Carboxyl-containing polyarylene polymers and methods for their preparation, ionic solvated films and methods for their preparation and use

Abstract

The application provides a carboxyl-containing polyarylene polymer and a preparation method thereof, an ionic solvated film and a preparation method and application thereof. The polymer is a polymer comprising a repeating structural unit of the following formula I: formula I; wherein Ar is a group comprising an aromatic ring structure; R1 is a 2-carbonyl indole ring group without carboxyl substitution; R2 is a 2-carbonyl indole ring group with carboxyl substitution; x is a functionalization degree, 0 < x < 1; and the number average molecular weight of the carboxyl-containing polyarylene polymer is 30000-500000. Through precise control of the carboxyl content in the polymer, efficient optimization of the functionalization degree of the material is realized. The obtained ionic solvated film exhibits excellent ionic conductivity, low surface resistance and good long-term running stability under high-temperature and strong-alkali conditions, and is suitable for electrochemical devices such as alkaline electrolytic water hydrogen production and alkaline fuel cells.

Description

Technical Field

[0001] This application relates to the field of ion solvation membrane preparation technology for hydrogen production by water electrolysis, specifically to a carboxyl-containing polyarylene polymer and its preparation method, an ion solvation membrane and its preparation method and application. Background Technology

[0002] Hydrogen energy is considered an important secondary energy source for building a low-carbon energy system due to its high energy density, clean combustion products, and wide availability. Among the current mainstream hydrogen production technologies, water electrolysis can achieve near-zero carbon emissions under renewable energy power supply conditions, making it a key route for green hydrogen production.

[0003] Water electrolysis technologies mainly include alkaline water electrolysis, proton exchange membrane (PEM) water electrolysis, and anion exchange membrane (EEM) water electrolysis. Traditional alkaline water electrolysis uses porous membranes, which suffer from poor ion selectivity and insufficient gas barrier properties, making it difficult to operate at high current densities. While PEM water electrolysis is highly efficient and compact, it relies on expensive perfluorosulfonic acid membranes and noble metal catalysts, resulting in high costs. Anion exchange membrane (EEM) water electrolysis operates under alkaline conditions and can utilize non-noble metal catalysts, offering a potential balance between cost and efficiency, and is currently a hot research topic.

[0004] However, the ion conduction of existing anion exchange membranes relies on fixed cationic groups (such as quaternary ammonium and imidazolium). These groups are prone to chemical degradation under strong alkaline, high-temperature, and high-potential environments, leading to decreased membrane performance and insufficient stability. Therefore, developing novel membrane materials that combine high ion conductivity, excellent alkali resistance, and good mechanical properties is of great significance.

[0005] In recent years, a novel type of membrane material that does not rely on fixed ionic groups—ion-solvating membranes (ISMs)—has attracted attention. These membranes form dynamic ion conduction channels through the interaction between polar functional groups in the polymer backbone and the solvent, achieving efficient hydroxyl ion migration. Because their structure does not contain easily degradable fixed cation groups, their theoretical chemical stability is significantly improved, providing a new direction for overcoming the stability bottleneck of traditional anion exchange membranes.

[0006] Nevertheless, ion-solvated membranes still face challenges such as the difficulty in balancing conductivity and mechanical properties, the complexity of controlling the solvation microenvironment, and the lack of scalable preparation methods. Therefore, developing novel polymer membrane materials with well-defined structures, tunable properties, high conductivity, excellent alkali resistance, and good mechanical properties is crucial for promoting the development of next-generation high-performance, long-life alkaline water electrolysis technology. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a carboxyl-containing polyarylene polymer and its preparation method, an ion-solvation membrane and its preparation method, and its applications. The ion-solvation membrane is constructed based on this carboxyl-containing polyarylene polymer material, exhibiting both good chemical stability and structural rigidity. By precisely controlling the carboxyl content in the polymer, the degree of material functionalization can be effectively optimized. The introduction of carboxyl groups helps to construct a complete ion-solvation network, significantly enhancing the membrane's adsorption and retention capacity for water molecules and alkaline electrolytes. Thus, without sacrificing mechanical properties, a significant increase in hydroxide ion conductivity and a decrease in sheet resistivity are simultaneously achieved.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a carboxyl-containing polyarylene polymer, which is a polymer comprising repeating structural units of the following formula I: Formula I; Wherein, Ar is a group containing an aromatic ring structure; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1; The number average molecular weight of the carboxyl-containing polyarylene polymer is 30,000-500,000.

[0009] Preferably, the functionalization degree x is 0.6-1.

[0010] Preferably, Ar is selected from substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted tetraphenylene, diphenylene linked by C1-C6 alkylene, substituted or unsubstituted phenanthyl, substituted or unsubstituted binaphthyl, substituted or unsubstituted dibenzoxycyclic dimethyl, and substituted or unsubstituted fluorene dimethyl.

[0011] Preferably, Ar is selected from the group consisting of: ; Where n is an integer from 1 to 4.

[0012] Preferably, R1 is selected from the group consisting of: .

[0013] Preferably, R2 is selected from the group consisting of: .

[0014] Preferably, the repeating structural unit of the carboxyl-containing polyarylene polymer is selected from any one of the following structural formulas: .

[0015] Secondly, the present invention provides a method for preparing a carboxyl-containing polyarylene polymer, comprising the following steps: Aromatic monomers and ketone monomers are dissolved in a first solvent and stirred to obtain a first mixture; At -5℃ to -5℃, an acid catalyst is added to the first mixture to carry out a polymerization reaction, resulting in a second mixture; The second mixture is poured into the second solvent, and solid substances precipitate out; The solid material was neutralized, washed with deionized water, filtered and separated, and dried to obtain a carboxyl-containing polyarylene polymer with a number average molecular weight of 30,000-500,000. The carboxyl-containing polyarylene polymer is formed from a polymer comprising repeating structural units of Formula I: Formula I; The ketone monomer is any one of the following: i. Monomers containing R1 substituents and monomers containing R2 substituents; ii. Monomers containing R2 substituents; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1。

[0016] Preferably, the first solvent includes at least one of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; The second solvent includes at least one of methanol, ethanol, and water; The acid catalyst includes at least one of trifluoromethanesulfonic acid and methanesulfonic acid.

[0017] Preferably, when adding the acid catalyst to the first mixture, an acidity regulator is also added; The acidity regulator includes at least one of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid. The volume ratio of the acid catalyst to the acidity regulator is (0.9-10):1.

[0018] Preferably, the molar ratio of the aromatic monomer to the ketone monomer is 1:(1.1-1.3), and the volume ratio of the first solvent to the acid catalyst is 1:(3-6).

[0019] Preferably, when the monomer includes a monomer containing an R1 substituent and a monomer containing an R2 substituent, the molar ratio of the monomer containing an R1 substituent to the monomer containing an R2 substituent is 0.008-120.

[0020] Thirdly, the present invention provides an ion-solventizing membrane comprising a carboxyl-containing polyarylene polymer as described in any one of the first aspects above.

[0021] Fourthly, the present invention provides a method for preparing the ion-solvated film described in the third aspect above, comprising the following steps: The carboxyl-containing polyarylene polymer is dissolved in an organic solvent to form a uniform casting solution; The casting solution is poured onto a substrate and dried to remove the solvent to form a self-supporting film. The self-supporting membrane was demolded in water to obtain an ion-solventized membrane; The organic solvent includes at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide; The mass concentration of the casting solution is 0.05-0.10 g / mL; The thickness of the ion-solventized film is 20-120 μm.

[0022] Furthermore, the present invention also provides an application of the ion solvation membrane described in the third aspect above in water electrolysis for hydrogen production or in alkaline fuel cells.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) Excellent alkali stability: The carboxyl group in the side chain of the polyarylene polymer containing carboxyl group can form a stable synergistic ion pair with the carbonyl group on the 2-carbonylindole ring under alkaline conditions, thereby significantly improving the long-term chemical stability of the material under strong alkali and high temperature environments.

[0024] (2) Synergistic improvement of ionic conductivity and mechanical strength: By regulating the carboxyl content, the ionic solvation network can be optimized, which can significantly improve hydroxide ion conductivity and reduce surface resistance while maintaining good mechanical properties.

[0025] (3) Outstanding comprehensive electrochemical performance: The obtained ion solvation membrane has high conductivity, low resistance and high durability under high temperature and strong alkaline conditions, and is suitable for alkaline water electrolysis to produce hydrogen, alkaline fuel cells and other devices.

[0026] (4) Controllable preparation and wide applicability: The preparation method can achieve precise control of polymer structure and functionalization degree, and the material system can be extended to various alkaline electrochemical application scenarios that require high stability and high ionic conductivity. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The 1H NMR spectrum of the carboxyl-containing polyarylene polymer Ib in Example 2; Figure 2 The 1H NMR spectrum of the carboxyl-containing polyarylene polymer Ic in Example 3; Figure 3 The 1H NMR spectrum of the carboxyl-containing polyarylene polymer Id in Example 4; Figure 4 The 1H NMR spectrum of the carboxyl-containing polyarylene polymer Ie in Example 5; Figure 5 The 1H NMR spectrum of the carboxyl-containing polyarylene polymer Ig in Example 7; Figure 6 The 1H NMR spectrum of polyarylene polymer B in Comparative Example 1 is shown. Figure 7 The polarization curves are for the ion-solventized films prepared in Examples 1-7 and Comparative Example 1. Figure 8 The polarization curves are for the ion-solventized films prepared in Examples 8-10; Figure 9 The polarization curves are those of the ion-solvated films prepared in Examples 11-13; Figure 10 This is a test graph showing the stability of the ion-solventized membrane prepared in Example 7 for hydrogen production via water electrolysis. Figure 11 The swelling diagrams are of the ion-solventized films prepared in Examples 3, 7 and Comparative Example 1. Figure 12 The wet composition diagram shows the ion-solventized films prepared in Examples 3, 7 and Comparative Example 1. Detailed Implementation

[0029] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] As used herein, the term "2-carbonylindole cyclogroup" refers to a group having an indole-2-one skeleton, with the following general formula: ; Among them, positions 4 to 7 (R4-R7) can each be independently hydrogen, halogen, C1-C6 alkyl, or nitro; and the 2-carbonyl indole ring group is connected to the polymer backbone at the 3-carbon atom position on the ring; the "2-carbonyl" specifically refers to the carbonyl (C=O) functional group at the 2-position of the indole ring, which belongs to the ketone carbonyl structure and is distinct from and does not contain a carboxyl group (-COOH).

[0031] The term "without carboxyl substitution" as used herein refers to the fact that the ring atoms of the 2-carbonylindole cyclic group are not substituted by carboxyl (-COOH) functional groups, but the cyclic group itself may contain its inherent carbonyl (C=O) structure. An example of "R1 being a 2-carbonylindole cyclic group without carboxyl substitution" can be given as follows: .

[0032] The phrase "having a carboxyl-substituted group" as used herein refers to a carboxyl functional group attached to the benzene ring of the 2-carbonylindole ring. An example of "R2 being a 2-carbonylindole ring with a carboxyl-substituted group" can be cited as follows: .

[0033] Examples of C1-C6 alkyl groups include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, etc.

[0034] Examples of C1-C6 alkylene groups include: methylene (-CH2-), 1,2-ethylene (-CH2CH2-), 1,3-propylene (-CH2CH2CH2-), 1,2-propylene (-CH2CH(CH3)-), 1,4-butylene (-CH2CH2CH2CH2-), etc.

[0035] This invention provides a carboxyl-containing polyarylene polymer, which is a polymer comprising repeating structural units of Formula I: Formula I; Wherein, Ar is a group containing an aromatic ring structure; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1; The number average molecular weight of the carboxyl-containing polyarylene polymer is 30,000-500,000.

[0036] In this embodiment of the invention, the carboxyl-containing polyarylene polymer has a 2-carbonylindole cyclic group modified on its side chain. This cyclic group is connected to the polymer backbone at the 3-carbon atom position, and a carboxyl functional group is attached to its benzene ring portion. In an alkaline electrolyte, the carboxyl functional group and the carbonyl structure of the 2-carbonylindole cyclic group can synergistically form a stable complex ion pair, thereby endowing the membrane with excellent long-term chemical stability in a strongly alkaline environment.

[0037] By precisely controlling the degree of introduction of carboxyl functional groups into the polymer, the ionic functionalization of the material can be finely adjusted. The introduction of carboxyl functional groups helps to form and improve the ion solvation network within the membrane, significantly enhancing the membrane's ability to adsorb and retain water molecules and alkaline electrolytes. Thus, while maintaining the original mechanical integrity of the material, a significant increase in hydroxide ion conductivity and an effective reduction in membrane surface resistance are simultaneously achieved.

[0038] In some embodiments, the functionality degree x can be any value between 0.01 and 1, such as 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, and 1.

[0039] In a preferred embodiment, the functionalization degree x is 0.6-1.

[0040] In some embodiments, Ar is selected from substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted tetraphenylene, diphenylene linked by C1-C6 alkylene, substituted or unsubstituted phenanthrene, substituted or unsubstituted binaphthyl, substituted or unsubstituted dibenzoxycyclic dimethyl, and substituted or unsubstituted fluorene dimethyl.

[0041] In some embodiments, Ar is selected from the group consisting of: ; Where n is an integer from 1 to 4. In the example, the integers n from 1 to 4 can be 1, 2, 3, or 4.

[0042] In some embodiments, R1 is selected from the group consisting of: .

[0043] In some embodiments, R2 is selected from the group consisting of: .

[0044] In some embodiments, the repeating structural units of the carboxyl-containing polyarylene polymer are selected from any of the following structural formulas: .

[0045] This application further provides a method for preparing the above-mentioned carboxyl-containing polyarylene polymer, comprising the following steps: Aromatic monomers and ketone monomers are dissolved in a first solvent and stirred to obtain a first mixture; At -5℃ to -5℃, an acid catalyst is added to the first mixture to carry out a polymerization reaction, resulting in a second mixture; The second mixture is poured into the second solvent, and solid substances precipitate out; The solid material was neutralized, washed with deionized water, filtered and separated, and dried to obtain a carboxyl-containing polyarylene polymer with a number average molecular weight of 30,000-500,000. The carboxyl-containing polyarylene polymer is formed from a polymer comprising repeating structural units of Formula I: Formula I; The ketone monomer is any one of the following: i. Monomers containing R1 substituents and monomers containing R2 substituents; ii. Monomers containing R2 substituents; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1。

[0046] In some embodiments, the number average molecular weight of the carboxyl-containing polyarylene polymer can be 30,000, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, or 500,000.

[0047] In this embodiment of the invention, the first solvent serves as the polymerization reaction medium, used to dissolve aromatic monomers and ketone monomers to form a homogeneous reaction system; the second solvent serves as a poor solvent, causing the carboxyl-containing polyarylene polymer generated after the polymerization reaction to precipitate out.

[0048] In some embodiments, the first solvent includes at least one of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone.

[0049] In some embodiments, the second solvent includes at least one of methanol, ethanol, and water.

[0050] In some embodiments, the acid catalyst includes at least one of trifluoromethanesulfonic acid and methanesulfonic acid.

[0051] In some embodiments, when adding the acid catalyst to the first mixture, an acidity regulator is also added; The acidity regulator includes at least one of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid. The volume ratio of the acid catalyst to the acidity regulator is (0.9-10):1.

[0052] In this embodiment of the invention, the acidity regulator can establish a dynamic protonation equilibrium with the acid catalyst. By reversibly binding and releasing protons, the acidity regulator adjusts the effective proton concentration of the acid catalyst in the system, thereby controlling the polymerization rate and suppressing crosslinking side reactions.

[0053] In the example, the volume ratio of the acid catalyst to the acidity regulator can be 0.9:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1.

[0054] In some embodiments, the acidity regulator and the acid catalyst may be premixed or added separately or simultaneously.

[0055] In some embodiments, the neutralization method includes adding an aqueous sodium bicarbonate solution to the reaction system and stirring until the pH of the reaction system is 6-8.

[0056] In some embodiments, the neutralization method includes adding an aqueous solution of potassium carbonate to the reaction system and stirring until the pH of the reaction system is 6-8.

[0057] In a preferred embodiment, the water is deionized water.

[0058] The present invention does not have special requirements for the filtration, separation, and drying operations, and conventional techniques in the art can be used. Filtration aims to achieve solid-liquid separation and can be accomplished using conventional filtration devices and methods; drying aims to remove residual solvent and can be achieved using common drying methods in the art, such as vacuum drying, forced-air drying, and oven drying.

[0059] In some embodiments, the molar ratio of the aromatic monomer to the ketone monomer is 1:(1.1-1.3), and the volume ratio of the first solvent to the acid catalyst is 1:(3-6).

[0060] In some embodiments, the volume ratio of the first solvent to the acid catalyst can be 1:3.0, 1:3.5, 1:4.0, 1:4.5, 1:5.0, 1:5.5, or 1:6.0.

[0061] In some embodiments, when the monomer includes a monomer containing an R1 substituent and a monomer containing an R2 substituent, the molar ratio of the monomer containing the R1 substituent to the monomer containing the R2 substituent is 0.008-120, for example 0.008, 0.1, 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120.

[0062] In a preferred embodiment, when the monomer includes a monomer containing an R1 substituent and a monomer containing an R2 substituent, the molar ratio of the monomer containing an R1 substituent to the monomer containing an R2 substituent is 0.01-0.66.

[0063] This application further provides an ion-solvation membrane comprising a carboxyl-containing polyarylene polymer as described in any of the preceding embodiments.

[0064] This application also provides a method for preparing the above-mentioned ion-solvated film, comprising the following steps: The carboxyl-containing polyarylene polymer is dissolved in an organic solvent to form a uniform casting solution; The casting solution is poured onto a substrate and dried to remove the solvent to form a self-supporting film. The self-supporting membrane was demolded in water to obtain an ion-solventized membrane; The organic solvent includes at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide; The mass concentration of the casting solution is 0.05-0.10 g / mL; The thickness of the ion-solventized film is 20-120 μm.

[0065] In the example, the thickness of the ion-solventized film can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, or 120μm.

[0066] In some embodiments, the substrate is made of materials such as glass or stainless steel.

[0067] In some embodiments, the drying temperature for removing the solvent is 60-80°C. In exemplary embodiments, the drying temperature for removing the solvent can be 60°C, 65°C, 70°C, 75°C, or 80°C.

[0068] Furthermore, this application also provides the application of the ion solvation membrane described above in water electrolysis for hydrogen production or in alkaline fuel cells.

[0069] To further illustrate the technical effects of the present invention, the following specific embodiments are also provided.

[0070] Example 1 Example 1 provides a carboxyl-containing polyarylene polymer (polymer Ia), the preparation method of which includes the following steps: Polymer Ia has the following repeating structural unit (denoted as structural formula I-1): ; The polymer preparation method is as follows: Step 1: In a dry reaction vessel, dissolve 1.54 g biphenyl (10 mmol), 1.75 g 2,3-diketone dihydroindole (indigo) (11.88 mmol), and 0.02 g 2,3-dioxoindoline-7-carboxylic acid (0.12 mmol) in 2 mL of the first solvent (dichloromethane) and stir at 0 °C for 30 min to completely dissolve the monomers.

[0071] Step 2: Maintain the reaction system from Step 1 at 0°C and add the acid catalyst (2 mL trifluoroacetic acid, followed by 8 mL trifluoromethanesulfonic acid) dropwise to the system. After the addition is complete, continue stirring until a viscous polymer solution is obtained. Slowly pour this viscous solution into an excess of the second solvent (ethanol), precipitating fibrous polymer. Subsequently, place the fibrous polymer in an aqueous potassium carbonate solution and treat it at 80°C for 24 h, then wash it with deionized water for 48 h. Finally, dry the washed fibrous polymer at 60°C under vacuum for 24 h to obtain polymer Ia with a carboxyl functionalization degree of 1%.

[0072] Example 1 also provides an ion-solvated membrane formed from the above-described polymer Ia. The preparation method of this ion-solvated membrane includes the following steps: The polymer Ia was dissolved in dimethyl sulfoxide to prepare a homogeneous casting solution with a mass fraction of 5 wt%. This casting solution was poured onto a horizontally placed clean glass plate and dried at 60°C for 24 h, followed by further drying at 80°C under vacuum for 24 h to form a self-supporting membrane. The resulting self-supporting membrane was then demolded in deionized water to obtain an ion-solventized membrane formed from polymer Ia with a thickness of 40 ± 5 μm.

[0073] Example 2 Example 2 provides a carboxyl-containing polyarylene polymer (polymer Ib).

[0074] Polymer Ib has the following repeating structural units (denoted as structural formula I-2): ; The preparation method of polymer Ib is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol), 1.41 g 2,3-diketone dihydroindole (indigo) (9.6 mmol), and 0.46 g 2,3-dioxoindoline-7-carboxylic acid (2.4 mmol). The remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum of polymer Ib is as follows. Figure 1 As shown.

[0075] Example 2 also provides an ion-solvated membrane formed from the above-described polymer Ib. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 35 ± 5 μm.

[0076] Example 3 Example 3 provides a carboxyl-containing polyarylene polymer (polymer Ic).

[0077] Polymer Ic has the following repeating structural unit (denoted as structural formula I-3): ; The preparation method of polymer Ic is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol), 1.06 g 2,3-diketone dihydroindole (indigo) (7.2 mmol), and 0.92 g 2,3-dioxoindoline-7-carboxylic acid (4.8 mmol). The remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum of polymer Ic is as follows. Figure 2 As shown.

[0078] Example 3 also provides an ion-solvated membrane formed from the above-described polymer Ic. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 20 ± 5 μm.

[0079] Example 4 Example 4 provides a carboxyl-containing polyarylene polymer (polymer Id).

[0080] Polymer Id has the following repeating structural unit (denoted as structural formula I-4): ; The preparation method of polymer Id is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol), 0.71 g 2,3-diketone dihydroindole (indigo) (4.8 mmol), and 1.38 g 2,3-dioxoindoline-7-carboxylic acid (7.2 mmol). The remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum of polymer Id is as follows. Figure 3 As shown.

[0081] Example 4 also provides an ion-solvated membrane formed from the above-described polymer Id. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 30 ± 5 μm.

[0082] Example 5 Example 5 provides a carboxyl-containing polyarylene polymer (polymer Ie).

[0083] Polymer Ie has the following repeating structural units (denoted as structural formula I-5): ; The preparation method of polymer Ie is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol), 0.35 g 2,3-diketone dihydroindole (indigo) (2.4 mmol), and 1.83 g 2,3-dioxoindoline-7-carboxylic acid (9.6 mmol). The remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum of polymer Ie is as follows. Figure 4 As shown.

[0084] Example 5 also provides an ion-solvated membrane formed from the above-described polymer Ie. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 25 ± 5 μm.

[0085] Example 6 Example 6 provides a carboxyl-containing polyarylene polymer (polymer If).

[0086] The polymer If has the following repeating structural unit (denoted as structural formula I-6): ; The preparation method of polymer If is basically the same as that of Example 1. The monomers used for polymerization are: 1.54 g biphenyl (10 mmol), 0.18 g 2,3-diketone dihydroindole (indigo) (1.2 mmol), and 2.06 g 2,3-dioxoindoline-7-carboxylic acid (10.8 mmol). The remaining steps and parameters are the same as those in Example 1.

[0087] Example 6 also provides an ion-solvated membrane formed from the above-described polymer If. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 45 ± 5 μm.

[0088] Example 7 Example 7 provides a carboxyl-containing polyarylene polymer (polymer Ig).

[0089] Polymer Ig has the following repeating structural units (denoted as structural formula I-7):

[0090] The preparation method of polymer Ig is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol) and 2.29 g 2,3-dioxoindoline-7-carboxylic acid (12 mmol), and the remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum (¹H NMR) of polymer Ig is as follows. Figure 5 As shown.

[0091] Example 7 also provides an ion-solvated membrane formed from the above-described polymer Ig. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 30 ± 5 μm.

[0092] Example 8 Example 8 provides a carboxyl-containing polyarylene polymer (polymer Ih).

[0093] Polymer Ih has the following repeating structural units (denoted as structural formula I-8): ; The preparation method of polymer Ih is basically the same as that of Example 1, wherein the monomers are: 1.54g biphenyl (10 mmol) and 2.48g 2,3-dioxoindoline-6-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0094] Example 8 also provides an ion-solvated membrane formed from the above-described polymer Ih. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 35 ± 5 μm.

[0095] Example 9 Example 9 provides a carboxyl-containing polyarylene polymer (polymer Ii).

[0096] Polymer Ii has the following repeating structural units (denoted as structural formula I-9): ; The preparation method of polymer Ii is basically the same as that of Example 1, wherein the monomers are: 1.54g biphenyl (10 mmol) and 2.48g 2,3-dioxoindoline-5-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0097] Example 9 also provides an ion-solvated membrane formed from the above-described polymer Ii. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 30 ± 5 μm.

[0098] Example 10 Example 10 provides a carboxyl-containing polyarylene polymer (polymer Ij).

[0099] Polymer Ij has the following repeating structural unit (denoted as structural formula I-10): ; The preparation method of polymer Ij is basically the same as that of Example 1, wherein the monomers are: 1.54g biphenyl (10 mmol) and 2.48g 2,3-dioxoindoline-4-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0100] Example 10 also provides an ion-solvation membrane formed from the above-described polymer Ij. This ion-solvation membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvation membrane is 45 ± 5 μm.

[0101] Example 11 Example 11 provides a carboxyl-containing polyarylene polymer (polymer Ik).

[0102] Polymer Ik has the following repeating structural unit (denoted as structural formula I-11): ; The preparation method of polymer Ik is basically the same as that of Example 1, wherein the monomers are: 2.3g terphenyl (10 mmol) and 2.48g 2,3-dioxoindoline-6-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0103] Example 11 also provides an ion-solvated membrane formed from the above-described polymer Ik. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 50 ± 5 μm.

[0104] Example 12 Example 12 provides a carboxyl-containing polyarylene polymer (polymer II).

[0105] Polymer Il has the following repeating structural unit (denoted as structural formula I-12): ; The preparation method of polymer II is basically the same as that of Example 1, wherein the monomers are: 1.82g 1,2-diphenylethane (10 mmol) and 2.48g 2,3-dioxoindoline-5-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0106] Example 12 also provides an ion-solvated membrane formed from the above-described polymer Il. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 35 ± 5 μm.

[0107] Example 13 Example 13 provides a carboxyl-containing polyarylene polymer (polymer Im).

[0108] Polymer Im has the following repeating structural unit (denoted as structural formula I-13): ; The preparation method of polymer Im is basically the same as that of Example 1, wherein the monomers are: 1.66g fluorene (10 mmol) and 2.48g 2,3-dioxoindoline-7-carboxylic acid (13 mmol), and the remaining steps and parameters are the same as those in Example 1.

[0109] Example 13 also provides an ion-solvated membrane formed from the above-described polymer Im. This ion-solvated membrane was prepared according to the method described in Example 1, and the thickness of the resulting ion-solvated membrane is 25 ± 5 μm.

[0110] Comparative Example 1 Comparative Example 1 provides a polyarylene polymer (polymer B).

[0111] Polymer B has the following repeating structural unit (denoted as structural formula B-1): ; The preparation method of polymer B is basically the same as that in Example 1, wherein the monomers are: 1.54 g biphenyl (10 mmol) and 1.77 g 2,3-diketone dihydroindole (indigo) (12 mmol), and the remaining steps and parameters are consistent with those in Example 1. The 1H NMR spectrum of polymer B is as follows. Figure 6 As shown.

[0112] Comparative Example 1 also provides an ion-solvation membrane formed from the above-described polymer B. This ion-solvation membrane was prepared according to the preparation method described in Example 1, and the thickness of the resulting ion-solvation membrane was 30 ± 5 μm.

[0113] Application of ion-solvating membranes in alkaline water electrolysis: The ion-solubilized membranes prepared in Examples 1-13 and Comparative Example 1 were assembled in an alkaline water electrolysis test apparatus. Using 200 mL of 6M KOH aqueous solution as the electrolyte, water electrolysis tests were conducted at 80°C. By adjusting the applied current density, the corresponding electrolysis voltage was recorded, and polarization curves were plotted to evaluate the electrolytic performance of the ion-solubilized membranes. To maintain a stable test environment, the electrolyte was replaced every three days to examine the long-term operational stability of the ion-solubilized membranes.

[0114] Figure 7 The polarization curves are for the ion-solventized films prepared in Examples 1-7 and Comparative Example 1.

[0115] Figure 7 The polarization curves of the ion-solvated films prepared in Examples 1-7 and Comparative Example 1 are shown under the conditions of 6 M KOH and 80 °C. Figure 7 As shown, as the degree of functionalization (x) of the side chain carboxyl groups gradually increases from 0.01 (Example 1) to 1 (Example 7), the polarization curve exhibits a systematic downward trend. This indicates that under the same operating voltage, the current density increases significantly and the ohmic overpotential decreases significantly.

[0116] In particular, Example 7 (x=1) showed significantly better performance than Comparative Example 1 (without carboxyl groups) and the low-functionalization sample. This result directly demonstrates that the continuous hydrophilic ion channels constructed by regulating the carboxyl group content effectively reduced the membrane sheet resistance and improved ion transport kinetics, thereby achieving steady optimization of electrolysis performance.

[0117] Figure 8 The graphs show the polarization curves of the ion-solvated films prepared in Examples 8-10. Figure 9 The polarization curves are for the ion-solventized films prepared in Examples 11-13. Figure 8 and Figure 9 The polarization curves shown further verify the universality and structural regulation capability of the carboxyl functionalization strategy. Examples 8-10 ( Figure 8 ) and Examples 11-13 ( Figure 9 The effects of polyarylene polymers with different main chain structures on membrane properties were investigated under the condition that the degree of functionalization of the side chain carboxyl groups (x) was 1.0.

[0118] Figure 10 This is a stability test graph of the ion-solventized membrane prepared in Example 7 for hydrogen production via water electrolysis. Under electrolysis conditions of 6 M KOH and 80°C, the membrane exhibited in-situ operational stability exceeding 1600 h. This result demonstrates that the ion-solventized membrane prepared by the method of this invention exhibits significantly improved long-term chemical stability under strong alkaline and high-temperature environments.

[0119] The hydrophilicity and dimensional stability of ion-solvated membranes were evaluated by testing the swelling degree. Ion-solvated membrane samples were cut into 2cm × 2cm squares and immersed in 6M KOH solution at 80℃ for 240h. After removal, residual liquid was wiped off with lint-free paper, and the dry film area (S) was measured. dry ), wet film area (S) wet ), dry film thickness (T) dry ), wet film thickness (T) wet ), dry film volume (V) dry ), wet film volume (V) wet And calculate the swelling ratio (SR) using the following formula: Area swelling degree SR Area : ; Thickness Swelling Degree SR Thickness : ; Volume swelling degree SR Volume : .

[0120] Figure 11 The swelling data of the ion-solventized films prepared in Examples 3, 7 and Comparative Example 1 are shown in the graph. Figure 11 The swelling behavior of ion-solvated membranes with different degrees of carboxyl functionalization was demonstrated. Compared with the unmodified Comparative Example 1, Examples 3 and 7, which introduced carboxyl groups, exhibited significant volume swelling, especially Example 7 (x=1), which showed a volume swelling degree as high as 160%. This indicates that the introduction of carboxyl groups improves the hydrophilicity and electrolyte holding capacity of the membrane material and may be beneficial to the formation of an intramembrane ion transport environment.

[0121] The composition of polymer, water, and alkali in an alkaline environment was analyzed by measuring the mass of ion-solventized membranes. Membrane samples were cut into 2cm × 2cm squares and immersed in 6M KOH solution at 80℃ for 240 hours. After removal, the surface residue was wiped off with lint-free paper, and the wet membrane mass (m) was measured. wet The dry film mass (m) after the wet film is dried at 120℃ for 12 hours dry The mass (m) of the wet film after washing with deionized water to neutral pH and then drying at 120°C for 12 hours was also measured. dedoped By comparing the above quality differences, the distribution and composition of polymer, water, and alkali in the ion-solventized membrane under alkaline treatment conditions can be evaluated. The calculation formula is as follows: Polymer mass percentage W polymer : ; Water quality percentage W water : ; Alkali mass percentage Walkali : .

[0122] Figure 12 The wet composition diagram shows the ion-solventized films prepared in Examples 3, 7 and Comparative Example 1. Figure 12 The wet composition of ion-solvated membranes with different degrees of carboxyl functionalization was shown. Compared with Comparative Example 1, Example 7 (x=1) had a wet water content as high as 39.8%, and the proportion of KOH component in the membrane was significantly increased. This indicates that the introduction of carboxyl groups improves the membrane material's ability to hold water and electrolyte, and may be conducive to the formation of an ion-solvated environment within the membrane.

[0123] The ion conductivity of the ion-solvated membrane under alkaline conditions was investigated by conductivity testing. Membrane samples were cut into 3cm × 3cm squares and immersed in a 6M KOH solution at 80℃ for 240 hours. Subsequently, the treated ion-solvated membrane sheets were assembled into a conductivity testing device, and their ion conductivity was measured at 80℃ and 6M KOH.

[0124] The ionic conductivity test results of the ion-solventized membranes prepared in Examples 1-13 and Comparative Example 1 are listed in Table 1.

[0125] Table 1. Ionic conductivity of the ion-solvated films prepared in Examples 1-13 and Comparative Example 1

[0126] Based on the data analysis of Examples 1-13 and Comparative Example 1 in Table 1, the results are as follows: The polyarylene polymer synthesized in Comparative Example 1 did not contain carboxyl functional groups in its side chains. The carboxyl-containing polyarylene polymers synthesized in Examples 1 to 7 had a side chain carboxyl functionalization degree (x) that gradually increased from 0.01 to 1.0. The side chain carboxyl functionalization degree (x) in Examples 8 to 13 was 1.0.

[0127] Ionic conductivity tests showed that the conductivity of the ion-solventized membrane generally increased with the increase of carboxyl functionalization degree x (Examples 1-7). By precisely controlling the carboxyl content in the polymer, the degree of material functionalization can be effectively optimized. The introduction of carboxyl groups helps to construct a complete ion-solventization network, significantly enhancing the membrane's adsorption and retention capacity for water molecules and alkaline electrolytes. Thus, without sacrificing mechanical properties, a significant increase in hydroxide ion conductivity and a decrease in sheet resistance are simultaneously achieved.

[0128] This invention, through a carboxyl functionalization strategy, not only avoids the problem of nucleophilic substitution and degradation of fixed cation groups in traditional anion exchange membranes, but also achieves a steady improvement in electrolytic performance while maintaining long-term operational stability. Furthermore, the preparation method is simple, produces high-purity products, and has promising application prospects.

[0129] Compared with the prior art, the present invention has the following beneficial effects: (1) Excellent alkali stability: The carboxyl group in the side chain of the polyarylene polymer containing carboxyl group can form a stable synergistic ion pair with the carbonyl group on the 2-carbonylindole ring under alkaline conditions, thereby significantly improving the long-term chemical stability of the material under strong alkali and high temperature environments.

[0130] (2) Synergistic improvement of ionic conductivity and mechanical strength: By regulating the carboxyl content, the ionic solvation network can be optimized, which can significantly improve hydroxide ion conductivity and reduce surface resistance while maintaining good mechanical properties.

[0131] (3) Outstanding comprehensive electrochemical performance: The obtained ion solvation membrane has high conductivity, low resistance and high durability under high temperature and strong alkaline conditions, and is suitable for alkaline water electrolysis to produce hydrogen, alkaline fuel cells and other devices.

[0132] (4) Controllable preparation and wide applicability: The preparation method can achieve precise control of polymer structure and functionalization degree, and the material system can be extended to various alkaline electrochemical application scenarios that require high stability and high ionic conductivity.

[0133] The specific embodiments of the present invention have been described above. It should be understood that the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A carboxyl-containing polyarylene polymer, characterized in that, For polymers containing repeating structural units of the following formula I: Equation I; Wherein, Ar is a group containing an aromatic ring structure; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1; The number average molecular weight of the carboxyl-containing polyarylene polymer is 30,000-500,000.

2. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, The functionalization degree x is 0.6-1.

3. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, Ar is selected from substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted tetraphenylene, diphenylene linked by C1-C6 alkylene, substituted or unsubstituted phenanthrene, substituted or unsubstituted binaphthyl, substituted or unsubstituted dibenzoxyheterocyclic dimethyl, and substituted or unsubstituted fluorene dimethyl.

4. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, Ar is selected from the group consisting of the following groups: ； Where n is an integer from 1 to 4.

5. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, R1 is selected from the group consisting of the following groups: 。 6. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, R2 is selected from the group consisting of the following groups: 。 7. The carboxyl-containing polyarylene polymer according to claim 1, characterized in that, The repeating structural units of the carboxyl-containing polyarylene polymer are selected from any of the following structural formulas: 。 8. A method for preparing a carboxyl-containing polyarylene polymer, characterized in that, Includes the following steps: Aromatic monomers and ketone monomers are dissolved in a first solvent and stirred to obtain a first mixture; At -5℃ to -5℃, an acid catalyst is added to the first mixture to carry out a polymerization reaction, resulting in a second mixture; The second mixture is poured into the second solvent, and solid substances precipitate out; The solid material was neutralized, washed with deionized water, filtered and separated, and dried to obtain a carboxyl-containing polyarylene polymer with a number average molecular weight of 30,000-500,000. The carboxyl-containing polyarylene polymer is formed from a polymer comprising repeating structural units of Formula I: Equation I; The ketone monomer is any one of the following: i. Monomers containing R1 substituents and monomers containing R2 substituents; ii. Monomers containing R2 substituents; R1 is a 2-carbonylindole ring group without carboxyl substitution; R2 is a 2-carbonylindole cyclic group with carboxyl substitution; x represents the degree of functionalization, 0 <x≤1。 9. The preparation method according to claim 8, characterized in that, The first solvent includes at least one of dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; The second solvent includes at least one of methanol, ethanol, and water; The acid catalyst includes at least one of trifluoromethanesulfonic acid and methanesulfonic acid.

10. The preparation method according to claim 8, characterized in that, When adding the acid catalyst to the first mixture, an acidity regulator is also added. The acidity regulator includes at least one of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid. The volume ratio of the acid catalyst to the acidity regulator is (0.9-10):

1.

11. The preparation method according to claim 8, characterized in that, The molar ratio of the aromatic monomer to the ketone monomer is 1:(1.1-1.3), and the volume ratio of the first solvent to the acid catalyst is 1:(3-6).

12. The preparation method according to claim 11, characterized in that, When the monomers include monomers containing R1 substituents and monomers containing R2 substituents, the molar ratio of the monomers containing R1 substituents to the monomers containing R2 substituents is 0.008-120.

13. An ion-solventized membrane, characterized in that, Includes the carboxyl-containing polyarylene polymers as described in any one of claims 1-7.

14. A method for preparing an ion-solvated film as described in claim 13, characterized in that, Includes the following steps: The carboxyl-containing polyarylene polymer is dissolved in an organic solvent to form a uniform casting solution; The casting solution is poured onto a substrate and dried to remove the solvent to form a self-supporting film. The self-supporting membrane was demolded in water to obtain an ion-solventized membrane; The organic solvent includes at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide; The mass concentration of the casting solution is 0.05-0.10 g / mL; The thickness of the ion-solventized film is 20-120 μm.

15. The application of the ion solvation membrane as described in claim 13 in water electrolysis for hydrogen production or in alkaline fuel cells.

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