A polyazulene sulfide anion exchange membrane, a preparation method and application thereof

Abstract

The application discloses a preparation method and application of a polyazulene sulfide, relates to the technical field of membranes, and comprises the following steps: preparing a polyazulene sulfide polymer; and preparing a polyazulene sulfide anion exchange membrane. Thus, a basic anion exchange membrane is prepared through polymerization and quaternization, wherein a strong dipole moment azulene group and a sulfur-containing main chain promote the formation of a strengthened hydrogen bond network, promote the high-speed transmission of OH ‑ , a branched structure generates high mechanical strength, greatly reduces the water absorption and swelling rate of the anion exchange membrane, and thus improves the dimensional stability; meanwhile, high-stability cation groups and nucleophilic azulene groups increase the basic stability, the high OH ‑ conductivity, the basic stability and the high mechanical strength indicate that the prepared polyazulene sulfide anion exchange membrane can be used as an anion exchange membrane material for a basic fuel cell and a basic electrolytic cell.

Description

Technical Field

[0001] This application relates to the field of membrane technology, and in particular to a polyazine sulfide anion exchange membrane, its preparation method, and its application. Background Technology

[0002] Due to global development and population growth, global energy demand continues to grow rapidly. Green hydrogen can be produced through water electrolysis technology driven by the overcapacity of solar and wind power generation, with fuel cells being the primary application of hydrogen energy. Currently, proton exchange membrane fuel cells and acidic electrolyzers, operating under acidic conditions, require precious metal catalysts and expensive proton exchange membranes, resulting in excessively high costs for hydrogen production and utilization, significantly hindering industrial development. Anion exchange membrane fuel cells and alkaline water electrolysis technology can use low-alkaline electrolytes and non-precious metal catalysts, greatly reducing operating costs and thus attracting widespread attention.

[0003] Anion exchange membranes (AEMs) are a key component of anion exchange membrane fuel cells and alkaline electrolyzers. Preparing anion exchange membranes with high hydroxide ion conductivity and stable chemical properties is crucial for achieving high power density and long-term durability in anion exchange membrane fuel cells and alkaline electrolyzers. Anion exchange membranes consist of a polymer backbone, cationic groups, and migratable ions. The polymer backbone structure and the properties of the cationic groups directly determine the performance of the AEM. Current research on AEMs still faces the following technical bottlenecks: (1) Due to OH... - radius ratio H + The radius is large, and OH in AEM - The conductivity is only that of H in a proton exchange membrane under the same conditions. + The conductivity is 20% to 33%. However, the most direct way to improve the conductivity is to increase the ion exchange capacity (IEC). Increasing the IEC means that more hydrophilic cationic groups need to be introduced, which will lead to an increase in membrane water absorption and swelling, thereby causing a decrease in the mechanical properties of the membrane. Therefore, solving the “trade-off” effect between the ionic conductivity and dimensional stability of the membrane is crucial for the development of AEM. (2) Under hot alkaline working conditions, the polymer backbone and cationic groups are susceptible to nucleophilic OH groups. - The attack of the membrane causes complex degradation reactions in the main chain structure and cationic groups, which leads to a decrease in membrane performance and even reduces the service life of the AEM.

[0004] Therefore, improving the alkali stability of AEM and extending the membrane's service life are urgent problems to be solved. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems in the prior art, this application provides a polyazine sulfide anion exchange membrane, its preparation method and application, so as to overcome the problems of low ion conductivity and poor alkali stability of AEM in the prior art.

[0006] To achieve the above objectives, the technical solution of this application embodiment is as follows:

[0007] The first aspect of this application provides a polyazine sulfide anion exchange membrane, wherein the polyazine sulfide anion exchange membrane contains a polyazine sulfide polymer and has the following structure:

[0008]

[0009] Wherein, R1 is a cationic group, R2 is a branched group, a is any integer between 1 and 10000, and b is any integer between 0 and 10000.

[0010] Preferably, in conjunction with the first aspect, R1 is at least one of the following structures:

[0011]

[0012] Where n is an integer greater than or equal to 0.

[0013] Preferably, in conjunction with the first aspect, R2 is at least one of the following structures (matching R2 in the above general formula in terms of the number of its connecting keys):

[0014]

[0015]

[0016]

[0017] A second aspect of this application provides a method for preparing the polyazine sulfide anion exchange membrane described in the first aspect, the method comprising:

[0018] (1) Preparation of polyazine sulfide polymer:

[0019] Na2S, azulene monomer A as shown in Formula 1, and branched monomer R2-Br were placed in a reaction vessel, dissolved in a first organic solvent, and the mixture was rapidly heated to carry out the reaction. The solid product was then washed, dried, and collected. The product was then dissolved in a second organic solvent, potassium carbonate and iodomethane were added, and the mixture was reacted in the dark. Ethyl acetate was added, and the mixture was purified to collect the polyazine sulfide polymer.

[0020]

[0021] (2) Preparation of polyazine sulfide anion exchange membrane:

[0022] The polyazine sulfide polymer is dissolved in a second organic solvent, dried, and then I is collected. - Type I thin film, making the I - Ion exchange is performed on a thin film to obtain OH-. - After purification, the polyazine sulfide anion exchange membrane was collected.

[0023] Preferably, in conjunction with the second aspect, the molar ratio of the sum of the amounts of the azulene monomer and the branched monomer to the amount of Na2S added is 1:0.9-1.5.

[0024] In conjunction with the second aspect, preferably, the reaction temperature is greater than 150°C and the reaction time is greater than 4 hours.

[0025] Preferably, in conjunction with the second aspect, the first organic solvent is one or more of dimethyl sulfoxide, N-methylpyrrolidone, and N,N-dimethylformamide.

[0026] Preferably, in conjunction with the second aspect, the second organic solvent is one or more of acetonitrile, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, and sulfolane.

[0027] A third aspect of this application provides a polyazine sulfide anion exchange membrane as described in the first aspect, and the application of the polyazine sulfide anion exchange membrane prepared by the method described in the second aspect in the preparation of alkaline fuel cells and alkaline electrolyzers.

[0028] Compared with the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following:

[0029] The polyazine sulfide anion exchange membrane provided in this application is a basic anion exchange membrane prepared by polymerization and quaternization. The strong dipole moment azulene groups and sulfur-containing backbone promote the formation of a strengthened hydrogen bond network, thus enhancing the OH- ion exchange capacity. - High-speed transport; the branched structure generates high mechanical strength, greatly reducing the water absorption and swelling rate of the anion exchange membrane, thereby improving dimensional stability; at the same time, the highly stable cationic groups and nucleophilic azurite groups increase its basic stability, and its high OH... - The conductivity, alkalinity stability, and high mechanical strength indicate that the polyazine sulfide anion exchange membrane prepared in this application can be used as anion exchange membrane material for alkaline fuel cells and alkaline electrolyzers.

[0030] The polyazine sulfide anion exchange membrane provided in this application has high OH content. - Conductivity (at 80℃, OH) - Conductivity > 100 mS cm -1It exhibits high mechanical strength (tensile strength >35MPa, elongation at break >10%), high dimensional stability, good processing performance, and excellent alkaline stability (>500h) in 1M KOH at 80℃.

[0031] Compared to other types of branched poly(aryl-piperidine) anion exchange membranes, the strong dipole moment azulene groups and sulfur-containing backbone in its molecular structure promote the formation of a stronger hydrogen bond network, thus facilitating the OH- ion exchange. - High-speed transport; the introduction of nucleophilic azurite groups makes the structure less susceptible to OH groups. - The attack enhances its alkaline stability; the formation of branched structures causes the molecular chains to become entangled, enhancing its mechanical properties. Attached Figure Description

[0032] Figure 1 Synthetic pathway diagram of 6-6'-biazine crosslinked poly(6-piperidinazine sulfide) (b-PAS-6Pip-BiAz) provided in this application

[0033] Figure 2 Synthesis pathway diagram of b-PAS-6pip-3AzPh provided in this application.

[0034] Figure 3 Synthetic pathway diagram for poly(6-piperidinylazine sulfide) (PAS-6pip) provided in this application.

[0035] Figure 4 The polyazine sulfide anion exchange membranes prepared in Examples 1, 2, and 3 (OH) - Conductivity test results.

[0036] Figure 5 The results of water electrolysis tests on the polyazine sulfide anion exchange membranes prepared in Examples 1, 2 and 3 are shown. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] In the following description, references to "some embodiments" refer to a subset of all possible embodiments. However, it is understood that "some embodiments" may be the same or different subsets of all possible embodiments and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this application pertain. The terminology used in the embodiments of this application is for the purpose of describing the embodiments of this application only and is not intended to limit the application.

[0039] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0040] It should be noted that all raw materials / reagents in the embodiments of this application can be purchased on the market or prepared according to conventional methods known to those skilled in the art; the term "and / or" in the embodiments of this application is only used to describe the relationship between related objects, indicating that there can be three relationships. For example, A and / or B means three cases: A exists alone, B exists alone, and A and B exist simultaneously. A and B can be singular or plural. The character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0041] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0042] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0043] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0044] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value and an intermediate value within the stated range, as well as any other stated value or an intermediate value within the stated range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0045] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art described herein. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in embodiments or test examples of this application. All references to this specification are generally incorporated herein by reference to disclose and describe methods and / or materials associated with said references. In the event of any conflict with any incorporated references, the content of this application shall prevail.

[0046] It should be noted that all raw materials and / or reagents in the embodiments of this application were purchased on the market or prepared according to conventional methods known to those skilled in the art.

[0047] The following are the testing methods used in the examples:

[0048] Performance testing:

[0049] The equipment and testing methods involved in the embodiments:

[0050] Ion exchange capacity (IEC) test method: Take Cl from polyazine sulfide polymer - Type or Br - The membrane was dried in a vacuum oven at 75°C and its mass was recorded. The dried membrane was then immersed in 25 mL of 0.2 M NaNO3 solution for 6 hours, repeated three times, and the NaNO3 solution after ion exchange was collected. Potassium chromate solution was added to this solution, and titration was performed with 0.01 M AgNO3 standard solution. The titration was complete when a brick-red precipitate appeared and did not disappear after shaking. The volume of AgNO3 solution consumed was recorded. The product of the AgNO3 solution concentration and volume, divided by the mass of the dried membrane, is the IEC (interval between concentration and volume).

[0051] OH -Conductivity testing: The electrochemical workstation used was a CHI660E manufactured by Shanghai Chenhua Instrument Co., Ltd. The electrochemical impedance spectroscopy (EIS) method was employed to test the membrane conductivity at different temperatures. The measured potential amplitude was 10 mV. To minimize the error caused by contact resistance, the resistance measured was the in-plane resistance of the membrane sample. In the experiment, the membrane was cut into 40 mm × 10 mm pieces, placed in a fixture, and the fixture was placed in pure water. The test temperature ranged from 30℃ to 80℃, with membrane resistance measured every 10℃. The membrane was kept at this temperature for 1 hour before each test. Finally, the ionic conductivity σ of the sample was calculated using the formula: σ = l / (wdR), where l is the length of the membrane between electrodes (cm), w is the width of the membrane (cm), d is the thickness of the membrane (μm), and R is the measured membrane resistance (mΩ).

[0052] Anion exchange membrane water electrolysis performance test: Anode is loaded with IrO2 (1 mg / cm³) 2 The titanium felt cathode is loaded with 10 wt% Pt / C (1 mg / cm³). 2 The carbon paper has an electrode area of ​​4 cm². 2 An MEA electrolytic cell was assembled using 1M KOH as the electrolyte, with a circulation rate of 20 mL / min and a test temperature of 60℃. A CHI660e instrument was used to perform a 0-2.5V linear voltammetric scan on the electrolytic cell.

[0053] Tensile strength test: The dry film sample of 5×0.5cm was tested using an Instron M3300 electronic universal testing machine at a tensile rate of 5mm / min.

[0054] Alkali stability test: The prepared anion exchange membrane was immersed in NaOH solutions of different temperatures and concentrations, and its conductivity was measured simultaneously. The alkali stability was analyzed by the change in the conductivity of the electrolyte membrane. The alkali stability time was defined as the time for the conductivity to remain at 90% of the initial conductivity after immersion in 1 M KOH at 80℃.

[0055] Swelling rate test: After vacuum drying at 80℃, the dry weight (W) of the membrane sample was recorded. dry ) and length (L) dry Then, the samples were immersed in deaerated deionized water for 12 hours at different temperatures. After wiping off excess moisture from the surface, the wet weight (W) of the samples was recorded. wet ) and length (L) wet The water content and swelling degree can be calculated using the following formulas:

[0056]

[0057] In a first aspect, embodiments of this application provide a polyazine sulfide anion exchange membrane, wherein the polyazine sulfide anion exchange membrane contains a polyazine sulfide polymer and has the following structure:

[0058]

[0059] Wherein, R1 is a cationic group, R2 is a branched group, a is any integer between 1 and 10000, and b is any integer between 0 and 10000.

[0060] The polyazine sulfide anion exchange membrane provided in this application is a basic anion exchange membrane prepared by polymerization and quaternization. The strong dipole moment azulene groups and sulfur-containing backbone promote the formation of a strengthened hydrogen bond network, thus enhancing the OH- ion exchange capacity. - High-speed transport; the branched structure generates high mechanical strength, greatly reducing the water absorption and swelling rate of the anion exchange membrane, thereby improving dimensional stability; at the same time, the highly stable cationic groups and nucleophilic azurite groups increase its basic stability, and its high OH... - The conductivity, alkalinity stability, and high mechanical strength indicate that the polyazine sulfide anion exchange membrane prepared in this application can be used as anion exchange membrane material for alkaline fuel cells and alkaline electrolyzers.

[0061] In specific embodiments, R1 in this application is preferably one of the following structures:

[0062]

[0063] Where n is an integer greater than or equal to 0.

[0064] In a specific embodiment, R2 in this application is preferably one of the following structures:

[0065]

[0066]

[0067]

[0068]

[0069] Secondly, embodiments of this application provide a method for preparing the polyazine sulfide anion exchange membrane described in the first aspect, the method comprising:

[0070] (1) Preparation of polyazine sulfide precursor:

[0071] Na2S, azulene monomer A as shown in Formula 1, and branched monomer R2-Br were placed in a reaction vessel, dissolved in a first organic solvent, and the mixture was rapidly heated to carry out the reaction. The solid product was then washed, dried, and collected. The product was then dissolved in a second organic solvent, potassium carbonate and iodomethane were added, and the mixture was reacted in the dark. Ethyl acetate was added, and the mixture was purified to collect the polyazine sulfide polymer.

[0072]

[0073] (2) Preparation of polyazine sulfide anion exchange membrane:

[0074] Dissolve the cationic polyazine sulfide in a third organic solvent and collect I. - Type I thin film, making the I - Ion exchange is performed on a thin film to obtain OH-. - After purification, the polyazine sulfide anion exchange membrane was collected.

[0075] It should be noted that the polyazine sulfide precursor in the embodiments of this application is prepared by the following method: first, azulene monomer, branched monomer and Na2S are placed in a reaction vessel in a certain proportion and dissolved in a first organic solvent to obtain a mixture. The mixture is then rapidly heated and reacted for a certain time. The resulting solid product is collected and washed and dried with deionized water and ethanol to obtain polyazine sulfide.

[0076] It should be noted that the collection of polyazine sulfide polymer in the embodiments of this application includes: filtering to obtain solid polymer, washing three times with deionized water, washing once with anhydrous ethanol, and vacuum drying.

[0077] This application does not specify particular drying conditions, as long as a product of constant weight is obtained. In the embodiments of this application, the drying temperature is preferably 80°C, and the drying time is preferably 24 hours.

[0078] It should be noted that in the embodiments of this application, the reaction was carried out at room temperature with stirring in the dark for 24 hours.

[0079] It should be noted that in the embodiments of this application, the N atom in the azulene monomer reacts with iodomethane to form a quaternary ammonium cation.

[0080] It should be noted that ethyl acetate in the embodiments of this application is a good solvent for iodomethane, which can dissolve unreacted monomers. At the same time, it is a poor solvent for polymers, causing the polymers to precipitate and thus purifying the polymers.

[0081] In a specific embodiment, the molar ratio of the azulene monomer to the branched monomer in this application embodiment is preferably 0-99:1.

[0082] When the molar ratio of azulene monomer to branched monomer is greater than 99:1, i.e. when the content of branched monomer is too low, the branched monomer has a weak effect on improving the performance of the anion exchange membrane.

[0083] In a specific embodiment, the molar ratio of the sum of the amounts of branched monomers and azulene monomers to the amount of Na2S added is preferably 1:0.9-1.2.

[0084] In a specific embodiment, the molar ratio of the sum of the amounts of branched monomers and azulene monomers to Na2S is preferably 1:0.9-1.5.

[0085] Specifically, when the molar ratio of the sum of the branched monomers and azulene monomers to Na2S is less than 1:1.2, the local polymerization rate will be too fast, resulting in an excessively wide molecular weight distribution; when the molar ratio of the sum of the branched monomers and azulene monomers to Na2S is greater than 1:0.9, the reaction yield and rate will decrease.

[0086] In specific embodiments, the first organic solvent in this application is preferably one of dimethyl sulfoxide, N-methylpyrrolidone, and N,N-dimethylformamide.

[0087] In this process, the first organic solvents serve to dissolve the reactants.

[0088] In specific embodiments, the second organic solvent in this application is preferably one of acetonitrile, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, and sulfolane.

[0089] These second organic solvents serve to dissolve the polymer.

[0090] Thirdly, embodiments of this application provide a polyazine sulfide anion exchange membrane as described in the first aspect, and the application of the polyazine sulfide anion exchange membrane prepared by the method described in the second aspect in the preparation of alkaline fuel cells and alkaline electrolyzers.

[0091] In a specific embodiment, the polyazine sulfide anion exchange membrane of this application is subjected to OH at 80°C. - The conductivity is preferably at least 100 mS / cm.

[0092] The technical methods of this application will be further described below with reference to specific embodiments.

[0093] Example 1

[0094] This embodiment 1 provides a method for preparing a 6-6'-biazine crosslinked poly6-piperidinazium sulfide anion exchange membrane, namely a b-PAS-6Pip-BiAz anion exchange membrane, the specific steps of which are as follows:

[0095] (1) Monomers 6-(N-piperidine)-1,3-dibromoazine and 1,3,1',3'-tetrabromo-6,6'-azine were prepared according to the methods in the literature (Journal of Organic Chemistry 2019,84(3),1257-1275; Tetrabromo-6,6'-azine).

[0096] Weigh anhydrous Na₂S (245 mg), 6-(N-piperidine)-1,3-dibromoazine (1 g), 1,3,1',3'-tetrabromo-6,6'-azine (81 mg), and NaOH (20 mg) and place them in a reaction vessel. Add 20 mL of N-methylpyrrolidone (NMP). Rapidly heat to 200 °C and react for 6 h. After natural cooling, wash with deionized water and anhydrous ethanol. Filter and dry the product under vacuum at 80 °C for 8 h. The dried product is a black solid powder, totaling 0.7 g, with a yield of 94%. Dissolve 1 g of this product in 30 mL of dimethyl sulfoxide (DMSO), then add K₂CO₃ (0.39 g) and iodomethane (1 mL), and stir at room temperature in the dark for 24 h. Add 100 mL of ethyl acetate to the resulting viscous solution. The pale yellow precipitate was filtered, washed three times with water, and vacuum dried in an oven at 80°C for 24 hours to obtain b-PAS-6Pip-BiAz. The chemical structure of the polymer was determined by NMR and IR characterization. Figure 1 As shown, the weight-average molecular weight is 7.3 × 10⁻⁶. 5 , where a is an integer from 0 to 10000, b is an integer from 0 to 200, and ab corresponds to the random polymerization of the groups in parentheses.

[0097] To facilitate understanding of the synthesis process of the above-mentioned 6-6'-biazine crosslinked poly6-piperidinazium sulfide (b-PAS-6Pip-BiAz), this application provides a synthetic route diagram of 6-6'-biazine crosslinked poly6-piperidinazium sulfide (b-PAS-6Pip-BiAz), as follows: Figure 1 As shown, Figure 1 Synthetic pathway diagram of 6-6'-biazine crosslinked poly-6-piperidinazium sulfide (b-PAS-6Pip-BiAz) provided in this application.

[0098] (2) Preparation of poly6-piperidinium sulfide anion exchange membrane:

[0099] 1 g of b-PAS-6Pip-BiAz was dissolved in 30 mL of DMSO. The polymer solution was filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane, and the permeate was cast onto a clean glass plate. The solution was then evaporated at 80 °C for 12 h, then at 120 °C for 12 h, and finally vacuum dried at 120 °C for 24 h to completely remove residual solvent. A dense type I membrane was obtained by peeling it off from the glass plate. Ion exchange was performed in 1 M KCl solution at 80 °C for 12 h, followed by washing three times with deionized water to remove residual salt, yielding Cl... - A membrane of this type was prepared. Ion exchange was performed by incubating the membrane in 1M KOH solution at 80°C for 12 hours, followed by washing three times with deionized water under a nitrogen atmosphere to obtain OH⁻. - The membrane is a b-PAS-6Pip-BiAz anion exchange membrane.

[0100] Example 2

[0101] This embodiment 2 provides a method for preparing a polyazine sulfide anion exchange membrane, specifically a triazine-crosslinked poly6-piperidineazine sulfide (b-PAS-6pip-3AzPh) anion exchange membrane. The specific steps are as follows:

[0102] (1) Monomers 6-(N-piperidine)-1,3-dibromoazine and 1,3,5-tris(2-azine)benzene were prepared according to the methods described in the literature (Journal of Organic Chemistry 2019, 84(3), 1257-1275; Tetrahedron 2004, 60(25), 5357-5366). Anhydrous Na2S (232 mg), 6-(N-piperidine)-1,3-dibromoazine (1 g), 1,3,5-tris(2-azine)benzene (99 mg), and NaOH (20 mg) were weighed and placed in a reaction vessel, and 20 mL of N-methylpyrrolidone (NMP) was added. The temperature was rapidly raised to 200 °C and the reaction was carried out for 6 h. After natural cooling, the product was washed with deionized water and anhydrous ethanol. The filtered product was dried under vacuum at 80 °C for 8 h. The dried product was a black solid powder, totaling 0.7 g, with a yield of 95%. 1 g of this product was dissolved in 30 mL of dimethyl sulfoxide (DMSO), followed by the addition of K₂CO₃ (0.39 g) and methyl iodide (1 mL). The mixture was stirred at room temperature in the dark for 24 h. Ethyl acetate was added to the resulting viscous solution. The pale yellow precipitate was filtered, washed three times with water, and dried under vacuum in an oven at 80 °C for 24 h to obtain PAS-6pip. The chemical structure of the polymer was determined by NMR, IR, and UV characterization. Figure 2 As shown, the weight-average molecular weight is 7.5 × 10⁻⁶. 5 , where a is an integer from 0 to 10000, b is an integer from 0 to 200, and ab corresponds to the random polymerization of the groups in parentheses.

[0103] To facilitate understanding of the synthesis process of the above-mentioned triazine crosslinked poly(6-piperidinylazine) sulfide (b-PAS-6pip-3AzPh), this application provides a synthetic route diagram of triazine crosslinked poly(6-piperidinylazine) sulfide (b-PAS-6pip-3AzPh), as shown below. Figure 2 As shown, Figure 2 Synthetic pathway diagram for triazine crosslinked poly(6-piperidinazine sulfide) (b-PAS-6pip-3AzPh) provided in this application.

[0104] (2) Preparation of triazine crosslinked poly(6-piperidineazine sulfide) anion exchange membrane:

[0105] 1 g of b-PAS-6pip-3AzPh was dissolved in 30 mL of DMSO. The polymer solution was filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane, and the permeate was cast onto a clean glass plate. The solution was then evaporated at 80 °C for 12 h, then at 120 °C for 12 h, and finally vacuum dried at 120 °C for 24 h to completely remove residual solvent. A dense type I membrane was obtained by peeling it off from the glass plate. Ion exchange was performed in 1 M KCl solution at 80 °C for 12 h, followed by washing three times with deionized water to remove residual salt, yielding Cl... - A membrane of this type was prepared. Ion exchange was performed by incubating the membrane in 1M KOH solution at 80°C for 12 hours, followed by washing three times with deionized water under a nitrogen atmosphere to obtain OH⁻. - The membrane type is b-PAS-6pip-3AzPh anion exchange membrane.

[0106] Example 3

[0107] This embodiment 3 provides a method for preparing a polyazulene sulfide anion exchange membrane, namely a poly6-piperidinium azulene sulfide (PAS-6pip) anion exchange membrane, the specific steps of which are as follows:

[0108] (1) The monomer 6-(N-piperidine)-1,3-dibromoazine was prepared according to the literature method (Journal of Organic Chemistry 2019, 84(3), 1257-1275). Anhydrous Na2S (232 mg), 6-(N-piperidine)-1,3-dibromoazine (1 g), and NaOH (20 mg) were weighed and placed in a reaction vessel, and 20 mL of N-methylpyrrolidone (NMP) was added. The temperature was rapidly raised to 200 °C and the reaction was carried out for 6 h. After natural cooling, the product was washed with deionized water and anhydrous ethanol. The filtered product was dried under vacuum at 80 °C for 8 h. The dried product was a black solid powder, with a total weight of 0.7 g and a yield of 95%. 1 g of the product was dissolved in 30 mL of dimethyl sulfoxide (DMSO), and then K2CO3 (0.39 g) and iodomethane (1 mL) were added. The mixture was stirred at room temperature in the dark for 24 h. Ethyl acetate was added to the resulting viscous solution. The pale yellow precipitate was filtered, washed three times with water, and vacuum dried in an oven at 80°C for 24 hours to obtain PAS-6pip. The chemical structure of the polymer was determined by NMR and IR characterization. Figure 3 As shown, the weight-average molecular weight is 6.8 × 10⁻⁶. 5 , where a is an integer from 0 to 10000, b is an integer from 0 to 200, and ab corresponds to the random polymerization of the groups in parentheses.

[0109] To facilitate understanding of the synthesis process of poly(6-piperidinylazine sulfide) (PAS-6pip), this application provides a synthetic route diagram for poly(6-piperidinylazine sulfide) (PAS-6pip), as follows: Figure 3 As shown, Figure 3 Synthetic pathway diagram for poly(6-piperidinylazine sulfide) (PAS-6pip) provided in this application.

[0110] (2) Preparation of poly6-piperidinium sulfide anion exchange membrane:

[0111] PAS-6pip (1 g) was dissolved in 30 mL of DMSO. The polymer solution was filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane, and the permeate was cast onto a clean glass plate. The solution was then evaporated at 80 °C for 12 h, then at 120 °C for 12 h, and finally vacuum dried at 120 °C for 24 h to completely remove residual solvent. A dense type I membrane was obtained by peeling it off from the glass plate. Ion exchange was performed in 1 M KCl solution at 80 °C for 12 h, followed by washing three times with deionized water to remove residual salt, yielding Cl... - A membrane of this type was prepared. Ion exchange was performed by incubating the membrane in 1M KOH solution at 80°C for 12 hours, followed by washing three times with deionized water under a nitrogen atmosphere to obtain OH⁻. - The type of membrane is the PAS-6pip anion exchange membrane.

[0112] To verify the performance of the polyazine sulfide anion exchange membranes prepared in Examples 1-3, performance tests were conducted on the polyazine sulfide anion exchange membranes and the commercial FAA3-50 anion exchange membranes. The test results are shown in the figure.

[0113] Tests showed that the b-PAS-6Pip-BiAz anion exchange membrane prepared in Example 1 had a thickness of 50±5 micrometers and an OH content of 80°C. - The conductivity is 155 mS / cm, its ion exchange capacity is 2.4 mmol / g, its swelling ratio is 35%, its tensile strength is 68 MPa, its elongation at break is 13%, and it maintains alkaline stability for 1000 h at 80 °C and 1 M KOH. The b-PAS-6pip-3AzPh anion exchange membrane prepared in Example 2 has a thickness of 50 ± 5 μm and maintains alkaline stability for 1000 h at 80 °C and 1 M KOH. - The conductivity is 150 mS / cm, its ion exchange capacity is 2.4 mmol / g, its swelling ratio is 46%, its tensile strength is 60 MPa, its elongation at break is 13%, and it maintains alkaline stability for 1000 h at 80 °C in 1 M KOH. Meanwhile, the PAS-6pip anion exchange membrane prepared in Example 3 has a thickness of 50 ± 5 μm and maintains alkaline stability for 1000 h at 80 °C in 1 M KOH. - The conductivity is 144 mS / cm, the ion exchange capacity is 2.4 mmol / g, the swelling ratio is 55%, the tensile strength is 43 MPa, the elongation at break is 12%, and it maintains alkaline stability in 1M KOH at 80℃ for 1000 h. This indicates that the homogeneous anion exchange membrane prepared in this example has minimal swelling, suitable ion conductivity and anion exchange capacity, and good mechanical properties. Furthermore, with the addition of branched monomers, the OH... - Increased electrical conductivity, decreased swelling ratio, and enhanced mechanical properties. Furthermore, the polyazine sulfide anion exchange membrane prepared in the examples outperformed the commercial FAA3-50 anion exchange membrane in both electrical conductivity and water electrolysis performance.

[0114] Figure 4 The polyazine sulfide anion exchange membranes prepared in Examples 1, 2, and 3 (OH) - Conductivity test results. Figure 5 The results of water electrolysis tests on the polyazine sulfide anion exchange membranes prepared in Examples 1, 2 and 3 are shown.

[0115] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A polyazine sulfide anion exchange membrane, characterized in that, The polyazine sulfide anion exchange membrane contains a polyazine sulfide polymer, and the polyazine sulfide polymer has at least one or more of the following structures: ; ; ;or ; Wherein, R1 is a cationic group, R2 is a branched group, a is any integer between 1 and 10000, and b is any integer between 0 and 10000; R1 is each individually one or more of the following structures: 、 、 、 、 、 、 、 ， Where n is any integer between 1 and 100; R2 is each individually one or more of the following structures: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 ； In the above structure, the wavy line "﹏" represents the connection point.

2. The ion exchange membrane according to claim 1, characterized in that, Membrane thickness 10-200μm, The polymerization mode of the groups in parentheses corresponding to a and b is random polymerization.

3. A method for preparing the polyazine sulfide anion exchange membrane according to any one of claims 1-2, characterized in that, include: (1) Preparation of polyazine sulfide polymer: Na2S, azulene monomer A as shown in Formula 1, and branched monomer R2-Br were placed in a reaction vessel, dissolved in a first organic solvent, heated, and reacted. The solid product was then washed, dried, and collected. The product was dissolved in a second organic solvent, potassium carbonate and iodomethane were added, and the reaction was carried out in the dark. Ethyl acetate was added, and the mixture was purified and the polyazine sulfide polymer was collected. ； Formula 1 Azulene monomer A structure The specific structures of R1 and R2 are the same as the corresponding R1 and R2 group structures in claim 1, and are one or more of the corresponding R1 and R2 group structures in claim 1; (2) Preparation of polyazine sulfide anion exchange membrane: The polyazine sulfide polymer is dissolved in a second organic solvent to form a film, which is then dried and collected. - Type I thin film, making the I - Ion exchange is performed on a thin film to obtain OH-. - A type of membrane for collecting polyazine sulfide anion exchange membranes.

4. The method for preparing the polyazine sulfide anion exchange membrane according to claim 3, characterized in that, In step (1), the molar ratio of the sum of the amounts of azulene monomer and the branched monomer to the amount of Na2S is 1:0.9-1.5, and the molar ratio of the amounts of the branched monomer and the azulene monomer is 0-1:

1.

5. The method for preparing the polyazine sulfide anion exchange membrane according to claim 4, characterized in that, In step (1), the molar ratio of the sum of the amounts of azulene monomer and the branched monomer to the amount of Na2S is 1:0.9-1.2, and the molar ratio of the amounts of the branched monomer and the azulene monomer is 0.05-0.5:

1.

6. The method for preparing the polyazine sulfide anion exchange membrane according to claim 3, characterized in that, The reaction temperature is greater than 150°C and the reaction time is greater than 4 hours.

7. The method for preparing the polyazine sulfide anion exchange membrane according to claim 6, characterized in that, The reaction temperature is 150-220℃, and the reaction time is 4-24 hours.

8. The method for preparing the polyazine sulfide anion exchange membrane according to claim 3, characterized in that, The first organic solvent is one or more of dimethyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide, and the concentration of Na2S in the first organic solvent is 0.1-2 mol / L.

9. The method for preparing the polyazine sulfide anion exchange membrane according to claim 3, characterized in that, The second organic solvent is one or more of acetonitrile, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide and sulfolane; In step (1), the concentration of the product in the second organic solvent is 0.1-1 g / mL, the final concentration of potassium carbonate is 1 mol / L, and the final concentration of iodomethane is 1 g / mL.

10. The application of a polyazine sulfide anion exchange membrane according to any one of claims 1-2, or a polyazine sulfide anion exchange membrane prepared by any one of claims 3-9, as a separator in an alkaline fuel cell or an alkaline electrolyzer.

11. The application according to claim 10, characterized in that, The polyazine sulfide anion exchange membrane at 80 °C has OH... - The conductivity is at least 100 mS / cm.

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