrate is added in step S1, and no concentrate dissolution operation is performed. After the asphalt is dispersed, tetraethyl orthosilicate and glacial acetic acid are added dropwise. Other conditions are the same as in Example 4.

[0069] Comparative Example 2

[0070] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that phenyltrimethoxysilane is not added in the preparation of the concentrate. That is, the addition of phenyltrimethoxysilane is omitted in the concentrate preparation step (2). The concentrate is prepared by reacting silane monomer with anhydrous ethanol and hydrochloric acid aqueous solution. Other conditions are the same as in Example 4.

[0071] Comparative Example 3

[0072] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that the nitrogen-containing triazine ring structure is not introduced in the preparation process of the concentrate, that is, the concentrate preparation step (1) is omitted, and 3-aminopropyltriethoxysilane and phenyltrimethoxysilane are directly mixed to carry out the hydrolysis and condensation reaction in step (2), and other conditions are the same as in Example 4.

[0073] Comparative Example 4

[0074] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that it does not use a special concentrate, but uses commercially available silane coupling agent KH-550 instead. That is, in step S1, the concentrate is replaced with an equal amount of KH-550, and other conditions are the same as in Example 4.

[0075] Comparative Example 5

[0076] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that an inorganic silicon source precursor is not added, that is, the dropwise addition steps of tetraethyl orthosilicate and glacial acetic acid are omitted in step S1, and only the concentrate is used as a single silicon source. Other conditions are the same as in Example 4.

[0077] Comparative Example 6

[0078] A method for preparing high specific surface area porous carbon materials based on asphalt and silicon source composite is different from Example 4 in that the alkaline chemical activation treatment is not performed, that is, step S4 is omitted. The carbon composite material prepared in step S3 is directly acid-washed to remove the inorganic silicon component and then washed and dried. Other conditions are the same as in Example 4.

[0079] Performance testing

[0080] The asphalt and silica-based compounds prepared in Examples 1-4 and Comparative Examples 1-6 above

[0081] The performance of high specific surface area porous carbon materials prepared by source composite was observed, and the test results are shown in Table 1:

[0082] Table 1

[0083] Example 1 2015 0.44 41.9 276 95.9 Example 2 2348 0.52 42.9 305 96.8 Example 3 2652 0.60 43.5 332 97.5 Example 4 2865 0.67 44.1 358 98.2 Comparative Example 1 628 0.25 28.0 85 68.2 Comparative Example 2 1152 0.55 36.4 158 81.6 Comparative Example 3 1385 0.68 39.7 186 85.3 Comparative Example 4 864 0.38 31.6 122 75.8 Comparative Example 5 1623 0.33 40.7 215 88.7 Comparative Example 6 1856 0.37 40.2 242 91.5

[0084] As can be seen from the table data, the pitch-based porous carbon materials prepared in Examples 1-4 of this invention exhibit excellent structural and electrochemical properties, fully demonstrating the precise control effect of the core process of this invention on the pore structure of the material. The well-developed and reasonable hierarchical pore structure provides a smooth path for ion transport and increases the effective sites for charge storage, which not only improves the specific capacitance of the material but also enhances the structural stability during cycling. Among them, Example 4, as the product of the optimal combination of process parameters, has the most fully developed pore structure, and all structural and electrochemical performance indicators are the best among the examples.

[0085] In contrast, the comparative examples exhibited shortcomings in various dimensions due to the absence or substitution of key steps in material preparation. Comparative Example 1, lacking the core concentrate component entirely, suffered from severely underdeveloped structure, resulting in lagging performance across all indicators. Data from Comparative Examples 2, 3, and 4 demonstrate that the phenyl structure, nitrogen doping source, and unique molecular configuration in the specially formulated concentrate are crucial for forming an ideal mesoporous network and enhancing electrochemical activity; using incomplete formulations or ordinary commercial coupling agents cannot achieve the same effect. Data from Comparative Examples 5 and 6 further reveal the importance of process integrity. Although they may resemble some examples in terms of individual structural parameters, the absence of the synergistic pore-forming effect of the inorganic silicon source or the crucial alkaline activation pore-expansion step results in significant differences in their final electrochemical performance, particularly the specific capacitance reflecting rapid charge-discharge capability, compared to the examples with complete processes.

[0086] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source, characterized in that, Includes the following steps: S1. Disperse asphalt in anhydrous xylene, stir, add concentrate dissolved in anhydrous xylene, stir at constant temperature to make it uniformly mixed, then add silicate ester and glacial acetic acid dropwise to the system and continue stirring to obtain a mixture. S2. Transfer the mixture obtained in step S1 to a reaction vessel and carry out a high-temperature and high-pressure reaction. After the reaction is completed, cool to room temperature, and obtain the hybrid precursor by vacuum distillation, vacuum drying, and grinding into fine powder. S3. The hybrid precursor obtained in step S2 is placed in a tube furnace and heated and held in an air atmosphere to complete the oxidation stabilization. Then, the atmosphere is switched to nitrogen, and the temperature is continued to rise and segmented isothermal carbonization is carried out. After naturally cooling to room temperature, carbon composite material is obtained. S4. The carbon composite material obtained in step S3 is mixed with potassium hydroxide in a certain proportion and reacted under stirring. After vacuum drying, it is placed in a tube furnace, heated and activated under argon protection. The activated product is acid washed until neutral, then repeatedly washed with deionized water, and finally vacuum dried to obtain porous carbon material.

2. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, The concentrate in step S1 is prepared by the following steps: (1) Dissolve cyanuric chloride in dry tetrahydrofuran, and add a mixture of 3-aminopropyltriethoxysilane and triethylamine dropwise under ice-water bath cooling and nitrogen protection. After the addition is complete, heat up and reflux the reaction, filter while hot, and obtain silane monomer by rotary evaporation under reduced pressure. (2) The silane monomer is mixed with phenyltrimethoxysilane, anhydrous ethanol is added, and hydrochloric acid aqueous solution is added dropwise. The reaction is carried out under stirring to obtain a phenyl-modified siloxane oligomer solution containing active silanol groups. The solvent is removed by vacuum distillation to obtain the concentrate.

3. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, The specific process parameters and component dosages for step S1 are as follows: 22-26 parts of asphalt are dissolved in 95-100 parts of anhydrous xylene, and stirred at 90-165℃ for 45-55 minutes. The amount of concentrate added is 8-12 parts, and the amount of anhydrous xylene used to dissolve the concentrate is 15-20 parts. The stirring time after addition is 30-40 minutes. The amount of silicate ester added is 6-10 parts, and the amount of glacial acetic acid added is 0.6-0.9 parts. The stirring time after dropwise addition is 10-20 minutes.

4. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, In step S1, the asphalt softening point is 80-150℃ and is selected from petroleum asphalt or coal tar pitch; the silicate ester is selected from at least one of methyl orthosilicate, ethyl orthosilicate and propyl orthosilicate.

5. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, The specific process conditions for step S2 are as follows: the reactor is a high-temperature and high-pressure reactor with a polytetrafluoroethylene liner; the reaction temperature is 110-180℃ and the time is 4-8h.

6. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, The specific process conditions for step S3 are as follows: Oxidation stabilization stage: heat up to 270-290℃ at 1-1.5℃ / min and hold for 4-6h; Carbonization stage: heat up to 650-800℃ at 3-5℃ / min and hold for 2-3h, then continue to heat up to 950-1050℃ at the same rate and hold for 2-4h.

7. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 1, characterized in that, The specific process parameters and component dosages in step S4 are as follows: the potassium hydroxide concentration is 45-55 wt%, the solid-liquid ratio of the carbon composite material to the potassium hydroxide solution is 1 g: (3-4) ml; the stirring conditions during mixing are: stirring at 70-80℃ and 300-340 rpm for 2-4 hours; the activation conditions are: activating at 800-900℃ at 5℃ / min for 1-2 hours; the acid used for pickling is hydrochloric acid solution.

8. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 2, characterized in that, The specific process parameters and component dosages in step (1) are as follows: 15-25 parts of cyanuric chloride are dissolved in 95-100 parts of dry tetrahydrofuran, the cooling temperature is 0-5℃, the mixture is composed of 20-25 parts of 3-aminopropyltriethoxysilane and 20-25 parts of triethylamine, the dropping rate is controlled so that the reaction temperature is ≤10℃, the reflux reaction temperature is 65-75℃, and the time is 4-6h.

9. The method for preparing high specific surface area porous carbon materials based on the composite of pitch and silicon source according to claim 2, characterized in that, The specific process parameters and component dosages in step (2) are as follows: Take 25-30 parts of silane monomer and 20-25 parts of phenyltrimethoxysilane, add 100-110 parts of anhydrous ethanol, add 8-12 parts of 0.1M hydrochloric acid aqueous solution dropwise at 210-260 rpm, and stir the reaction at 45-55℃ for 16-24 h.

10. The application of a porous carbon material prepared by the method according to any one of claims 1-9 in an electrode material for an energy storage device.