Aryl quinuclidinium anion exchange membrane containing conjugated twisted structure and preparation method of aryl quinuclidinium anion exchange membrane

Abstract

The invention discloses an aryl quinine onium anion exchange membrane containing a conjugated twisted structure, and also discloses a preparation method of the anion exchange membrane, and the preparation method comprises the following steps: mixing Ar1, Ar2 and 3-quinuclidinone hydrochloride, dissolving in a solvent I, adding a catalyst I and a catalyst II, and reacting to obtain an aryl quinine precursor polymer; dissolving the precursor polymer in a solvent III, adding a catalyst III and a nucleophilic reagent I, and carrying out quaternization reaction to prepare an aryl quinine onium polymer; dissolving the aryl quinine onium polymer in a solvent III, and filtering to obtain a membrane casting solution; and carrying out tape casting and drying on the membrane casting solution, and then carrying out ion exchange to obtain the anion exchange membrane containing the conjugated twisted structure. The anion exchange membrane has the characteristics of high mechanical strength, high conductivity and good alkali-resistant stability. According to the method, the stability and the ionic conductivity of the anion exchange membrane are improved by introducing a conjugate distortion structure, and the method is simple and convenient to operate and easy for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, specifically relating to an arylquinine-onium anion exchange membrane with a conjugated twisted structure, and also to a method for preparing the anion exchange membrane. Background Technology

[0002] Anion exchange membranes (AEMs) are a type of membrane that can selectively conduct anions (such as OH-). - Cl - High-molecular functional membrane materials (such as alkaline membrane fuel cells, water electrolysis hydrogen production devices, and electrodialysis desalination systems) are core components of advanced electrochemical equipment. Their performance directly determines the energy conversion efficiency, long-term stability, and industrial application potential of the equipment. Therefore, they have an irreplaceable position in the fields of energy storage and conversion, environmental water treatment, etc.

[0003] In recent years, with the surge in global demand for clean energy and green chemical technologies, the development of AEMs has become a research hotspot in the interdisciplinary field of polymer materials and electrochemistry. Current mainstream AEMs design approaches largely revolve around a structure of "polymer backbone + cationic functional side chains." The chemical stability and mechanical strength of the backbone, along with the ion conductivity and alkali resistance of the side chains, are key factors determining the overall performance of AEMs. Existing technologies still struggle to simultaneously achieve synergistic optimization of "high stability, high conductivity, and excellent mechanical properties," presenting a significant technological bottleneck.

[0004] On the one hand, traditional non-conjugated backbone AEMs (such as polyolefin, polyether, and polyvinyl chloride AEMs) have the advantages of low synthesis cost and ease of operation, but their backbones lack electron delocalization structures and are easily affected by OH groups in alkaline environments (especially high-temperature, high-concentration alkaline solutions). - The attack causes the main chain to hydrolyze and break down. Simultaneously, traditional non-conjugated main chains typically employ the introduction of flexible side chains to increase ion exchange capacity (IEC), thereby improving the membrane's ionic conductivity. However, if the membrane is too flexible, it is prone to excessive swelling after water absorption, leading to a sharp drop in the membrane's mechanical strength. This is the trade-off effect between ionic conductivity and IEC in anion exchange membranes. Currently, researchers in the field generally agree that this trade-off effect is a major factor restricting the development of anion exchange membranes.

[0005] On the other hand, while existing conjugated backbone-type AEMs improve the alkali resistance of the backbone through the electronic delocalization effect of the conjugated structure and enhance mechanical properties through π-π stacking, some conjugated backbones are too hydrophobic, making it difficult to form continuous and regular hydrophilic ion channels, leading to OH... - Its conductivity is too low to meet the requirements of high-power electrochemical devices.

[0006] In addition, in terms of the selection of cation side groups, existing AEMs mostly use traditional quaternary ammonium salts (such as trimethylammonium), which have poor alkali resistance. Although some studies have tried to introduce heterocyclic cations such as imidazolium and pyridinium, these cations have insufficient compatibility with the conjugated backbone, which can easily lead to excessive phase separation in the membrane, thus reducing mechanical properties. Moreover, there is still room for improvement in the alkali resistance of these heterocyclic cations. Summary of the Invention

[0007] The purpose of this invention is to provide an arylquinonium anion exchange membrane with a conjugated twisted structure, which has the characteristics of high mechanical strength, high ion conductivity and good alkali resistance.

[0008] Another objective of this invention is to provide a method for preparing the above-mentioned anion exchange membrane, which improves the stability and ion conductivity of the anion exchange membrane by introducing a conjugate twisted structure, and is simple to operate and easy to industrialize.

[0009] The technical solution adopted in this invention is: An arylquinonium anion exchange membrane containing a conjugated twisted structure is prepared from an arylquinonium polymer containing a conjugated twisted structure, wherein the arylquinonium polymer containing the conjugated twisted structure comprises the structural unit shown in formula (I):

[0010] (I) Where x represents the proportion of Ar1 unit in the total Ar1 and Ar2, and x is a decimal between 0 and 1; X represents the anion type, including I, Br, Cl, OH, and HCO3.

[0011] The invention is further characterized by: Ar1 is selected from one of the following structural segments: .

[0012] Ar2 is selected from one of the following structural segments: .

[0013] Arylquinonium polymers containing conjugated twisted structures are selected from one of the following structural formulas: .

[0014] Another technical solution adopted in this invention is: A method for preparing arylquinonium anion exchange membranes containing conjugated twisted structures includes: Step 1: Ar1, Ar2 and 3-quinine cyclic ketone hydrochloride are mixed and dissolved in solvent I, and catalyst I and catalyst II are added to react and obtain arylquinine precursor polymer; Step 2: Dissolve the precursor polymer in solvent III, add catalyst III and nucleophile I to carry out quaternization reaction to obtain arylquinonium polymer; Step 3: Dissolve the arylquinonium polymer in solvent III, filter, and obtain the casting solution; Step 4: Cast the casting solution, dry it, and then perform ion exchange to obtain an anion exchange membrane with a conjugated twisted structure.

[0015] Another feature of the technical solution of the present invention is that: Step 1 is as follows: Ar1 and Ar2 were mixed and added to solvent I. After dissolving evenly in an ice bath, 3-quinine cyclic ketone hydrochloride was added and stirred for 5-15 min. Then, catalyst I and catalyst II were slowly added and stirred continuously in an ice bath for 10-30 min. After removing the ice bath, the system was placed at room temperature for 24-48 h to react. Solvent I was added to dilute the system, and the diluted solution was added dropwise to solvent II for quenching. The solution was then filtered, washed, and dried to obtain an arylquinine precursor polymer containing a conjugated twisted structure.

[0016] Solvent I is one of hexane, pyrrolidone, petroleum ether, and dichloromethane; Solvent II is one or a mixture of methanol, ethanol, and deionized water; Catalyst I is one or a mixture of methanesulfonic acid and trifluoroacetic acid; Catalyst II is one or a combination of trifluoromethanesulfonic acid, trifluoroacetic acid, concentrated sulfuric acid, and concentrated nitric acid; The total concentration of Ar1 + Ar2 is 1~2 mol / L; The molar ratio of Ar1, Ar2, 3-quinine cycloketone hydrochloride, Catalyst I, and Catalyst II is 0.1~0.3:0.7~0.9:1~1.25:1~2:5~10.

[0017] Step 2 is as follows: The precursor polymer was dissolved in solvent III, catalyst III and nucleophile I were added, and the reaction was carried out at 25-35°C for 12-36 h. The reaction was quenched in solvent IV, and then filtered, washed and dried to obtain an arylquinonium polymer containing a conjugated twisted structure.

[0018] Solvent III is one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; catalyst III is one or a mixture of potassium carbonate, sodium carbonate, sodium bicarbonate, and sodium hydroxide; nucleophile I is one of iodomethane, bromomethane, and chloromethane; solvent IV is one of diethyl ether, ethyl acetate, and deionized water; the molar ratio of the precursor polymer, catalyst III, and nucleophile I is 1:2~5:2~5.

[0019] In step 3, the arylquinonium polymer is dissolved in solvent III and filtered through a 5 μm needle filter to obtain a casting solution, wherein solvent III is dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone. In step 4, the casting solution is cast onto a glass plate with a pre-set area. After drying, the resulting polymer film is immersed in a salt solution for ion exchange to obtain an arylquinonium polymer film containing a conjugated twisted structure.

[0020] The beneficial effects of this invention are: (1) The quinine-onium cations in the anion exchange membrane of the present invention have a rigid heterocyclic structure and strong electron delocalization ability, which can reduce OH- - Nucleophilic attack; at the same time, since the quinineonium cation has fewer β-H, it can significantly inhibit the Hofmann elimination reaction, thus greatly improving the alkali resistance stability of the anion exchange membrane; (2) In the arylquinonium anion exchange membrane structure containing a conjugated twisted structure prepared in this invention, the main chain formed by alternating connections of conjugated and non-conjugated units is strongly hydrophobic, while the quinonium cation side groups are hydrophilic. A regular microphase separation structure is constructed through the binary structure of "hydrophobic conjugated main chain - hydrophilic ionic side groups", which is OH - The transmission provides a continuous channel, which is beneficial for improving ion conductivity; (3) The arylquinine onion anion exchange membrane with conjugated twisted structure prepared by the method of the present invention enhances the π-π stacking effect due to the introduction of conjugated monomers, thereby improving the mechanical stability of the membrane; at the same time, in the presence of the twisted structure, a larger free volume is formed in the membrane, so the water absorption rate and IEC can be improved while maintaining the mechanical strength of the membrane, thereby improving the ion conductivity and fuel cell performance. (4) The anion exchange membrane of the present invention breaks through the current technical bottleneck and achieves a synergistic improvement in ion conduction, mechanical properties, alkali resistance and antioxidant stability. The test results show that it has the following advantages: a. High ion conductivity, which can reach 248 mS / cm at 80℃. -1 a. Superior to conventional anion exchange membranes; b. Significantly improved alkali resistance; after immersion in 1M NaOH solution for 2000 hours, the membrane still maintains 92.9% of its initial conductivity, far exceeding traditional non-conjugated and conjugated anion exchange membranes; c. Excellent fuel cell performance; under conditions without back pressure, the peak power density can reach 774 mW / cm³. -2 Compared to existing anion exchange membranes, this invention exhibits superior fuel cell performance. Furthermore, the method described in this invention is simple to operate and easily scalable for industrial production. Therefore, this anion exchange membrane has significant application value in industries involving hydrogen energy, such as alkaline membrane fuel cells, water electrolysis for hydrogen production, flow batteries, and electrochemical ammonia synthesis. Attached Figure Description

[0021] Figure 1 The 1H NMR spectrum of the arylquinine precursor polymer (PPPTQ) with conjugated twisted structure prepared in Example 1 is shown below. Figure 2 The 1H NMR spectrum of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1; Figure 3 A digital photograph of the arylquinonium anion exchange membrane (QPPPTQ) with a conjugated twisted structure prepared in Example 1; Figure 4 This is a high-resolution scanning electron microscope image of the arylquinonium anion exchange membrane (QPPPTQ) with a conjugated twisted structure prepared in Example 1; Figure 5 An atomic force microscope image of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1; Figure 6 Small-angle X-ray scattering (SAXS) of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1; Figure 7 The stress-strain curve of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 is shown. Figure 8 The tensile strength and elongation at break of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 are shown in the figure. Figure 9 The thermogravimetric curve of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 is shown. Figure 10 The conductivity of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 at different temperatures; Figure 11 The Arrhenius curves of the conductivity of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 at different temperatures are shown. Figure 12 The remaining weight of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 after treatment in Fenton's reagent at 40°C for different times; Figure 13The conductivity change of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 after immersion in 1M NaOH solution at 80°C for 2000 h; Figure 14 The mechanical properties of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 after immersion in 1M NaOH solution at 80°C for 2000 h are shown. Figure 15 The polarization curve and peak power density curve of the arylquinonium anion exchange membrane (QPPPTQ) with conjugated twisted structure prepared in Example 1 were recorded in the H2-O2 battery test at 80°C. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0023] The arylquinonium anion exchange membrane with a conjugated twisted structure prepared in this invention is made from an arylquinonium polymer with a conjugated twisted structure, wherein the arylquinonium polymer with a conjugated twisted structure comprises the structural unit shown in formula (I):

[0024] (I) Where x represents the proportion of Ar1 unit in the total Ar1 and Ar2, and x is a decimal between 0 and 1; X represents the anion type, including I, Br, Cl, OH, and HCO3.

[0025] Ar1 is selected from one of the following structural segments:

[0026] Ar2 is selected from one of the following structural segments:

[0027] Preferably, Ar1 is selected from the following structures: or

[0028] Preferably, the arylquinonium polymer containing the conjugated twisted structure is selected from one of the following structural formulas:

[0029] Where X represents the type of anion, including I, Br, Cl, OH, and HCO3.

[0030] A method for preparing arylquinonium polymers containing conjugated twisted structures includes the following steps: Step 1: Ar1 and Ar2 were mixed and added to solvent I. After dissolving evenly in an ice bath, 3-quinine cycloketone hydrochloride was added and stirred for 5-15 min. Then, catalyst I and catalyst II were slowly added and stirred continuously in an ice bath for 10-30 min. After removing the ice bath, the system was placed at room temperature for 24-48 h. Solvent I was added to dilute the system, and the diluted solution was added dropwise to solvent II for quenching. The solution was then filtered, washed, and dried to obtain the arylquinine precursor polymer containing a conjugated twisted structure (hereinafter referred to as the precursor polymer). Solvent I is one of hexane, pyrrolidone, petroleum ether, and dichloromethane; solvent II is one or a mixture of methanol, ethanol, and deionized water; catalyst I is one or a mixture of methanesulfonic acid and trifluoroacetic acid; catalyst II is one or a combination of trifluoromethanesulfonic acid, trifluoroacetic acid, concentrated sulfuric acid, and concentrated nitric acid; the total concentration of (Ar1+Ar2) is 1~2 mol / L; the molar ratio of Ar1, Ar2, 3-quinine cycloketone hydrochloride, catalyst I, and catalyst II is 0.1~0.3:0.7~0.9:1~1.25:1~2:5~10.

[0031] Step 2: Dissolve the precursor polymer in solvent III, add catalyst III and nucleophile I to carry out quaternization reaction. After the reaction is carried out at 25~35℃ for 12~36h, it is quenched in solvent IV, then filtered, washed and dried to obtain arylquinonium polymer containing conjugated twisted structure.

[0032] Solvent III is one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); catalyst III is one or a mixture of potassium carbonate, sodium carbonate, sodium bicarbonate, and sodium hydroxide; nucleophile I is one of iodomethane, bromomethane, and chloromethane; solvent IV is one of diethyl ether, ethyl acetate, and deionized water; and the molar ratio of the precursor polymer, catalyst III, and nucleophile I is 1:2~5:2~5.

[0033] The reaction equation for arylquinonium polymers containing conjugated twisted structures is as follows:

[0034] X1 is one of I, Br, or Cl, depending on the type of nucleophile I.

[0035] The present invention discloses a method for preparing an arylquinonium anion exchange membrane containing a conjugated twisted structure, comprising the following steps: Step 1: Dissolve the arylquinonium polymer containing the conjugated twisted structure in solvent III and filter it through a 5 μm needle filter to obtain the casting solution; Step 2: Cast the casting solution obtained in Step 1 onto a glass plate with a pre-set area, and after drying, obtain an arylquinonium polymer film containing a conjugated twisted structure; Step 3: Immerse the polymer film obtained in Step 2 in a salt solution for ion exchange to obtain an arylquinonium anion exchange membrane with a conjugated twisted structure that can be used in electrochemical devices.

[0036] The types of salt solutions include, but are not limited to, NaCl solution, NaBr solution, NaOH solution, and NaHCO3 solution.

[0037] The reaction equation is as follows:

[0038] X is one of I, Br, Cl, OH, and HCO3, depending on the type of salt solution.

[0039] The arylquinine-onium anion exchange membrane containing a conjugated twisted structure of the present invention can be applied in alkaline fuel cells, water electrolysis for hydrogen production, CO2 reduction, electrochemical ammonia synthesis, or flow batteries.

[0040] Example 1: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.28 g phenanthrene and 3.32 g p-terphenyl, and dissolve them in 10 mL n-hexane to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 2.58 g 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 5 min, slowly add 1.21 mL trifluoroacetic acid and 7.2 mL trifluoromethanesulfonic acid; after continuing the reaction in the ice bath for 10 min, remove the ice bath, and place the system at room temperature for 24 h to obtain solution B; add n-hexane to solution B to dilute it; add the diluted solution B dropwise to deionized water to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[phenanthrene-co-p-terphenylquinine ring] (PPPTQ).

[0041] Step 2: Weigh 0.5g of PPPTQ and dissolve it in 7.5mL of DMSO. Stir until the solution is clear and transparent to obtain solution C. Add 0.41g of potassium carbonate and 0.43g of iodomethane to solution C to carry out a quaternization reaction. After reacting at 25℃ for 12h, solution D is obtained. Add diethyl ether dropwise to solution D to precipitate the solid. After filtration and drying, a pale yellow solid is obtained, which is the iodide-form poly[phenanthrene-co-p-terphenylquinineonium] (QPPPTQ).

[0042] Step 3: Dissolve QPPPTQ in DMSO to obtain a clear and transparent solution E. Pour solution E onto a glass plate of pre-set area and dry it in an oven to obtain the QPPPTQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPPTQ membrane in this form is stored in deionized water for subsequent testing.

[0043] The following performance tests were performed on the arylquinine precursor polymer and the arylquinine onion anion exchange membrane prepared in this embodiment: Figure 1 The 1H NMR spectrum of the poly[phenanthrene-co-p-terphenylquinine ring] precursor polymer (PPPTQ) prepared in Example 1 is shown. Figure 1 The chemical shifts of the protons in PPPTQ in DMSO-d6 were 8.3-7.8 ppm, 7.5-7.8 ppm, 4.31 ppm, 3.54 ppm, 3.22 ppm and 3.13 ppm, 1.96 ppm and 1.79 ppm, respectively, corresponding to protons 1-4 of the phenanthrene unit in the PPPTQ polymer, protons 9-11 on the p-terphenyl ring, and protons 8, 5, 7, and 6 on the quinine ring, with an area ratio of 0.8:10.8:2:1:4:4, consistent with the theoretical results. Protons 7 and 6 each showed two small peaks due to the presence of two methylene protons with different chemical environments. Analysis of the 1H NMR spectrum of the PPPTQ polymer confirmed that the method of this invention successfully prepared the poly[phenanthrene-co-p-terphenylquinine ring] precursor polymer PPPTQ.

[0044] Figure 2 The 1H NMR spectrum of the poly[phenanthrene-co-p-terphenylquinineonium] (QPPPTQ) polymer in the iodine ion form prepared in Example 1. Figure 2The chemical shifts of protons in QPPPTQ in DMSO-d6 were 8.3-7.8 ppm, 7.5-7.8 ppm, 4.48 ppm, 3.56 ppm, 3.43 ppm and 3.30 ppm, 3.17 ppm, 2.04 ppm and 1.84 ppm, respectively, similar to the PPPTQ precursor polymer. These chemical shifts correspond to protons 1-4 of the phenanthrene unit in the QPPPTQ polymer, protons 9-11 on the terphenyl, and protons 8, 5, 7, 9, and 6 on the quinine ring, with an area ratio of 0.8:10.8:2:1:4:3:4, consistent with theoretical results. The proton peak at position 9 is attributed to the methyl group, and its chemical shift is lower in the field, indicating that the methyl group from iodomethane was successfully introduced onto the N atom of PPPTQ, demonstrating the successful quaternization reaction. Analysis of the proton NMR spectrum of the QPPPTQ polymer demonstrates that the method of this invention successfully prepared poly[phenanthrene-co-p-terphenylquinineonium] (QPPPTQ) polymer in the form of iodide ions.

[0045] Figure 3 The image shows a digital photograph of the QPPPTQ anion exchange membrane prepared in Example 1. It can be seen that this example yielded a membrane with a size of 9.5 mm. 7.5cm 2 The film is transparent and smooth, with no pores or defects on its surface.

[0046] Figure 4 This is a high-resolution scanning electron microscope (SEM) image of the QPPPTQ anion exchange membrane prepared in Example 1. Figure 4 SEM analysis of the surface morphology of the membrane revealed that the membrane surface exhibits a uniform and dense state, free of pores or defects, which is a prerequisite for the application of anion exchange membranes in electrochemical devices.

[0047] The alternating arrangement of hydrophobic backbones and hydrophilic cationic groups in anion exchange membranes creates a microphase separation structure, which facilitates the formation of interconnected and ordered ion transport channels. The hydrophilic-hydrophobic microphase separation structure of anion exchange membranes can be further analyzed and characterized using atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS).

[0048] Figure 5 The image shows an atomic force microscope (AFM) image of the QPPPTQ anion exchange membrane prepared in Example 1, including a height diagram (left) and a phase diagram (right). Figure 5AFM analysis was performed, and the microstructure of the anion exchange membrane was observed by examining the height and phase diagrams. The height diagram revealed numerous granular structures with heights ranging from -5.6 nm to 6.8 nm, indicating a relatively smooth surface on the microscopic level. The phase diagram showed a distinct distribution of dark and light phases, with darker areas representing hydrophilic regions and lighter areas representing hydrophobic regions, indicating a clear microphase separation structure in the anion exchange membrane.

[0049] Figure 6 This is a small-angle X-ray scattering (SAXS) pattern of the QPPPTQ anion exchange membrane prepared in Example 1. Figure 6 As shown, the QPPPTQ film exhibits a distinct scattering peak at a position of 13.116 nm. -1 This indicates the presence of a microphase separation structure formed by ion cluster aggregation in the QPPPTQ membrane. According to Bragg's formula d = 2π / q... max The inter-domain spacing of ion clusters in the QPPPTQ membrane can be calculated to be 0.48 nm. This spacing indicates that the ion clusters are in a tight and orderly aggregated state within the membrane, without obvious uneven dispersion or excessive aggregation. This result is consistent with the AFM results.

[0050] Analysis of AFM and SAXS results shows that the QPPPTQ membrane exhibits a good microphase separation structure. This excellent microphase separation structure is primarily determined by the difference in chain arrangement between the hydrophobic rigid conjugated backbone and the hydrophilic cationic groups: the rigid and conjugated backbone structure forms hydrophobic segments, while the cationic groups effectively aggregate to form hydrophilic segments, creating ion clusters and ultimately resulting in a distinct microphase separation structure.

[0051] Anion exchange membranes need to maintain good mechanical properties during use, otherwise it will affect the service life of the device. Figure 7 The image shows the stress-strain curve of the QPPPTQ anion exchange membrane prepared in Example 1. Figure 8 The diagram shows the tensile strength and elongation at break of the QPPPTQ anion exchange membrane prepared in Example 1. Figure 7 , 8 As shown, the tensile strength and elongation at break of the QPPPTQ membrane are 29.17 MPa and 29%, respectively, indicating that the uniform distribution and good compatibility of the rigid main chain structure and flexible cationic group structure in the QPPPTQ membrane enable the anion exchange membrane to achieve good mechanical properties.

[0052] Because anion exchange membranes operate at high temperatures (60-100℃) in the hydrogen energy field, the thermal stability of AEMs should be a key focus during long-term use. Figure 9The thermogravimetric analysis (TGA) curves of the PPPTQ precursor polymer and the QPPPTQ polymer film prepared in Example 1 show that the mass loss of both the PPPTQ polymer and the QPPPTQ film between 0-100℃ mainly comes from the evaporation of bound water and residual solvent within the film. PPPTQ exhibits two degradation stages: 410℃-517℃ is the degradation stage of quinine cyclic amines, and 517℃-645℃ is the degradation stage of terphenyl and phenanthrene in the main chain. QPPPTQ, on the other hand, has three degradation stages: the first stage (256℃-395℃) is the degradation process of cationic groups; the second stage (395℃-492℃) is the degradation process of quinine cyclic amines; and the third stage (492℃-637℃) is the degradation process of terphenyl and phenanthrene in the main chain. Compared to PPPTQ, QPPPTQ reaches its maximum degradation rate in the first stage at a lower temperature—355℃—due to the presence of quaternary ammonium cations, which lowers the initial degradation temperature. However, regardless of whether it is PPPTQ or QPPPTQ, the initial degradation temperature is above 200℃, which is much higher than the actual operating temperature of anion exchange membranes, indicating that the prepared QPPPTQ membrane has good thermal stability.

[0053] Figure 10 The OH groups of the QPPPTQ anion exchange membrane prepared in Example 1 at different temperatures - The conductivity can be seen from the OH groups of the QPPPTQ membrane. - The conductivity increases with increasing temperature, reaching a maximum of 248 mS / cm at 80℃. -1 Therefore, it can be seen that the QPPPTQ anion exchange membrane has good ion conduction performance.

[0054] Figure 11 The QPPPTQ anion exchange membrane prepared in Example 1 was tested for OH- at different temperatures. - The Arrhenius curve at conductivity can illustrate the microscopic mechanism of ion transport in anion exchange membranes. For example... Figure 11 As shown, the Arrhenius curve of the QPPPTQ membrane exhibits a good linear relationship, and the ion transport activation energy Ea = 14.34 kJ can be calculated from the slope and intercept. mol -1 This indicates that the QPPPTQ membrane has low transport resistance, which is beneficial for its application in practical electrochemical devices.

[0055] In anion exchange membrane fuel cells (AEMFCs), redox reactions continuously occur at the anode and cathode. During oxygen reduction (ORR) at the cathode, strong oxidizing intermediates such as hydrogen peroxide and hydroxyl radicals are inevitably generated. These substances can directly attack the chemical bonds in the membrane, gradually degrading its molecular structure. This leads to a decrease in the membrane's ion exchange capacity (IEC), a decline in its mechanical strength, and ultimately, the loss of its ion conduction and gas barrier functions. Therefore, anion exchange membranes need to possess good antioxidant stability. In the laboratory, a 3wt% H₂O₂ solution containing 4ppm FeSO₄ (Fenton's reagent) can be used to simulate the actual operating environment of an AEMFC. By immersing the membrane in Fenton's reagent for a certain period of time and measuring the remaining mass at different immersion times, the antioxidant stability of the AEM can be evaluated. Figure 12 The remaining mass of the QPPPTQ anion exchange membrane prepared in Example 1 after immersion in Fenton's reagent at 40°C for different times is shown. It can be seen that after 168 hours of oxidation test, the QPPPTQ membrane can retain 93.1% of its initial weight, which indicates that the QPPPTQ membrane has good antioxidant stability, and is therefore beneficial for practical application in AEMFC.

[0056] In AEMFC, OH - As charge carriers transporting substances within the membrane, anion exchange membranes must maintain stable structure and performance in a strongly alkaline environment. If their alkalinity resistance is insufficient, the cation exchange groups within the membrane will undergo Hoffmann elimination or nucleophilic substitution reactions under alkaline conditions, leading to group shedding, a sharp drop in ion exchange capacity (IEC), and direct blockage of OH-. - The transport channels are disrupted, causing the membrane to lose its ion-conducting ability. Therefore, anion exchange membranes need to possess a certain degree of alkali resistance. Specifically, an 80℃, 1M NaOH solution can be used to simulate the actual operating environment of an AEMFC. The anion exchange membrane is immersed in the solution, and the OH content is measured at different alkali immersion times. - The conductivity and mechanical properties after alkali soaking are used to evaluate the alkali resistance stability of the anion exchange membrane.

[0057] Figure 13 The conductivity change of the QPPPTQ anion exchange membrane prepared in Example 1 after immersion in 1M NaOH solution at 80°C for 2000 h. (The text then repeats the description of QPPPTQ's OH content.) - The conductivity, as shown in the alkali resistance test, can maintain 92.9% of its initial value.

[0058] Figure 14The mechanical properties of the QPPPTQ anion exchange membrane prepared in Example 1 after immersion in 1M NaOH solution at 80℃ for 2000h are shown. The mechanical properties of the QPPPTQ anion exchange membrane after alkali immersion show that QPPPTQ still retains a tensile strength of 18.3MPa and an elongation at break of 17.7% after immersion in 1M NaOH solution at 80℃ for 2000h (compared to the retention rates of 62.7% and 61.0% before alkali immersion, respectively). This retention rate of mechanical properties fully meets the requirements for practical applications: the industry generally requires a tensile strength ≥10MPa and an elongation at break ≥5% after alkali immersion.

[0059] Figure 15 The polarization curves of the QPPPTQ anion exchange membrane prepared in Example 1 were recorded during H2-O2 battery testing at 80°C under no back pressure. The test results show that the open-circuit voltage of the QPPPTQ membrane reaches 0.96V, indicating that the membrane has excellent gas barrier performance against H2 and O2, effectively suppressing gas cross-permeation and avoiding battery efficiency loss and safety risks caused by "gas leakage." Furthermore, during the recording of the polarization curves, its peak power density was 5Acm⁻¹. -2 It can reach 774 mW / cm² at current density. -2 This performance index is significantly higher than the peak power density level of most anion exchange membranes currently reported in public publications. This means that the QPPPTQ anion exchange membrane prepared by the method of this invention has excellent comprehensive electrochemical performance, which can further promote the development of the field of anion exchange membrane fuel cells.

[0060] Example 2: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.65 g of pyrene and 2.94 g of p-terphenyl, and dissolve them in 10 mL of dichloromethane to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 2.9 g of 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 10 min, slowly add 12.615 mL of trifluoroacetic acid; after continuing to react in the ice bath for 20 min, remove the ice bath, and place the system at room temperature for 36 h to obtain solution B; add dichloromethane to solution B to dilute it; add the diluted solution B dropwise to methanol to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[pyrene-co-p-terphenylquinine ring] (PPyPTQ).

[0061] Step 2: Weigh 0.5g of PPyPTQ and dissolve it in 7.5ml of LDMF. Stir until the solution is clear and transparent to obtain solution C. Add 0.48g of sodium carbonate and 0.43g of bromomethane to solution C to carry out a quaternization reaction. After reacting at 30℃ for 24h, solution D is obtained. Add ethyl acetate dropwise to solution D to precipitate the product. After filtration and drying, a pale yellow solid is obtained, which is the bromide-form poly[pyrene-co-p-terphenylquinonium] (QPPyPTQ).

[0062] Step 3: Dissolve QPPyPTQ in DMF to obtain a clear and transparent solution E. Pour solution E onto a glass plate of pre-set area and dry it in an oven to obtain the QPPyPTQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPyPTQ membrane in this form is stored in deionized water for subsequent testing.

[0063] After testing, the QPPyPTQ anion exchange membrane prepared in this embodiment exhibited a strength of 225 mS / cm at 80°C. -1 OH - Conductivity, and after soaking in 1M NaOH solution at 80℃ for 2000h, OH - The conductivity retention rate was 91.4%.

[0064] Example 3: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.84 g of phenanthrene and 2.58 g of m-terphenyl, and dissolve them in 10 mL of pyrrolidone to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 3.22 g of 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 15 min, slowly add 2.42 mL of trifluoroacetic acid and 28.8 mL of trifluoromethanesulfonic acid; after continuing the reaction in the ice bath for 30 min, remove the ice bath, and place the system at room temperature for 48 h to obtain solution B; add pyrrolidone to solution B to dilute; add the diluted solution B dropwise to ethanol to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[phenanthrene-co-m-terphenylquinine ring] (PPMTQ).

[0065] Step 2: Weigh 0.5g of PPMTQ and dissolve it in 7.5mL of NMP. Stir until the solution is clear and transparent to obtain solution C. Add 0.63g of sodium bicarbonate and 0.38g of chloromethane to solution C to carry out a quaternization reaction. After reacting at 35℃ for 36h, solution D is obtained. Add solution D dropwise to deionized water to precipitate the solid. After filtration and drying, a pale yellow solid is obtained, which is the chloride-form poly[phenanthrene-co-p-terphenylquinineonium] (QPPMTQ).

[0066] Step 3: Dissolve QPPMTQ in NMP to obtain a clear and transparent solution E. Pour solution E onto a glass plate of pre-defined area and dry it in an oven to obtain the QPPMTQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPMTQ membrane in this form is stored in deionized water for subsequent testing.

[0067] After testing, the QPPMTQ anion exchange membrane prepared in this embodiment exhibited a strength of 232 mS / cm at 80°C. -1 OH - Conductivity, and after soaking in 1M NaOH solution at 80℃ for 2000h, OH - The conductivity retention rate was 92.1%.

[0068] Example 4: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.65 g of pyrene and 1.72 g of biphenyl, and dissolve them in 10 mL of dichloromethane to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 2.58 g of 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 5 min, slowly add 1.21 mL of methanesulfonic acid and 14.4 mL of concentrated nitric acid; after continuing the reaction in the ice bath for 15 min, remove the ice bath, and place the system at room temperature for 24 h to obtain solution B; add dichloromethane to solution B to dilute it; add the diluted solution B dropwise to ethanol to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[pyrene-co-biphenylquinine ring] (PPyBQ).

[0069] Step 2: Weigh 0.5g of PPyBQ and dissolve it in 7.5mL of DMSO. Stir until the solution is clear and transparent to obtain solution C. Add 0.62g of potassium carbonate and 0.64g of iodomethane to solution C to carry out a quaternization reaction. After reacting at 30℃ for 36h, solution D is obtained. Add ethyl acetate dropwise to solution D to precipitate the solid. After filtration and drying, a pale yellow solid is obtained, which is the iodide-form poly[phenanthrene-co-m-terphenylquinineonium] (QPPyBQ).

[0070] Step 3: Dissolve QPPyBQ in DMSO to obtain a clear and transparent solution E. Pour solution E onto a glass plate of pre-set area and dry it in an oven to obtain the QPPyBQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPyBQ membrane in this form is stored in deionized water for subsequent testing.

[0071] After testing, the QPPyBQ anion exchange membrane prepared in this embodiment exhibited a strength of 230 mS / cm at 80°C. -1 OH - Conductivity, and after soaking in 1M NaOH solution at 80℃ for 2000h, OH - The conductivity retention rate is 90.5%.

[0072] Example 5: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.57 g phenanthrene and 2.33 g 1,2-diphenylethane, and dissolve them in 10 mL petroleum ether to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 2.9 g 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 5 min, slowly add 1.21 mL methanesulfonic acid and 14.4 mL trifluoromethanesulfonic acid; after continuing the reaction in the ice bath for 30 min, remove the ice bath, and place the system at room temperature for 24 h to obtain solution B; add petroleum ether to solution B for dilution; add the diluted solution B dropwise to deionized water to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[phenanthrene-co-1,2-diphenylethanequinine ring] (PPBBQ).

[0073] Step 2: Weigh 0.5g of PPBBQ and dissolve it in 7.5ml of LDMF. Stir until the solution is clear and transparent to obtain solution C. Add 0.63g of sodium bicarbonate and 0.43g of bromomethane to solution C to carry out a quaternization reaction. After reacting at room temperature for 24 hours, solution D is obtained. Add solution D dropwise to deionized water to precipitate the solid. After filtration and drying, a pale yellow solid is obtained, which is poly[phenanthrene-co-1,2-diphenylethanequinonium] (QPPBBQ) in the form of iodide ions.

[0074] Step 3: Dissolve QPPBBQ in DMF to obtain a clear and transparent solution E. Pour solution E onto a glass plate of pre-set area and dry it in an oven to obtain a QPPBBQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPBBQ membrane is stored in deionized water for subsequent testing.

[0075] After testing, the QPPBBQ anion exchange membrane prepared in this embodiment exhibited a strength of 231 mS / cm at 80°C. -1 OH - Conductivity, and after soaking in 1M NaOH solution at 80℃ for 2000h, OH - The conductivity retention rate was 90.9%.

[0076] Example 6: This embodiment describes a method for preparing an arylquinonium anion exchange membrane with a conjugated twisted structure, comprising: Step 1: Weigh 0.97 g of pyrene and 2.17 g of 9,9-dimethylfluorene, and dissolve them in 10 mL of dichloromethane to obtain solution A. Add solution A to a single-necked round-bottom flask placed in an ice bath, start stirring, and after it is dissolved evenly, add 2.9 g of 3-quinine cyclohexane hydrochloride; after stirring continuously in the ice bath for 10 min, slowly add 1.21 mL of trifluoroacetic acid and 14.4 mL of concentrated sulfuric acid; after continuing to react in the ice bath for 30 min, remove the ice bath, and place the system at room temperature for 48 h to obtain solution B; add dichloromethane to solution B to dilute it; add the diluted solution B dropwise to ethanol to precipitate, and obtain a pale yellow solid, which is dried under vacuum to obtain poly[pyrene-co-9,9-dimethylfluorenequinine ring] (PPyFQ).

[0077] Step 2: Weigh 0.5g PPyFQ and dissolve it in 7.5mL DMAc. Stir until the solution is clear and transparent to obtain solution C. Add 0.18g sodium hydroxide and 0.25g chloromethane to solution C to carry out a quaternization reaction. After reacting at 35℃ for 12h, solution D is obtained. Add diethyl ether dropwise to solution D to precipitate the solid. After filtration and drying, a pale yellow solid is obtained, which is the chloride-form poly[phenanthrene-co-m-terphenylquinineonium] (QPPyFQ).

[0078] Step 3: Dissolve QPPyFQ in DMAc to obtain a clear and transparent solution E. Pour solution G onto a glass plate of pre-set area and dry it in an oven to obtain the QPPyFQ anion exchange membrane. Then immerse it in the corresponding salt solution to obtain X. - The QPPyFQ membrane in this form is stored in deionized water for subsequent testing.

[0079] After testing, the QPPyFQ anion exchange membrane prepared in this embodiment exhibited a strength of 236 mS / cm at 80°C. -1 OH - Conductivity, and after soaking in 1M NaOH solution at 80℃ for 2000h, OH - The conductivity retention rate was 91.3%.

[0080] In summary, this invention utilizes a superacid-catalyzed polymerization method to prepare an arylquinonium polymer with a conjugated twisted structure. Furthermore, this polymer is used to prepare an arylquinonium anion exchange membrane with a conjugated twisted structure. The resulting anion exchange membrane exhibits high conductivity, high mechanical strength, good alkali resistance and oxidation resistance, and the method is simple and easily industrialized. This type of anion exchange membrane has significant application value in industries involving hydrogen energy, such as alkaline fuel cells, water electrolysis for hydrogen production, flow batteries, and electrochemical ammonia synthesis.

Claims

1. An aryl quaternary phosphonium anion exchange membrane containing a conjugated twisted structure, characterized by, It is prepared from aryl quinolinium polymer containing conjugated twisted structure, wherein the aryl quinolinium polymer containing conjugated twisted structure comprises structural unit shown in formula (I) as follows: （I） Wherein, x represents the proportion of Ar1 unit in Ar1 and Ar2 as a whole, x is a decimal between 0 and 1; X represents anion type, including I, Br, Cl, OH, HCO3.

2. The conjugated twisted structure-containing aryl quaternary phosphonium anion exchange membrane according to claim 1, characterized by, The Ar1 is selected from one of the following structural fragments: 。 3. The conjugated twisted structure-containing aryl quaternary phosphonium anion exchange membrane according to claim 1, characterized in that, The Ar2 is selected from one of the following structural fragments: 。 4. The conjugated twisted structure-containing aryl quaternary phosphonium anion exchange membrane according to claim 1, characterized in that, The aryl quinolinium polymer containing conjugated twisted structure is selected from one of the following structural formulas: 。 5. The method for producing a quaternary ammonium anion exchange membrane containing a conjugated twisted structure according to any one of claims 1 to 4, characterized by, Including: Step 1: Ar1, Ar2 and 3-quinuclidinone hydrochloride are mixed and dissolved in solvent I, catalyst I and catalyst II are added and reacted to obtain aryl quinolinium precursor polymer; Step 2: the precursor polymer is dissolved in solvent III, catalyst III and nucleophile I are added to carry out quaternary ammonium reaction to prepare aryl quinolinium polymer; Step 3: the aryl quinolinium polymer is dissolved in solvent III, filtered to obtain casting solution; Step 4: the casting solution is cast, dried, and then ion exchanged to obtain anion exchange membrane containing conjugated twisted structure.

6. The method for preparing a quaternary ammonium anion exchange membrane containing a conjugated twisted structure according to claim 5, characterized by, Step 1 is specifically: After Ar1 and Ar2 are mixed and added into solvent I, they are dissolved uniformly under ice bath, then 3-quinuclidinone hydrochloride is added, stirred for 5-15 min, catalyst I and catalyst II are slowly added, continuously stirred under ice bath for 10-30 min, then the ice bath is removed, the system is placed at room temperature for reaction for 24-48 h, then solvent I is added for dilution, the diluted solution is added dropwise into solvent II for quenching, then filtered, washed and dried to obtain aryl quinolinium precursor polymer containing conjugated twisted structure.

7. The method for preparing a quaternary ammonium anion exchange membrane containing a conjugated twisted structure according to claim 6, characterized by, The solvent I is one of n-hexane, pyrrolidone, petroleum ether and dichloromethane; the solvent II is one or a mixture of several of methanol, ethanol and deionized water; the catalyst I is one or a mixture of several of methane sulfonic acid and trifluoroacetic acid; the catalyst II is one or a combination of several of trifluoromethane sulfonic acid, trifluoroacetic acid, concentrated sulfuric acid and concentrated nitric acid; the total concentration of Ar1+Ar2 is 1-2 mol / L; the molar ratio of Ar1, Ar2, 3-quinuclidinone hydrochloride, catalyst I and catalyst II is 0.1-0.3:0.7-0.9:1-1.25:1-2:5-10.

8. The method for preparing a quaternary ammonium anion exchange membrane containing a conjugated twisted structure according to claim 5, characterized by, Step 2 is specifically: The precursor polymer is dissolved in solvent III, catalyst III and nucleophile I are added, and the reaction is carried out at 25-35℃ for 12-36 h, then quenched in solvent IV, and then filtered, washed and dried to obtain aryl quinolinium polymer containing conjugated twisted structure.

9. The method for producing a conjugated twisted structure-containing aryl quaternary phosphonium anion exchange membrane according to claim 8, characterized by, The solvent III is one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl pyrrolidone; the catalyst III is one or a mixture of several of potassium carbonate, sodium carbonate, sodium bicarbonate and sodium hydroxide; the nucleophile I is one of iodomethane, bromomethane and chloromethane; the solvent IV is one of diethyl ether, ethyl acetate and deionized water; the molar ratio of the precursor polymer, catalyst III and nucleophile I is 1:2-5:2-5.

10. The method for preparing a quaternary ammonium anion exchange membrane containing a conjugated twisted structure according to claim 5, characterized by, In Step 3, the aryl quinolinium polymer is dissolved in a solvent III, and filtered through a 5-μm needle filter to obtain a casting solution, wherein the solvent III is dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide or N-methyl pyrrolidone; In Step 4, the casting solution is cast on a glass plate with a predetermined area, and after drying, the obtained polymer film is immersed in a salt solution for ion exchange to obtain an aryl quinolinium polymer film containing a conjugated twisted structure.

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