Preparation method and application of sulfonated polybenzimidazole / benzimidazolyl covalent organic framework composite alkaline ion solvated membrane

Abstract

The invention discloses a preparation method and application of a sulfonated polybenzimidazole / benzimidazolyl covalent organic framework composite alkaline ion solvated membrane, and belongs to the technical field of energy conversion. Sulfonated polybenzimidazole is used as a polymer matrix, a benzimidazolyl covalent organic framework is synthesized in situ through a thermally induced solvent evaporation method, and the sulfonated polybenzimidazole / benzimidazolyl covalent organic framework composite alkaline ion solvated membrane is prepared. And preparing the composite alkaline ion solvated membrane taking a benzimidazole structural unit as a main body. Sulfonic acid groups on a polymer matrix can interact with amino groups, a long-range regular and ordered sub-nano-scale pore channel is realized through mediation positioning, and meanwhile, the hydroxyl conductivity of the composite ion solvated membrane can be improved through enrichment of benzimidazole functional groups. Meanwhile, the benzimidazolyl covalent organic framework filler is generated in situ in the membrane, so that the benzimidazolyl covalent organic framework filler has good compatibility and uniformity with a polybenzimidazole matrix, the mechanical property of the membrane is enhanced, and the benzimidazolyl covalent organic framework filler has a relatively good application prospect in the energy conversion fields of alkaline electrolyzed water, zinc-air batteries, carbon dioxide electroreduction, ammonia fuel cells and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of energy conversion, and in particular relates to a preparation method and application of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. Background Art

[0002] Green hydrogen production technology includes the use of wind power, hydropower, solar energy and other renewable resources to produce hydrogen by electrolysis of water, solar photolysis of water and biomass. Among them, the use of renewable energy to produce hydrogen by electrolysis of water is the most widely used and most mature method. At present, there are many technical routes for the production of hydrogen by electrolysis of water, including: alkaline water electrolysis technology (ALK), proton exchange membrane water electrolysis technology (PEM), anion exchange membrane water electrolysis technology (AEM), and solid oxide water electrolysis technology (SOEC). Among them, the acidic conditions of the proton exchange membrane electrolyzer have high requirements for the electrolyzer devices and catalysts, and the overall cost is expensive. The solid oxide water electrolysis conditions are harsh and the operating temperature is high. Both are not easy to achieve large-scale commercialization. The anion exchange membrane electrolyzer uses anion exchange membrane as an electrolyte, which combines the low cost of ALK with the simplicity and high efficiency of the PEM electrolyzer. It is currently the most advanced water electrolysis technology. However, as one of the core components of the electrolyzer, the performance of the anion exchange membrane material directly affects the output performance of the electrolyzer. Although AEM has made great progress in ionic conductivity in recent years, its alkali resistance and stability are still unsatisfactory.

[0003] Alkaline ion solvation membrane materials combine the advantages of traditional diaphragms and anion exchange membranes, and alkali is added during polymerization to form an electrolyte / water / polymer ternary homogeneous system. The polymer main chain does not contain easily degradable quaternary ammonium salt groups, which can greatly improve its alkali resistance stability. Polybenzimidazole (PBI) is a high-performance heterocyclic polymer with high thermal stability, excellent oxidation resistance and mechanical properties, and the preparation process is simple. The imidazole ring in the main chain has an amphiphilic nature, so it can be deprotonated by alkaline electrolytes, absorb electrolytes, and conduct ions. However, it needs to absorb high concentrations (10-35wt.%) of alkali solution to obtain higher ion conductivity, thereby ensuring high electrolyzer output efficiency. However, the doping of high concentrations of alkali will sharply reduce the mechanical properties of the membrane. Therefore, the current polybenzimidazole-based alkaline ion solvation membrane materials still need further technical improvements.

[0004] Introducing sulfonic acid groups on the molecular chain of polybenzimidazole can increase the ion transfer sites and significantly improve the ion conductivity of the ion solvation membrane material in low-concentration alkali solution. However, due to the water absorption of the sulfonic acid group, the membrane material has serious swelling problems and poor mechanical properties [Adv. Energy Mater. 2023, 2302966]. Therefore, controlling the dimensional stability of the sulfonated polybenzimidazole ion solvation membrane material is crucial to obtaining high-performance ion solvation membrane materials.

[0005] Chemical grafting or cross-linking modification of polybenzimidazole is an effective method to improve its mechanical properties, but this will also consume the active sites of the imidazole ring in its molecular structure, and the flexibility defects of the polymer chain segments cannot be overcome. Functionalized nanomaterials such as covalent organic frameworks (COFs) and covalent metal frameworks are incorporated into the polymer matrix. Among them, the covalent organic framework has highly ordered sub-nanometer pores inside, relevant functional groups can be pre-designed, and it has excellent chemical / thermal stability and dimensional stability, so it is an ideal platform for anion conduction. In recent years, the introduction of COF nanofillers in polymer matrices has been proven to be an effective way to improve the comprehensive performance of membranes, but it still faces the problem of compatibility between nanoparticles and polymer matrices. Summary of the invention

[0006] The present invention synthesizes sulfonated polybenzimidazole by a one-step method, and the preparation process is simple. The sulfonic acid group is directly introduced into the main chain molecule on the dicarboxylic acid monomer without occupying the active site of the imidazole ring. The present invention synthesizes the benzimidazole-based covalent organic framework in situ in the membrane by a thermally induced solvent volatilization method, which can effectively improve the mechanical properties and dimensional stability of the membrane. At the same time, the orderly arrangement of the benzimidazole groups can provide a fast channel for ion conduction. The main structural units of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane prepared by the present invention are all benzimidazole, and the polymer transitions from linear to grid ultra-high cross-linking, the membrane is homogeneous and transparent, and has strong compatibility, providing a new preparation method for alkaline ion solvation membrane. At the same time, the alkaline ion solvation membrane material (i.e., sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane) prepared by the present invention can be expanded to be applied in the field of alkaline water electrolysis, and can also be applied in the fields of energy conversion technology such as fuel cells, electric reduction of carbon dioxide, and zinc-air batteries, and has considerable application prospects.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention:

[0009] A sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane, prepared from sulfonated polybenzimidazole and benzimidazole-based covalent organic framework;

[0010] The structural formula of the sulfonated polybenzimidazole is shown in formula (1):

[0011]

[0012] Wherein, x represents the degree of sulfonation, 0<x≤80;

[0013] SAr1 is any one of the following structural units:

[0014]

[0015] Ar2 is any one of the following structural units:

[0016]

[0017] The benzimidazole-based covalent organic framework is synthesized from an aromatic trialdehyde monomer and an aromatic tetraamine monomer, wherein the aromatic trialdehyde monomer is any one of the following structures:

[0018]

[0019] The aromatic tetraamine monomer is any one of the following structures:

[0020]

[0021] The second technical solution of the present invention:

[0022] The present invention also provides a method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane, which comprises preparing the sulfonated polybenzimidazole by polymerization reaction, adding an aromatic trialdehyde monomer and an aromatic tetraamine monomer to a sulfonated polybenzimidazole solution to obtain a casting solution, preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane by heat-induced solvent evaporation of the casting solution, and subjecting the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane to alkali treatment to obtain the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane.

[0023] The present invention uses sulfonated polybenzimidazole as a polymer matrix, synthesizes a benzimidazole-based covalent organic framework in situ by a thermally induced solvent evaporation method, and prepares a composite alkaline ion solvation membrane with benzimidazole structural units as the main body. The sulfonic acid group on the polymer matrix can interact with the amino group, mediate the positioning to achieve long-range regular and orderly sub-nanometer pores, and the enrichment of the benzimidazole functional group can improve the hydroxide conductivity of the composite ion solvation membrane. At the same time, the benzimidazole-based covalent organic framework filler is generated in situ in the membrane, which can make it have good compatibility with the polybenzimidazole matrix, uniformity and enhanced membrane mechanical properties. In the present invention, both sulfonated polybenzimidazole and benzimidazole covalent organic frameworks have abundant ion transport sites, and the grid structure of the covalent organic framework can effectively control the dimensional stability of the membrane material, and the preparation method is simple, controllable and easy to scale up. The composite alkaline ion solvation membrane material prepared by the present invention has good application prospects in energy conversion fields such as alkaline water electrolysis, zinc-air batteries, carbon dioxide electroreduction, and ammonia fuel cells.

[0024] Preferably, the mass ratio of the total mass of the aromatic trialdehyde monomer and the aromatic tetraamine monomer to the mass of the sulfonated polybenzimidazole is (0.05-1):1.

[0025] Preferably, the preparation method of the sulfonated polybenzimidazole is: 3,3,4,4-diaminobenzidine is mixed with polyphosphoric acid, a dicarboxylic acid monomer containing SAr1 and Ar2 structures is added, the mixture is reacted at 100 to 220° C. for 12 to 48 hours, the mixture is washed with a saturated sodium bicarbonate solution and water until neutral, and then dried to obtain the sulfonated polybenzimidazole.

[0026] Preferably, in the method for preparing the sulfonated polybenzimidazole, the molar ratio of the total molar amount of the dicarboxylic acid monomer containing the SAr1 and Ar2 structures to 3,3,4,4-diaminobenzidine is 1:1.

[0027] Preferably, in the preparation method of the sulfonated polybenzimidazole, the drying is vacuum drying, the temperature of the vacuum drying is 60 to 100° C., and the time is 12 to 24 hours.

[0028] More preferably, the method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0029] Mixing 3,3,4,4-diaminobenzidine or 1,2,4,5-phenylenetetramine with polyphosphoric acid, adding dicarboxylic acid monomers containing SAr1 and Ar2 structures, reacting at 100 to 220° C. for 12 to 48 hours, washing with a saturated sodium bicarbonate solution and water until neutral, and drying to obtain the sulfonated polybenzimidazole;

[0030] The sulfonated polybenzimidazole is dissolved in a polar solvent to obtain a first solution, an aromatic tetraamine monomer is dissolved in a polar solvent to obtain a second solution, and then the first solution and the second solution are mixed to obtain a solution ①, an aromatic trialdehyde monomer is dissolved in a polar solvent to obtain a solution ②, and the solution ② is added dropwise into the solution ①, and stirred until fully mixed to obtain a casting solution, and the casting solution is prepared by heat-induced solvent evaporation to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0031] The sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is immersed in an alkaline solution, and after the immersion is completed, the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane is obtained.

[0032] Preferably, the polar solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0033] Preferably, the alkaline solution includes one of potassium hydroxide solution, potassium carbonate solution, potassium bicarbonate solution, sodium hydroxide solution, sodium carbonate solution and sodium bicarbonate solution.

[0034] More preferably, the concentration of the alkaline solution is 1 to 15 mol / L.

[0035] Preferably, the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is immersed in the alkaline solution at a temperature of 50 to 80° C. for 72 to 100 hours.

[0036] Preferably, the solid content of the casting solution is 3 to 5 wt.%.

[0037] Preferably, the process of preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane by heat-induced solvent evaporation is as follows: pouring the mixed film casting solution into a glass plate mold, and the ratio of the total mass of all polymers in the film casting solution to the mold area is 0.5 g / 25 cm 2 , then reacting at 60° C. for 24 hours, then reacting at 80° C. for 12 to 24 hours, and finally reacting at 100° C. for 12 to 24 hours to obtain the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane.

[0038] The third technical solution of the present invention:

[0039] The present invention also provides the application of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane in the field of energy conversion technology, including the alkaline water electrolysis field, the fuel cell field, the electric reduction of carbon dioxide field or the zinc-air battery field.

[0040] Compared with the prior art, the present invention has the following advantages and technical effects:

[0041] (1) The sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane of the present invention has benzimidazole as the main structural unit, and the polymer undergoes a transition from linear to grid ultra-high cross-linking. The membrane is homogeneous and transparent and has strong compatibility.

[0042] (2) The sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane of the present invention introduces sulfonic acid groups into the molecular chain of polybenzimidazole, which can increase the ion transmission sites and greatly improve the ion conductivity of the ion solvation membrane material in low-concentration alkaline solution.

[0043] (3) The sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane of the present invention introduces a covalent organic framework (COF) with highly ordered subnanometer pores and dimensional stability, which can control the water absorption and swelling rate of the composite membrane.

[0044] (4) The preparation method of the present invention is simple and efficient. At the same time, the alkaline ion solvation composite membrane material prepared by the present invention can be applied to energy conversion technologies such as fuel cells, electroreduction of carbon dioxide, and zinc-air batteries in addition to being used in alkaline electrolyzers, and has considerable application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0046] Figure 1 This is a hydrogen nuclear magnetic resonance spectrum of the sulfonated polybenzimidazole SNPBI-20% prepared in Example 1 of the present invention;

[0047] Figure 2 This is a scanning electron microscope image of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane prepared in Example 1 of the present invention;

[0048] Figure 3 This is a scanning electron microscope image of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane prepared in Example 2 of the present invention;

[0049] Figure 4 The H NMR spectrum of the sulfonated polybenzimidazole SNPBI-60% prepared in Example 6 of the present invention ( 1 HNMR) spectra;

[0050] Figure 5 This is the hydrogen nuclear magnetic resonance spectrum of the sulfonated polybenzimidazole SPBI-20% prepared in Example 7 of the present invention;

[0051] Figure 6 This is the hydrogen nuclear magnetic resonance spectrum of the sulfonated polybenzimidazole SPBI-60% prepared in Example 11 of the present invention;

[0052] Figure 7 Polarization curves of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane prepared in Examples 1 to 7 of the present invention in an alkaline water electrolysis device. DETAILED DESCRIPTION

[0053] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0054] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0055] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0056] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0057] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0058] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0059] All raw materials used in the examples of the present invention are commercially available.

[0060] The technical solution of the present invention is further illustrated by the following embodiments.

[0061] Example 1

[0062] A method for preparing a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0063] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 80°C for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.133g (0.8mmol) of 2-sulfonato monosodium terephthalate and 0.864g (3.2mmol) of 1,4-naphthalene dicarboxylic acid, heat to 100°C and maintain for 24h. The reaction solution is viscous. After the reaction is completed, pour the polymer product into deionized water while it is hot and filter it. Then, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80°C for 12h to obtain sulfonated polybenzimidazole SNPBI, which is recorded as SNPBI-20% (sulfonation degree is 20%). The product was subjected to 1 HNMR characterization, the results are as follows Figure 1 shown.

[0064] The structural formula of the prepared sulfonated polybenzimidazole is as follows:

[0065]

[0066] (2) Take 0.0625g of SNPBI-20% and dissolve it in dimethyl sulfoxide to prepare a SNPBI-20% solution with a concentration of 3wt.%, take 0.0375g of 3,3,4,4-diaminobenzidine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, and then add it to the SNPBI-20% solution. The resulting mixture is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.025g of 1,3,5-tri(4-formylphenyl)benzene and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 3wt.%) into a glass plate mold. The ratio of the total mass of all polymers in the solution to the mold area is 0.5g / 25cm 2 , then react at 60°C for 24h, then at 80°C for 12h, and finally at 100°C for 12h to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0067] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0068]

[0069] Scanning electron microscopy was used to analyze the cross-sectional structure of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membranes, such as Figure 2 shown.

[0070] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a 6 mol / L potassium hydroxide (KOH) solution for 72 h at a temperature of 50°C to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. The membrane was subjected to a water absorption and swelling test at 80°C, and its water absorption rate was measured to be 11.51% and its swelling rate was 3.72%. The ionic conductivity of the membrane was tested at 80°C in a 6 mol / L KOH solution, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 235.33 mS / cm.

[0071] Example 2

[0072] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0073] (1) The preparation of sulfonated polybenzimidazole SNPBI is the same as in Example 1, and the degree of sulfonation is the same as in Example 1.

[0074] (2) Take 0.0625g SNPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, take 0.0375g 3,3,4,4-diaminobenzidine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, then add it to the sulfonated polybenzimidazole solution, and the resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.025g 1,3,5-benzenetricarboxaldehyde and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 3wt.%) into a glass plate mold. The ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 12 hours, and finally at 100°C for 20 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0075] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0076]

[0077] Scanning electron microscopy was used to analyze the cross-sectional structure of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membranes, such as Figure 3 shown.

[0078] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 8 mol / L for 100 h at a temperature of 60°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. The membrane was subjected to a water absorption and swelling test at 80°C, and its water absorption rate was measured to be 12.01% and its swelling rate was 3.78%. The ionic conductivity of the membrane was tested at 80°C in a 6 mol / L potassium hydroxide solution, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 256.93 mS / cm.

[0079] Example 3

[0080] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0081] (1) The preparation of sulfonated polybenzimidazole SNPBI is the same as in Example 1, and the degree of sulfonation is the same as in Example 1.

[0082] (2) Take 0.0625g SNPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, take 0.0375g 1,2,4,5-benzenetetramine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, and then add it to the sulfonated polybenzimidazole solution. The resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.025g 1,3,5-trimethyl-2,4,6-formaldehyde benzene and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 3wt.%) into a glass plate mold. The ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 18 hours, and finally at 100°C for 18 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0083] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0084]

[0085] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 2 mol / L for 100 h at a temperature of 80°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. Under the condition of 80°C, the above membrane was subjected to a water absorption and swelling test, and its water absorption rate was measured to be 12.47% and its swelling rate was 4.25%. The above membrane was subjected to an ionic conductivity test in a 6 mol / L potassium hydroxide solution at 50°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 228.91 mS / cm.

[0086] Example 4

[0087] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0088] (1) The preparation of sulfonated polybenzimidazole SNPBI is the same as in Example 1, and the degree of sulfonation is the same as in Example 1.

[0089] (2) Take 0.0625g SNPBI (20%) and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 4wt.%, take 0.0375g 1,2,4,5-benzenetetramine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 4wt.%, then add it to the sulfonated polybenzimidazole solution, and the resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.025g 1,3,5-trihydroxy-2,4,6-trialdehyde benzene and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 4wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 4wt.%) into a glass plate mold, and the ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 12 hours, and finally at 100°C for 20 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0090] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0091]

[0092] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 5 mol / L; the immersion time was 80 h and the temperature was 80°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. Under the condition of 80°C, the above membrane was subjected to a water absorption and swelling test, and its water absorption rate was measured to be 12.34% and its swelling rate was 4.62%. The above membrane was subjected to an ionic conductivity test in a 6 mol / L potassium hydroxide solution at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 218.38 mS / cm.

[0093] Example 5

[0094] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0095] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 80°C for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.266g (1.6mmol) of 2-sulfonato terephthalic acid monosodium, and 0.648g (2.4mmol) of 1,4-naphthalenedicarboxylic acid, and heat to 180°C for 36h. When the reaction solution becomes viscous, pour the polymer product into a large amount of deionized water while hot to wash away most of the acid, wash with saturated sodium bicarbonate solution and deionized water until neutral, and then dry at 80°C for 12h to obtain sulfonated polybenzimidazole SNPBI-40%.

[0096] The structural formula of sulfonated polybenzimidazole is as follows:

[0097]

[0098] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0099] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0100]

[0101] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 10 mol / L; the immersion time was 80 h and the temperature was 60°C, thus obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. Under the condition of 80°C, the above membrane was subjected to a water absorption and swelling test, and its water absorption rate was measured to be 13.17% and its swelling rate was 4.72%. The ionic conductivity of the membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 246.21 mS / cm.

[0102] Example 6

[0103] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0104] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.399g (2.4mmol) of 2-sulfonato monosodium terephthalate, and 0.432g (1.6mmol) of 1,4-naphthalene dicarboxylic acid, heat to 180℃ and react for 45h. The reaction liquid is viscous. After the reaction is completed, pour the polymer product into deionized water while it is hot to wash off most of the acid, wash with saturated sodium bicarbonate solution and deionized water until neutral, and dry at 80℃ for 20h to obtain sulfonated polybenzimidazole SNPBI-60%. The product was subjected to 1 HNMR characterization, the results are shown in Figure 4 .

[0105] The structural formula of sulfonated polybenzimidazole is as follows:

[0106]

[0107] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 3.

[0108] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0109]

[0110] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 1 mol / L; the immersion time was 80 h and the temperature was 80°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 258.18 mS / cm.

[0111] Example 7

[0112] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0113] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.133g (0.8mmol) of 2-sulfonato monosodium terephthalate, and 0.532g (3.2mmol) of terephthalic acid, heat to 160℃ and react for 24h. When the reaction liquid becomes viscous, pour the polymer product into deionized water while hot to wash away most of the acid, wash with saturated sodium bicarbonate solution and deionized water until neutral, and dry at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%. The product was subjected to 1 HNMR characterization, see Figure 5 .

[0114] The structural formula of sulfonated polybenzimidazole is as follows:

[0115]

[0116] (2) Take 0.0625g SPBI (20%) and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 5wt.%, take 0.0375g 3,3,4,4-diaminobenzidine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 5wt.%, then add it to the sulfonated polybenzimidazole solution, and the resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, recorded as solution ①. Take 0.025g 1,3,5-tri(4-formylphenyl)benzene and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 5wt.%, recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 5wt.%) into a glass plate mold. The ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 12 hours, and finally at 100°C for 20 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0117] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0118]

[0119] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 60°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 250.76 mS / cm.

[0120] Example 8

[0121] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0122] (1) The preparation of sulfonated polybenzimidazole SPBI is the same as in Example 8, and the degree of sulfonation is the same as in Example 8.

[0123] (2) Take 0.0625g of SPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 4wt.%, take 0.0375g of 3,3,4,4-diaminobenzidine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 4wt.%, then add it to the sulfonated polybenzimidazole solution, and the resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, recorded as solution ①. Take 0.025g of 1,3,5-benzenetricarboxaldehyde and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 4wt.%, recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 4wt.%) into a glass plate mold. The ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 48 hours, and finally at 100°C for 48 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0124] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0125]

[0126] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 1 mol / L; the immersion time was 100 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 269.93 mS / cm.

[0127] Example 9

[0128] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0129] (1) The preparation of sulfonated polybenzimidazole SPBI is the same as in Example 8, and the degree of sulfonation is the same as in Example 8.

[0130] (2) Take 0.625g of SPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, take 0.00375g of dibenzo[b,e][1,4]dioxopyrimidine-2,3,7,8-tetramine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, then add it to the sulfonated polybenzimidazole solution, and the resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.0025g of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine and dissolve it in N-methylpyrrolidone to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained casting solution (solid content of 3wt.%) into a glass plate mold, and the ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, then at 80°C for 12 hours, and finally at 100°C for 24 hours to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane;

[0131] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0132]

[0133] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 10 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 258.07 mS / cm.

[0134] Example 10

[0135] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0136] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.266g (1.6mmol) of 2-sulfonato terephthalic acid monosodium, and 0.399g (2.4mmol) of terephthalic acid, heat to 200℃, and react for 36h. When the reaction solution becomes viscous, pour the polymer product into deionized water while hot to wash away most of the acid, wash with saturated sodium bicarbonate solution and deionized water until neutral, and then dry at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-40.

[0137] The structural formula of sulfonated polybenzimidazole is as follows:

[0138]

[0139] (2) Preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1;

[0140] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0141]

[0142] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 15 mol / L; the immersion time was 72 h and the temperature was 80°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 263.44 mS / cm.

[0143] Embodiment 11

[0144] Preparation of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane:

[0145] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.399g (2.4mmol) of 2-sulfonato monosodium terephthalate, and 0.266g (1.6mmol) of terephthalic acid, raise the temperature to 200℃, and react for 48h. When the reaction solution becomes viscous, pour the polymer product into deionized water while hot to wash away most of the acid, wash with saturated sodium bicarbonate solution and deionized water until neutral, and dry at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-60%. The product was subjected to 1 HNMR characterization, see Figure 6 .

[0146] The structural formula of sulfonated polybenzimidazole is as follows:

[0147]

[0148] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as Example 10.

[0149] The structural formula of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is as follows:

[0150]

[0151] (3) The prepared sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane was immersed in a potassium hydroxide solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 60°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane. The ion conductivity of the above membrane was tested in a 6 mol / L potassium hydroxide solution at 80°C, and the ion conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 266.81 mS / cm.

[0152] Example 12

[0153] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0154] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.922g (3.438mmol) of sodium 5-sulfoisophthalic acid, and 0.864g (3.2mmol) of 1,4-naphthalenedicarboxylic acid. Set a program to increase the temperature from 100℃ to 200℃, increase the temperature by 20℃ every two hours, and maintain the temperature for 48h when it reaches 200℃. The reaction liquid is viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0155] The structural formula of sulfonated polybenzimidazole is as follows:

[0156]

[0157] (2) Take 0.0625g of SPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, take 0.00375g of 2,3,7,8-phenazinetetramine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, and then add it to the sulfonated polybenzimidazole solution. The resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.0025g of 1,3,5-tri(p-formylphenylvinyl)benzene and dissolve it in N,N-dimethylformamide to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained mixed casting solution (solid content of 3wt.%) into a glass plate mold. The ratio of the total mass of all polymers in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, at 80°C for 12 hours, and at 100°C for 12 hours to obtain a benzimidazole-based covalent organic framework composite membrane;

[0158] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0159]

[0160] (3) The prepared composite membrane material was immersed in a sodium hydroxide solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 250.33 mS / cm.

[0161] Example 13

[0162] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0163] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.275g (0.8mmol) of 4,4'-biphenyl dicarboxylic acid-3-sulfonate sodium, and 0.666g (3.2mmol) of 2,4,6-trimethyl-1,3-benzenedicarboxylic acid. Set a program to increase the temperature from 100℃ to 200℃, increase the temperature by 20℃ every two hours, and maintain the temperature for 48h when it reaches 200℃. The reaction solution is viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0164] The structural formula of sulfonated polybenzimidazole is as follows:

[0165]

[0166] (2) Take 0.0625g of SPBI-20% and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, take 0.01875g of 2,3,7,8-phenazinetetramine and dissolve it in dimethyl sulfoxide to prepare a solution with a concentration of 3wt.%, and then add it to the sulfonated polybenzimidazole solution. The resulting solution is a mixed solution of aromatic tetraamine monomer and sulfonated polybenzimidazole, which is recorded as solution ①. Take 0.0125g of tri(4-formylphenyl)amine and dissolve it in N,N-dimethylacetamide to prepare a solution with a concentration of 3wt.%, which is recorded as solution ②. Add solution ② dropwise into solution ①, stir until fully mixed, and then pour the obtained mixed casting solution (solid content of 3wt.%) into a glass plate mold. The ratio of all polymers and total mass in the solution to the mold area is 0.5g / 25cm 2 Then, the reaction was carried out at 60°C for 24 hours, at 80°C for 12 hours, and at 100°C for 12 hours to obtain a benzimidazole-based covalent organic framework composite membrane;

[0167] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0168]

[0169] (3) The prepared composite membrane material was immersed in a potassium carbonate solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 236.29 mS / cm.

[0170] Embodiment 14

[0171] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0172] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3',4,4'-diaminobenzidine, 0.309g (0.8mmol) of 4,4'-(methylethylene)bis[benzoic acid]-3-sulfonate sodium, and 0.909g (3.2mmol) of 4,4'-(methylethylene)bis[benzoic acid], set the temperature program, and increase the reaction temperature from 100℃ to 200℃, increasing the temperature by 20℃ every two hours. When the temperature reaches 200℃, maintain it for 48h, and the reaction liquid becomes viscous. After the reaction is completed, pour the polymer product into a large amount of deionized water while hot to wash away most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0173] The structural formula of sulfonated polybenzimidazole is as follows:

[0174]

[0175] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0176] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0177]

[0178] (3) The prepared composite membrane material was immersed in a potassium bicarbonate solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 236.78 mS / cm.

[0179] Embodiment 15

[0180] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0181] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3',4,4'-diaminobenzidine, 0.395g (0.8mmol) of 2,2-bis(4-carboxyphenyl)hexafluoropropane sulfonate sodium, and 1.255g (3.2mmol) of 2,2-bis(4-carboxyphenyl)hexafluoropropane, set a program temperature rise, the reaction temperature increases from 100℃ to 200℃, and the temperature rises by 20℃ every two hours. When the temperature reaches 200℃, maintain it for 48h, and the reaction liquid becomes viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0182] The structural formula of sulfonated polybenzimidazole is as follows:

[0183]

[0184] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0185] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0186]

[0187] (3) The prepared composite membrane material was immersed in a sodium carbonate solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 264.79 mS / cm.

[0188] Example 16

[0189] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0190] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.294g (0.8mmol) of 9,10-anthracene dicarboxylic acid-2-sulfonic sodium, and 1.210g (3.2mmol) of 2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-dicarboxylic acid, set a temperature program, and increase the reaction temperature from 100℃ to 200℃, increasing the temperature by 20℃ every two hours. When the temperature reaches 200℃, maintain it for 48h, and the reaction liquid becomes viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0191] The structural formula of sulfonated polybenzimidazole is as follows:

[0192]

[0193] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0194] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0195]

[0196] (3) The prepared composite membrane material was immersed in a potassium carbonate solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 236.29 mS / cm.

[0197] Embodiment 17

[0198] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0199] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.254g (0.8mmol) of 2,6-naphthalene dicarboxylic acid-1-sulfonic sodium, and 1.018g (3.2mmol) of 2,5-diphenyl terephthalic acid. Set a program to increase the temperature from 100℃ to 200℃, increase the temperature by 20℃ every two hours, and maintain the temperature for 48h when it reaches 200℃. The reaction liquid is viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0200] The structural formula of sulfonated polybenzimidazole is as follows:

[0201]

[0202] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0203] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0204]

[0205] (3) The prepared composite membrane material was immersed in a sodium bicarbonate solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 252.22 mS / cm.

[0206] Embodiment 18

[0207] A preparation method of a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane comprises the following steps:

[0208] (1) Add 50g of polyphosphoric acid to a 100mL three-necked flask, stir and heat at 100℃ for 2h in a N2 atmosphere to eliminate bubbles, then add 0.86g (4.00mmol) of 3,3,4,4-diaminobenzidine, 0.254g (0.8mmol) of 1,4-naphthalene dicarboxylic acid-6-sulfonate sodium, and 0.852g (3.2mmol) of 9,10-anthracene dicarboxylic acid. Set the temperature program to increase the reaction temperature from 100℃ to 200℃, increase the temperature by 20℃ every two hours, and maintain the temperature for 48h when it reaches 200℃. The reaction liquid is viscous. After the reaction is completed, pour the polymer product into deionized water while hot to wash off most of the acid, wash it with saturated sodium bicarbonate solution and deionized water until it is neutral, and then dry it at 80℃ for 12h to obtain sulfonated polybenzimidazole SPBI-20%.

[0209] The structural formula of sulfonated polybenzimidazole is as follows:

[0210]

[0211] (2) The preparation of sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is the same as in Example 1.

[0212] The structural formula of the benzimidazole-based covalent organic framework composite membrane is as follows:

[0213]

[0214] (3) The prepared composite membrane material was immersed in a potassium hydroxide solution with a concentration of 6 mol / L; the immersion time was 72 h and the temperature was 50°C, thereby obtaining a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane material. The ionic conductivity of the membrane was tested at 80°C, and the ionic conductivity of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane was 253.33 mS / cm.

[0215] Figure 7 Polarization curves (60° C., 6 mol / L KOH solution) of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane prepared in Examples 1 to 7 of the present invention in an alkaline water electrolysis device.

[0216] The mechanical properties of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membranes prepared in Examples 1 to 18 of the present invention were measured using a thin film tensile test method (refer to GB 13022-1991). The results are shown in Table 1.

[0217] Table 1

[0218]

[0219]

[0220] Note: In the above tests, GB / T 20042.3-2022 was used to test the water absorption and swelling rate of the membrane; an electrochemical workstation (Bio-Logic VSP-300) was used to measure the conductivity using the double-electrode method.

[0221] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane, characterized in that: Prepared from sulfonated polybenzimidazole and benzimidazole-based covalent organic framework; The structural formula of the sulfonated polybenzimidazole is shown in formula (1): Wherein, x represents the degree of sulfonation, 0<x≤80; SAr1 is any one of the following structural units: Ar2 is any one of the following structural units: The benzimidazole-based covalent organic framework is synthesized from an aromatic trialdehyde monomer and an aromatic tetraamine monomer, wherein the aromatic trialdehyde monomer is any one of the following structures: The aromatic tetraamine monomer is any one of the following structures:

2. A method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 1, characterized in that: Sulfonated polybenzimidazole is prepared by polymerization reaction, and aromatic trialdehyde monomer and aromatic tetraamine monomer are added to the sulfonated polybenzimidazole solution to obtain a casting solution. The casting solution is subjected to heat-induced solvent evaporation to prepare a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane, and the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is subjected to alkali treatment to obtain the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane.

3. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 2, characterized in that: The mass ratio of the total mass of the aromatic trialdehyde monomer and the aromatic tetraamine monomer to the mass of the sulfonated polybenzimidazole is (0.05-1):

1.

4. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 2, characterized in that: The preparation method of the sulfonated polybenzimidazole is as follows: 3,3,4,4-diaminobenzidine or 1,2,4,5-phenyltetramine is mixed with polyphosphoric acid, a dicarboxylic acid monomer containing SA1 and Ar2 structures is added, the mixture is reacted at 100 to 220° C. for 12 to 48 hours, the mixture is washed with a saturated sodium bicarbonate solution and water until neutral, and then dried to obtain the sulfonated polybenzimidazole.

5. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 4, characterized in that: The molar ratio of the total molar amount of the dicarboxylic acid monomers containing the SA1 and Ar2 structures to 3,3,4,4-diaminobenzidine is 1:(1-1.5).

6. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 4, characterized in that: The drying is vacuum drying, the temperature of the vacuum drying is 60-100° C., and the time is 12-24 hours.

7. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 2, characterized in that: The following steps are involved: Mixing 3,3,4,4-diaminobenzidine and polyphosphoric acid, adding dicarboxylic acid monomers containing SAr1 and Ar2 structures, reacting at 100 to 220° C. for 12 to 48 hours, washing with saturated sodium bicarbonate solution and water until neutral, and drying to obtain the sulfonated polybenzimidazole; The sulfonated polybenzimidazole is dissolved in a polar solvent to obtain a first solution, an aromatic tetraamine monomer is dissolved in a polar solvent to obtain a second solution, and then the first solution and the second solution are mixed to obtain a solution ①, an aromatic trialdehyde monomer is dissolved in a polar solvent to obtain a solution ②, and the solution ② is added dropwise into the solution ①, and stirred until fully mixed to obtain a casting solution, and the casting solution is prepared by heat-induced solvent evaporation to obtain a sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane; The sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite membrane is immersed in an alkaline solution, and after the immersion is completed, the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane is obtained.

8. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 7, characterized in that: The polar solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

9. The method for preparing the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 7, characterized in that: The alkaline solution includes one of potassium hydroxide solution, potassium carbonate solution, potassium bicarbonate solution, sodium hydroxide solution, sodium carbonate solution and sodium bicarbonate solution.

10. Application of the sulfonated polybenzimidazole / benzimidazole-based covalent organic framework composite alkaline ion solvation membrane according to claim 1 in the field of energy conversion technology, characterized in that: Including the fields of alkaline water electrolysis, fuel cells, carbon dioxide electroreduction or zinc-air batteries.

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