Preparation method of controllable porous carbon based on super-crosslinked resin, porous carbon and application
By controlling the degree of crosslinking of the hypercrosslinked resin and the carbonization temperature and time, a single-step carbonization reaction of porous carbon was achieved, solving the problems of complexity and high cost of existing porous carbon preparation methods, and making it suitable for large-scale industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIYANG TIANMU PILOT BATTERY MATERIAL TECH CO LTD
- Filing Date
- 2024-11-04
- Publication Date
- 2026-05-08
Smart Images
Figure CN121990548A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of porous carbon preparation technology, and in particular to a method for preparing tunable porous carbon based on hypercrosslinked resin, porous carbon, and its applications. Background Technology
[0002] Porous carbon is a class of carbon materials with highly developed pore structures, encompassing types such as activated carbon, carbon molecular sieves, carbon fibers, and carbon aerogels. Based on pore size, porous carbon can be classified into micropores (<2nm), mesopores (2-50nm), and macropores (>50nm). Due to its excellent electrical conductivity, high specific surface area, low density, and chemical stability, porous carbon shows broad application prospects in energy storage and conversion (such as supercapacitors and lithium-ion batteries), environmental remediation, petrochemicals, and biomedicine.
[0003] Currently, the preparation of porous carbon mainly relies on template methods and activation methods. Activation methods include chemical activation and physical activation. Chemical activation uses activators such as KOH, H3PO4, and ZnCl2 to obtain porous structures with well-developed pores, but its preparation process requires sophisticated equipment and strict control over pollutant emissions. Physical activation uses CO2 or steam, but it also requires high-quality equipment and precursors. Template methods are further divided into hard template methods and soft template methods. Hard template methods can achieve uniform pore structures, but the template removal process is complex and costly; soft template methods control the material structure through intermolecular forces, and although the process is simpler, the reagent cost is high, making industrial application difficult. Therefore, developing a one-step method for preparing porous carbon materials is imperative.
[0004] In recent years, a top-down synthesis strategy has gradually emerged, achieving precise control over pore structure through precursor structural design. For example, metal-organic frameworks (MOFs), due to their ordered pore structure, can be directly converted into porous carbon materials through high-temperature pyrolysis. However, the complex synthesis process and high cost of MOFs limit their large-scale application. Another research direction is the co-carbonization of precursor composites, such as combining phenolic resin with arylboronic acid, using arylboronic acid as a pore-forming agent. However, this method still requires acid or alkali washing to remove residual templates or inorganic salts, increasing process complexity and cost. Summary of the Invention
[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing tunable porous carbon based on hypercrosslinked resins, as well as porous carbon and its applications. This method, based on the controllability of the crosslinking degree of the hypercrosslinked resin precursor and the temperature and time of the carbonization reaction, allows for the controllable design of the pore structure of porous carbon through a single-step carbonization reaction.
[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing tunable porous carbon based on hypercrosslinked resin, comprising:
[0007] Using low-crosslinked polystyrene resin with a crosslinking degree of 1-2% as raw material, a polymerization reaction was carried out in a chloroalkane solvent system under the action of Lewis acid catalyst to prepare a hypercrosslinked resin precursor.
[0008] The supercrosslinked resin precursor was washed and dried to constant weight to obtain the impurity-removed supercrosslinked resin precursor.
[0009] The purified supercrosslinked resin precursor was placed in an inert atmosphere for carbonization treatment, and after the carbonization treatment was completed, it was cooled to room temperature to obtain a porous carbon material.
[0010] The pore structure of the porous carbon material is controlled by adjusting the degree of crosslinking of the hypercrosslinked resin precursor and the temperature and time of the carbonization treatment; the degree of crosslinking of the hypercrosslinked resin precursor is controlled by the specific type of Lewis acid catalyst, the temperature of the polymerization reaction, and the amount of chloroalkane solvent corresponding to the unit mass of low-crosslinked polystyrene resin.
[0011] Preferably, the low crosslinking polystyrene resin with a crosslinking degree of 1-2% specifically means that the crosslinking agent divinylbenzene added during the preparation of polystyrene resin accounts for 1-2% of the monomer mass.
[0012] Preferably, the Lewis acid catalyst includes one or more of ZnCl2, FeCl3, and AlCl3;
[0013] The polymerization reaction is carried out at a temperature of 25–80°C for a duration of 6–48 hours.
[0014] The chloroalkane solvent includes one or more of dichloromethane, dichloroethane, dichloropropane, or 1,2-dichloroethane.
[0015] Preferably, the amount of chloroalkane solvent added per gram of the low crosslinked polystyrene resin is 5 to 15 ml;
[0016] The mass ratio of the low crosslinked polystyrene resin to the Lewis acid catalyst is 2:0.5 to 2:1.5.
[0017] Preferably, the solvent used for washing includes ethanol;
[0018] The drying temperature is 100-120℃, and the time is 2-6 hours.
[0019] Preferably, the inert atmosphere includes a nitrogen atmosphere or an argon atmosphere;
[0020] The carbonization process specifically includes: heating to 600–1000°C at a heating rate of 2–10°C / min, and holding at that temperature for 1–5 hours.
[0021] Secondly, embodiments of the present invention provide a porous carbon material prepared by the tunable porous carbon preparation method based on hypercrosslinked resin described in the first aspect above.
[0022] Thirdly, embodiments of the present invention provide a negative electrode material, including the porous carbon material described in the second aspect above.
[0023] Fourthly, embodiments of the present invention provide a conductive additive, comprising the porous carbon material described in the second aspect above.
[0024] Fifthly, embodiments of the present invention provide a secondary battery comprising the porous carbon material described in the second aspect above.
[0025] The present invention provides a method for preparing tunable porous carbon based on hypercrosslinked resin. By controlling the degree of crosslinking of the hypercrosslinked resin precursor and the temperature and time of the carbonization reaction, the pore structure of porous carbon can be controlled through a single-step carbonization reaction. This method does not rely on activators or template removal processes, significantly simplifying the preparation process, reducing production costs, and making it suitable for large-scale industrial production. Attached Figure Description
[0026] Figure 1 A flowchart illustrating a method for preparing tunable porous carbon based on hypercrosslinked resin, provided in an embodiment of the present invention.
[0027] Figure 2 This is a schematic diagram illustrating the reaction principle and process for preparing tunable porous carbon based on hypercrosslinked resin, provided in an embodiment of the present invention.
[0028] Figure 3 This is a scanning electron microscope image of the hypercrosslinked resin precursor prepared in Example 1 of the present invention;
[0029] Figure 4 This is a scanning electron microscope image of the porous carbon material prepared in Example 2 of the present invention. Detailed Implementation
[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0031] This invention provides a method for preparing tunable porous carbon based on hypercrosslinked resin. This method prepares porous carbon materials based on hypercrosslinked resin. By controlling the degree of crosslinking and carbonization conditions of the hypercrosslinked resin precursor, a single-step carbonization process can be achieved to prepare porous carbon, and the pore structure can be designed controllably.
[0032] Figure 1 This is a flowchart illustrating a method for preparing tunable porous carbon based on hypercrosslinked resin, as provided in an embodiment of the present invention. Figure 2 A schematic diagram illustrating the reaction principle and process for preparing tunable porous carbon based on hypercrosslinked resin, provided for embodiments of the present invention. The following is in conjunction with... Figure 1 and Figure 2 The technical solution of the present invention will be described below.
[0033] The preparation method proposed in this invention mainly includes the following steps:
[0034] Step 110: Using low-crosslinked polystyrene resin with a crosslinking degree of 1-2% as raw material, a polymerization reaction is carried out in a chloroalkane solvent system under the action of Lewis acid catalyst to prepare a hypercrosslinked resin precursor.
[0035] Low crosslinked polystyrene resin with a crosslinking degree of 1-2% is specifically defined as follows: during the preparation of polystyrene resin, the crosslinking agent divinylbenzene (DVB) is added at a mass of 1-2% of the monomer. The resulting polystyrene resin is denoted as low crosslinked polystyrene resin (crosslinking degree 1-2% DVB).
[0036] Lewis acid catalysts include one or more of ZnCl2, FeCl3, and AlCl3; chloroalkane solvents include one or more of dichloromethane, dichloroethane, dichloropropane, or 1,2-dichloroethane.
[0037] The mass ratio of low crosslinked polystyrene resin to the Lewis acid catalyst is 2:0.5-2:1.5, and the amount of chloroalkane solvent added per gram of low crosslinked polystyrene resin is 5-15 ml.
[0038] The polymerization reaction temperature is 25–80℃, and the polymerization reaction time is 6–48 h.
[0039] The polymerization reaction in this step is a Friedel-Crafts alkylation reaction, the purpose of which is to introduce new bridging structures between polystyrene chains, thereby further increasing the crosslinking density and forming a hypercrosslinked polymer (HCP).
[0040] To better understand the reaction principle, we will take AlCl3 as the Lewis acid catalyst and dichloromethane as the chloroalkane solvent as an example for further explanation.
[0041] Dichloromethane is activated by the Lewis acid AlCl3 to generate a chloromethyl cation (which is positively charged), which acts as an alkylating agent.
[0042] CH2Cl2 + AlCl3 → CH2Cl + +A l C l4- .
[0043] The benzene ring in the polystyrene chain has abundant π electrons, which can act as a nucleophile to react with the generated chloromethyl cation (CH2Cl). + The reaction introduces a chloromethyl cation into the benzene ring, forming a bridged methyl link. At this point, CH₂Cl... + It undergoes an electrophilic substitution reaction with one carbon atom of the aromatic ring, forming a new C-C bond. During this process, the benzene ring temporarily loses its aromaticity, and the π-electron cloud of the benzene ring rearranges to produce a positively charged carbon atom, thus forming a carbocation intermediate. This intermediate is structurally unstable, and the carbocation intermediate will release a proton (H+). + This process allows for the reformation of a stable π-electron system. At this point, the aromatic ring regains its original electronic conjugation structure, regains its aromaticity, and ultimately yields an alkyl-substituted aromatic compound.
[0044] The reaction process described above can be simplified as follows:
[0045] Aromatic ring + R'-Cl + AlCl3 → alkylated aromatic ring + HCl.
[0046] In the above reaction process, R' is an alkyl group, corresponding to the chloroalkane solvent used.
[0047] To avoid confusion, let me clarify here. Figure 2 R in the figure represents the -CH2 group of styrene itself.
[0048] Through Friedel-Crafts alkylation, additional bridges are formed between polystyrene chains, which increases the overall crosslinking degree of the structure and enables the material to form a hypercrosslinked structure.
[0049] In this step, adjusting the type of Lewis acid catalyst, the polymerization temperature, and the amount of chloroalkane solvent can control the degree of crosslinking of the hypercrosslinked resin precursor. This is because the degree of crosslinking of the hypercrosslinked resin is directly related to the number of bridging structures formed in the crosslinking reaction. The type of Lewis acid catalyst, reaction temperature, and solvent amount all affect the manner and rate of the crosslinking reaction, thereby changing the crosslinking density of the final material. Differences in the activity of different Lewis acid catalysts lead to different efficiencies in the formation of crosslinking points; temperature changes affect the activation energy of the crosslinking reaction; and solvent amount affects the molecular diffusion rate in the solvent environment, thus affecting the uniformity and density of crosslinking.
[0050] Step 120: Wash the hypercrosslinked resin precursor and dry it to constant weight to obtain the impurity-removed hypercrosslinked resin precursor.
[0051] Specifically, the solvent used for washing includes ethanol. Washing removes unreacted monomers and impurities.
[0052] The drying temperature is 100-120℃, and the time is 2-6 hours.
[0053] Step 130: The impurity-removed supercrosslinked resin precursor is placed in an inert atmosphere for carbonization treatment, and after the carbonization treatment is completed, it is cooled to room temperature to obtain porous carbon material.
[0054] Specifically, inert atmospheres include nitrogen atmospheres or argon atmospheres.
[0055] The carbonization process specifically includes heating to 600–1000℃ at a heating rate of 2–10℃ / min and holding at that temperature for 1–5 hours.
[0056] Since carbonization temperature directly affects the degree of decomposition and rearrangement of the precursor, it can influence the pore structure. At lower temperatures (e.g., 600-800℃), more microporous structures are retained because less volatile component in the precursor volatilizes at lower temperatures, resulting in the formation of more small-diameter micropores. At higher temperatures (e.g., 800-1000℃), some micropores collapse or recombine into mesoporous or even macroporous structures, while the specific surface area decreases. However, the graphitization degree of the pore walls increases at high temperatures, making the material more conductive.
[0057] Carbonization time also affects pore structure, but this effect is more pronounced at higher temperatures. Shorter carbonization times retain more micropores, while longer carbonization processes lead to the volatilization or rearrangement of more organic matter, resulting in more mesopores and macropores. However, excessively long carbonization times may cause some micropores to collapse or close, thus affecting the specific surface area. Therefore, the carbonization time in this scheme is set at 1-5 hours.
[0058] Therefore, the tunable porous carbon preparation method based on hypercrosslinked resin provided in this invention achieves controllable design of the pore structure of porous carbon through a single-step carbonization reaction by controlling the degree of crosslinking of the hypercrosslinked resin precursor and the temperature and time of the carbonization reaction. This method does not rely on activators or template removal processes, significantly simplifies the preparation process, is highly efficient and environmentally friendly, can reduce production costs, and is suitable for large-scale industrial production.
[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0060] The low-crosslinked polystyrene resin (crosslinking degree 1-2% DVB), Lewis acid catalyst, chlorinated alkane solvent, and ethanol used for washing in the embodiments of this invention are all commercially available materials. Of course, the low-crosslinked polystyrene resin (crosslinking degree 1-2% DVB) used can also be prepared and synthesized by means commonly used in the art.
[0061] Example 1
[0062] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was complete, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-1. Scanning electron microscope image is shown below. Figure 3 As shown.
[0063] The hypercrosslinked resin HCP-1 was dried at 100℃ for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800℃ at a heating rate of 2℃ / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-1C. Scanning electron microscope images are shown below. Figure 4 As shown.
[0064] The pore structure parameters of HCP-1C were tested, and the specific surface area, pore size, and pore volume are shown in Table 1. Specific surface area was measured using the nitrogen adsorption method (BET method), pore size was measured using the Barrett-Joyner-Halinda (BJH) method based on adsorption / desorption isotherms, and pore volume was measured using the nitrogen adsorption method. These testing methods are all commonly used techniques in this field and will not be described in detail here.
[0065] Example 2
[0066] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 200 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-2.
[0067] The hypercrosslinked resin HCP-2 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-2C.
[0068] The pore structure parameters of HCP-2C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0069] Example 3
[0070] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 250 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-3.
[0071] The hypercrosslinked resin HCP-3 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-3C.
[0072] The pore structure parameters of HCP-3C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0073] Example 4
[0074] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 300 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-4.
[0075] The hypercrosslinked resin HCP-4 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-4C.
[0076] The pore structure parameters of HCP-4C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0077] Example 5
[0078] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of ZnCl2 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-5.
[0079] The hypercrosslinked resin HCP-5 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-5C.
[0080] The pore structure parameters of HCP-5C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0081] Example 6
[0082] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of FeCl3 was added and the mixture was reacted at 40 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-6.
[0083] The hypercrosslinked resin HCP-6 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-6C.
[0084] The pore structure parameters of HCP-6C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0085] Example 7
[0086] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 25 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-7.
[0087] The hypercrosslinked resin HCP-7 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-7C.
[0088] The pore structure parameters of HCP-7C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0089] Example 8
[0090] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (1% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 10 g of AlCl3 was added and the mixture was reacted at 60 °C for 24 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-8.
[0091] The hypercrosslinked resin HCP-8 was dried at 100°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 800°C at a heating rate of 2°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-8C.
[0092] The pore structure parameters of HCP-8C were tested, and the measured specific surface area, pore diameter, and pore volume are shown in Table 1.
[0093] Example 9
[0094] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (2% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 20 g of AlCl3 was added and the mixture was reacted at 80 °C for 6 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-9.
[0095] The hypercrosslinked resin HCP-9 was dried at 120°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 1000°C at a heating rate of 5°C / min and held at that temperature for 2 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-9C.
[0096] Example 10
[0097] Under a nitrogen atmosphere, 20 g of low-crosslinked polystyrene resin (2% DVB crosslinking degree) was added to 100 mL of dichloromethane solvent and stirred for 6 h until fully swollen. Then, 30 g of AlCl3 was added and the mixture was reacted at 30 °C for 36 h. After the reaction was completed, the reaction solution was filtered, washed several times with ethanol, and the sample was transferred to a vacuum drying oven for drying to obtain the hypercrosslinked resin HCP-10.
[0098] The hypercrosslinked resin HCP-10 was dried at 120°C for 3 hours and then transferred to a ceramic boat for carbonization in a tube furnace. Under a nitrogen atmosphere, it was heated to 600°C at a heating rate of 3°C / min and held at that temperature for 4 hours. After cooling to room temperature, it was washed with deionized water and dried to obtain the porous carbon material HCP-10C.
[0099] Table 1 shows the test results of pore structure parameters:
[0100]
[0101] Table 1 shows that, with constant catalyst and reaction temperature, the specific surface area of HCP-C gradually increases with increasing solvent content. This is because the solvent also acts as a crosslinking agent; increasing solvent content accelerates the crosslinking reaction and increases the polymer's specific surface area. However, when the solvent content increases to 300 mL, the specific surface area decreases slightly, possibly because excessive crosslinking agent clogs the polymer pores, reducing the crosslinking reaction rate and leading to a decrease in the specific surface area after carbonization. Furthermore, increasing the polymer reaction temperature is beneficial for increasing the specific surface area of the material after carbonization, as this is attributed to the increased temperature promoting the crosslinking reaction. With constant reaction temperature and solvent content, the specific surface area of the carbonized material obtained using AlCl3 as a catalyst is higher than that obtained using the other two catalysts, which is attributed to the difference in the promoting effect of different catalyst activities on the polymer crosslinking reaction.
[0102] The above results indicate that the tunable porous carbon preparation method based on hypercrosslinked resin proposed in this invention, by controlling the degree of crosslinking of the hypercrosslinked resin precursor and the temperature and time of the carbonization reaction, can simultaneously achieve the control of the pore structure of porous carbon materials and efficient preparation through a single-step carbonization reaction process, thereby controlling the degree of crosslinking of the precursor and the carbonization conditions. This method is suitable for large-scale industrial production.
[0103] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing tunable porous carbon based on hypercrosslinked resin, characterized in that, The preparation method includes: Using low-crosslinked polystyrene resin with a crosslinking degree of 1-2% as raw material, a polymerization reaction was carried out in a chloroalkane solvent system under the action of Lewis acid catalyst to prepare a hypercrosslinked resin precursor. The supercrosslinked resin precursor was washed and dried to constant weight to obtain the impurity-removed supercrosslinked resin precursor. The purified supercrosslinked resin precursor was placed in an inert atmosphere for carbonization treatment, and after the carbonization treatment was completed, it was cooled to room temperature to obtain a porous carbon material. The pore structure of the porous carbon material is controlled by adjusting the degree of crosslinking of the hypercrosslinked resin precursor and the temperature and time of the carbonization treatment; the degree of crosslinking of the hypercrosslinked resin precursor is controlled by the specific type of Lewis acid catalyst, the temperature of the polymerization reaction, and the amount of chloroalkane solvent corresponding to the unit mass of low-crosslinked polystyrene resin.
2. The preparation method according to claim 1, characterized in that, The low crosslinking polystyrene resin with a crosslinking degree of 1-2% specifically refers to the following: during the preparation of polystyrene resin, the crosslinking agent divinylbenzene is added, accounting for 1-2% of the monomer mass.
3. The preparation method according to claim 1, characterized in that, The Lewis acid catalyst includes one or more of ZnCl2, FeCl3, and AlCl3; The polymerization reaction is carried out at a temperature of 25–80°C for a duration of 6–48 hours. The chloroalkane solvent includes one or more of dichloromethane, dichloroethane, dichloropropane, or 1,2-dichloroethane.
4. The preparation method according to claim 1, characterized in that, The amount of chlorinated alkane solvent added per gram of the low crosslinked polystyrene resin is 5-15 ml; The mass ratio of the low crosslinked polystyrene resin to the Lewis acid catalyst is 2:0.5 to 2:1.
5.
5. The preparation method according to claim 1, characterized in that, The solvent used for washing includes ethanol; The drying temperature is 100-120℃, and the time is 2-6 hours.
6. The preparation method according to claim 1, characterized in that, The inert atmosphere includes a nitrogen atmosphere or an argon atmosphere; The carbonization process specifically includes: heating to 600–1000°C at a heating rate of 2–10°C / min, and holding at that temperature for 1–5 hours.
7. A porous carbon material prepared by a method for preparing tunable porous carbon based on a hypercrosslinked resin as described in any one of claims 1-6.
8. A negative electrode material, characterized in that, The negative electrode material includes the porous carbon material described in claim 7.
9. A conductive additive, characterized in that, The conductive additive includes the porous carbon material described in claim 7.
10. A secondary battery, characterized in that, The secondary battery comprises the porous carbon material described in claim 7.