Cross-linked polymer, ion exchange membrane and preparation and electrochemical application of cross-linked polymer and ion exchange membrane

Abstract

The invention discloses a cross-linked polymer and application thereof in an ion exchange membrane, and belongs to the technical field of polymer materials. The cross-linked polymer has a structure as shown in # imgabs 0 # formula I. The preparation method adopts a two-stage process: in the first stage, an intermediate is synthesized through palladium-catalyzed coupling reaction, and in the second stage, a three-dimensional network structure is formed through acid-catalyzed crosslinking. The obtained polymer has a highly conjugated pi system, the mechanical strength is enhanced through chemical crosslinking, and meanwhile, the excellent conductivity is achieved by optimizing ion group distribution. The material can be prepared into an anion exchange membrane, is coated into a membrane through a roll-to-roll process, shows excellent chemical stability and durability in a fuel cell, a super capacitor and a water electrolysis device, is particularly suitable for a 3.5 MPa high-voltage electrolysis environment, and is free of leakage when running for 1000 hours.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a cross-linked polymer, an ion exchange membrane, and preparation and electrochemical application thereof. Background Art

[0002] In the field of electrochemistry, ion exchange membranes are core components whose performance directly impacts the efficiency and stability of fuel cells, supercapacitors, organic flow batteries, and water electrolysis devices. However, existing ion exchange membranes suffer from numerous deficiencies, severely hindering further improvements in the performance of electrochemical devices.

[0003] First, existing ion exchange membranes generally have low mechanical strength. Under high current density or high-voltage operating conditions, the membrane material is prone to deformation or rupture, leading to device failure. For example, certain sulfonated polymer-based proton exchange membranes, while offering high ionic conductivity, are prone to swelling and rupture over long periods of use due to insufficient mechanical strength, compromising stable device operation.

[0004] Secondly, the chemical stability of existing ion exchange membranes needs to be improved. Many membrane materials are susceptible to chemical degradation in strong acidic, alkaline, or oxidizing environments. For example, traditional anion exchange membranes are susceptible to nucleophilic attack at high pH values, which damages the membrane's chemical structure and shortens its service life.

[0005] Furthermore, the ionic conductivity of existing ion exchange membranes is insufficient to meet the demands of high-power-density electrochemical devices. Many membrane materials lack efficient ion transport pathways, hindering ion migration and limiting device efficiency. For example, certain polystyrene-based ion exchange membranes, due to weak inter-molecular interactions and low ion transport efficiency, struggle to meet the requirements of high-performance electrochemical devices.

[0006] Furthermore, existing ion exchange membranes suffer from poor dimensional stability. During water absorption or dehydration, the membrane material undergoes significant volume changes, compromising its structural integrity and performance consistency. For example, certain polyvinyl alcohol-based ion exchange membranes exhibit poor dimensional stability under varying humidity conditions, impacting the long-term stability of the device.

[0007] Finally, existing ion exchange membranes lack adequate solvent and high-temperature resistance. Many membrane materials swell or degrade easily in high-temperature or solvent environments, leading to performance degradation. For example, certain polyimide-based ion exchange membranes experience a significant decrease in mechanical strength and chemical stability at high temperatures, making them difficult to meet the requirements of high-temperature electrochemical devices.

[0008] In summary, existing ion exchange membranes have numerous deficiencies in mechanical strength, chemical stability, ionic conductivity, dimensional stability, solvent resistance, and high-temperature resistance, severely hindering the performance of electrochemical devices. Therefore, developing an ion exchange membrane with excellent comprehensive performance is of great significance for promoting the development of the electrochemical field. Summary of the Invention

[0009] The first objective of the present invention is to address the deficiencies of the prior art and provide a cross-linked polymer having a highly conjugated π system. The polymer utilizes a larger planar conjugated structure to enhance the interaction between polymer skeletons, and then simultaneously improves ionic conductivity and mechanical strength by adjusting the ion concentration on the side chains.

[0010] To achieve the above object, the technical solution adopted by the present invention is: a cross-linked polymer comprising a structure shown in the following formula I:

[0011] Formula I;

[0012] In formula I, n is an integer from 1 to 2000;

[0013] R1 is selected from the group consisting of hydrogen, deuterium, C1-C5 alkyl, C6-C 10 Aryl, C1-C5 deuterated alkyl;

[0014] R2 is an ionic group, and its structure is , among which is the linking site;

[0015] Among them Select one of the following structural fragments:

[0016] 、 、 、 or ;

[0017] Among them Select one of the following structural fragments: 、 、 、 、 、 or ;

[0018] Wherein X1 is selected from: 0-20;

[0019] Wherein X2 is selected from: 1-9.

[0020] Furthermore, the C1-C5 alkyl group is selected from: methyl and tert-butyl.

[0021] Furthermore, the C1-C5 deuterated alkyl group is selected from: deuterated methyl group and deuterated tert-butyl group.

[0022] Furthermore, the C6-C 10 The aryl group is selected from the group consisting of phenyl, naphthyl, and anthracenyl.

[0023] Furthermore, X1 is selected from the group consisting of: 0, 1, 2, 3, 4, and 5.

[0024] Furthermore, X2 is selected from: 1, 2, 3, 4.

[0025] Furthermore, n is an integer of 200-550.

[0026] Furthermore, the cross-linked polymer is selected from one of the following structures:

[0027]

[0028] Among them Selected from: 、 or .

[0029] Furthermore, the synthesis method of the cross-linked polymer is divided into a first stage and a second stage:

[0030] Phase 1:

[0031] ;

[0032] P1-1: Under nitrogen protection, raw materials 1 and 2 were dissolved in toluene solution, and sodium tert-butoxide, tris(dibenzylideneacetone)dipalladium, and tri-tert-butylphosphine were added, stirred evenly, heated to 120°C, and refluxed for 12 hours; after the reaction was completed, the temperature was slightly lowered, and the product was filtered through diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; the product was dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was rinsed with petroleum ether several times and dried in a 60°C oven for 7 hours to obtain intermediate 1.

[0033] P1-2: NBS was added to a DCM solution of Intermediate 1. The mixture was stirred at 25°C for 16 hours. After the reaction was complete, the mixture was filtered and washed with a saturated aqueous NaHCO solution. The organic phase was washed with brine, dried over anhydrous MgSO, filtered, and concentrated in vacuo. The residue was triturated with DCM / hexane (1 / 5) to provide Intermediate 2.

[0034] P1-3: Under a nitrogen atmosphere, intermediate 2, raw material 3, and anhydrous potassium carbonate were added to the phase system in sequence, dissolved in a mixed solution of toluene, ethanol, and water (volume ratio 2:1:1), and nitrogen was replaced twice. Under nitrogen protection, tetrakis(triphenylphosphine)palladium was added to the phase system, and nitrogen was replaced twice. The reaction was heated to 75°C and refluxed for 10 hours. The heating was turned off, and the mixture was cooled to room temperature and allowed to stand for separation. The aqueous phase was extracted twice with ethyl acetate, and the organic phases were combined, washed three times with water, spin-dried, and subjected to column chromatography. A mixture of petroleum ether and dichloromethane was used as an eluent to obtain the first-stage product.

[0035] Phase 2:

[0036] ;

[0037] P2-1: The first stage product and raw material 4 are placed in a two-necked round-bottom flask and dichloromethane is added; mechanical stirring is performed to dissolve at room temperature, the reaction system is cooled to 0°C, and a trifluoromethanesulfonic acid / trifluoroacetic acid mixed solution (1:1) is slowly added dropwise. After the addition is complete, the mixture is stirred at 0°C for 10 minutes, and the reaction system is moved to a 30°C water bath. After the system temperature reaches 30°C, the molecular weight growth is detected by gel chromatography every half an hour. When the average molecular weight reaches the KDa corresponding to the corresponding n value, the reaction solution is poured into a 0°C 1:1 methanol / water solution to precipitate a solid. The solid is collected, washed with deionized water, dried, and crushed to obtain intermediate 3.

[0038] P2-2: Dissolve intermediate 3 in tetrahydrofuran in a three-necked round-bottom flask, add starting material 5, and protect the reaction system with nitrogen. Reflux the reaction system at 60°C for 72 hours. When the reaction becomes turbid, add ethanol. TLC confirms complete consumption of the methylimidazole. Pour the reaction system into anhydrous ether to obtain a flocculent precipitate. After drying, rinse the precipitate with water three times for 24 hours each time, dry it, and pulverize it to obtain intermediate 4.

[0039] P2-3: Dissolve intermediate 4 in a 1:1 tetrahydrofuran-methanol solution, filter (0.2 μm filter), and spread the solution on a flat PTFE plate (25 cm 2 ), heat the surface to 50°C, soak the membrane in water after the solvent has completely evaporated (about 24 hours), roll up the membrane material and place it in a round container, add 1M NaCl solution, and exchange it on a shaker at room temperature for 72 hours, replacing the NaCl solution every 24 hours. After the exchange is completed, rinse with deionized water until the ion conductivity of the washing solution is less than 3μS / cm. 1Cl membrane material is obtained. Use the same method to use 1M NaOH as the exchange liquid to obtain 1OH membrane. Use 1MKHCO3 as the exchange liquid to obtain 1KHCO3 membrane material.

[0040] The invention discloses an application of a cross-linked polymer in an ion exchange membrane.

[0041] Furthermore, the ion exchange membrane is an anion exchange membrane.

[0042] Furthermore, the ion exchange membrane is prepared by the following method: a cross-linked polymer is dissolved in an organic solvent to prepare a slurry, which is then coated on a substrate by a roll-to-roll process, screen printing or doctor blade casting. The organic solvent in the slurry is evaporated by drying, so that the cross-linked polymer is solidified into a film on the surface of the substrate, and the anion exchange membrane is obtained by peeling off.

[0043] Furthermore, the ion exchange membrane is used in electrochemistry.

[0044] A cross-linked polymer is used in an ion exchange membrane. The applications of the ion exchange membrane include: preparing fuel cells, preparing supercapacitors, preparing organic liquid flow batteries, electrolyzing water, electrolyzing CO2, electrolyzing CO, CO2 purification, heavy metal separation, electrically driven CO2 enrichment, lithium salt recovery, and serving as a metal-air battery separator.

[0045] The advantages of the cross-linked polymer as an ion exchange membrane in electrochemistry mainly come from its unique three-dimensional network structure and highly conjugated π system. This structure connects the polymer chains into a stable network through chemical crosslinking points, significantly enhancing the mechanical strength, enabling it to withstand large tensile and compressive stresses, and ensuring stability under high current density or high voltage conditions. At the same time, the highly conjugated π system improves chemical stability by enhancing the interaction between the molecular chains, and exhibits excellent corrosion resistance in strong acid, strong base or oxidizing environments. In addition, the ionic groups on the side chains provide efficient transmission channels for ions. By optimizing the length, density and distribution of the side chains, the ionic conductivity can be significantly improved, thereby improving the efficiency of the electrochemical device.

[0046] The three-dimensional network structure of the cross-linked polymer also provides good dimensional stability, limits the free movement of the polymer chains, and makes it less likely to undergo significant volume changes during water absorption or dehydration, thereby ensuring the structural integrity and performance consistency of the membrane. Regulation of the cross-linking density can further enhance the solvent resistance and high temperature resistance of the polymer, making it stable in high temperature or solvent environments. In addition, the intermolecular interactions of the cross-linked polymer (such as van der Waals forces and π-π stacking) enhance its durability, ensuring stable performance during long-term use. The flexibility of chemical design enables cross-linked polymers to adapt to different electrochemical application scenarios, such as fuel cells, water electrolysis, and supercapacitors, by adjusting the side chain ionic groups, cross-linking density, and main chain chemical composition.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. Excellent ion conductivity: The present invention enhances the interaction between molecular chains by designing a cross-linked polymer with a highly conjugated π system, while optimizing the length, density and distribution of the side chain ionic groups, thereby significantly improving the ion transmission efficiency. At 60 ° C, Cl - 、HCO3 - and OH - The ionic conductivity of the materials reaches over 80 mS / cm, which is much higher than that of traditional materials, providing efficient ion transport channels for electrochemical devices.

[0049] 2. Excellent mechanical strength: Chemical crosslinking connects polymer chains into a stable three-dimensional network structure, significantly enhancing mechanical strength. The tensile strength can reach 58.73 MPa, ensuring the stability of the membrane material under high current density or high voltage conditions, meeting the stringent mechanical performance requirements of electrochemical devices.

[0050] 3. Excellent chemical stability and durability: The highly conjugated π system and chemical cross-linking structure of the cross-linked polymer significantly enhance its chemical stability, demonstrating excellent corrosion resistance in strong acidic, alkaline, or oxidizing environments. Furthermore, the cross-linking structure restricts the free movement of the polymer chains, making it less likely to undergo significant volume changes during water absorption or dehydration, thus ensuring the structural integrity and performance consistency of the membrane.

[0051] 4. Broad Electrochemical Application Adaptability: By adjusting the side chain ionic groups, crosslinking density, and main chain chemical composition, the crosslinked polymers of this invention can be adapted to a variety of electrochemical applications, including fuel cells, supercapacitors, organic flow batteries, water electrolysis, and CO2 electrolysis. Their flexible chemical design enables them to exhibit excellent performance in diverse applications. DETAILED DESCRIPTION

[0052] The technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0053] The NBS of the present invention is N-bromosuccinimide, DCM is dichloromethane, MgSO4 is magnesium sulfate, NaHCO3 is sodium bicarbonate, KDa is thousand relative molecular mass, TLC is thin layer chromatography, PTFE is polytetrafluoroethylene, NaCl is sodium chloride, KHCO3 is potassium bicarbonate, NaOH is sodium hydroxide, 1 HNMR is hydrogen nuclear magnetic resonance spectroscopy. The materials and reagents involved in the present invention are all purchased from the market.

[0054] Example 1-1

[0055] ;

[0056] P1-1: Under nitrogen protection, raw material 1 (30.00 g) and raw material 2 (117.07 g) were dissolved in toluene (500 ml) solution, and sodium tert-butoxide (135.83 g), tris(dibenzylideneacetone)dipalladium (5.18 g), and tri-tert-butylphosphine (6.86 g) were added, stirred evenly, heated to 120°C, and refluxed for 12 hours; after the reaction was completed, the temperature was slightly lowered, and diatomaceous earth was used for filtration to remove salt and catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. The aqueous phase was then extracted with ethyl acetate; after the organic phases were combined, they were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; dissolved in petroleum ether / ethanol, recrystallized, filtered, and the filter cake was rinsed with petroleum ether several times and dried in a 60°C oven for 7 hours to obtain intermediate 1 (74.57 g, 73.6% inclusion rate, 99.8% purity by HPLC).

[0057] Intermediate 1 ( 1 HNMR (400 Hz, deuterated chloroform): δ 6.87 (2H, dt, J = 2.1, 0.5 Hz), 7.28 (2H, m, J = 8.2, 7.6, 1.6, 0.5 Hz), 7.60-7.99 (10H, 7.68 (m, J = 8.3, 7.6, 1.5, 0.5 Hz), 7.74 (m, J = 2.0, 1.8, 0.4 Hz), 7.81(dd,J=2.1,0.5Hz),7.91(m,J=8.3,2.0,1.6,0.4Hz),7.93(m,J=8.1,1.8,0.5H z)),8.06-8.25(4H,8.12(m,J=8.2,1.8,1.5,0.5Hz),8.19(m,J=8.1,1.8,0.4Hz)).

[0058] P1-2: NBS (92.57 g) was added to a solution of Intermediate 1 (74.57 g) in DCM (800 ml). The mixture was stirred at 25°C for 16 hours. After the reaction, the mixture was filtered and washed with saturated aqueous NaHCO3. The organic phase was washed with brine, dried over anhydrous MgSO4, filtered, and concentrated in vacuo. The residue was triturated with 300 ml of a 1 / 5 DCM / hexane solution to afford Intermediate 2 (86.71 g, 80.7% yield, 99.7% purity by HPLC).

[0059] Intermediate 2 1HNMR (400 Hz, deuterated chloroform): δ7.42 (2H, m, J=7.9, 6.5, 1.5, 0.5 Hz), 7.56-7.79 (4H, 7.63 (m, J=8.1, 6.5, 1.6, 0.4 Hz), 7.74 (m, J=2.3, 2.0, 0.4 Hz)), 7.83-7.97 (4H, 7.89 (m, J=8.1, 2.3, 0.5 Hz), 7.90 (m, J=8.1, 2.0, 1.5, 0.5 Hz)), 8.01-8.17 (6H, 8.07 (m, J=8.1, 2.1, 0.5 Hz), 8.10 (m, J=7.9, 2.1, 1.6, 0.5 Hz), 8.12 (s)).

[0060] P1-3: Under a nitrogen atmosphere, intermediate 2 (86.71 g), raw material 3 (45.06 g), and anhydrous potassium carbonate (116.07 g) were added to the phase system in sequence, dissolved in 1000 ml of a mixed solution of toluene, ethanol, and water (volume ratio 2:1:1), and nitrogen was replaced twice. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (5.82 g) was added to the phase system, and nitrogen was replaced twice. The mixture was heated to 75°C and refluxed for 10 hours. The heating was turned off, the mixture was cooled to room temperature, and the mixture was allowed to stand for separation. The aqueous phase was extracted twice with ethyl acetate, the organic phases were combined, washed three times with water, spin-dried, and subjected to column chromatography using a mixture of petroleum ether and dichloromethane as an eluent to obtain the first-stage product 1 (62.73 g, 73.1%, HPLC showed a purity of 99.9%).

[0061] The first stage product 1 1 HNMR (400 Hz, deuterated chloroform): δ7.30 (2H, m, J = 7.9, 5.1, 1.7, 0.4 Hz), 7.47-7.63 (8H, 7.54 (m, J = 6.4, 1.9, 1.1 Hz), 7.55 (m, J = 7.6, 6.4, 1.7, 0.4 Hz), 7.56 (m, J = 7.9, 7.1, 1.7, 0.4 Hz)), 7.81-7.96 (6H, 7.87 (m, J = 7 .6,1.5,0.4Hz),7.90(m,J=8.5,2.0,0.5Hz)),8.11(2H,m,J=7.1,2.0,1.7,0.5Hz),8.19-8.43(6H, 8.25(m,J=2.0,0.5Hz),8.30(m,J=5.1,2.0,1.7,0.5Hz),8.37(m,J=8.5,2.0,0.5Hz)),9.13(2H,s).

[0062] Example 1-2

[0063] Referring to the preparation method of Example 1-1, the raw material 3 was replaced by: , the rest of the feed ratio, post-treatment, etc. remain unchanged, Synthesis Example 1-2: ,

[0064] Example 1-2 1 HNMR (400 Hz, deuterated chloroform): δ1.63 (18H, s), 7.21 (4H, m, J = 7.0, 1.6, 0.5 Hz), 7.40 (2H, m, J = 7.9, 6.8, 1.6, 0.4 Hz), 7.57 (2H, m, J = 7.9, 7.1, 1.7, 0.4 Hz), 7.80-7.96 (6H, 7.86 (m, J = 7.0, 2.0, 0.5 Hz ),7.90(m,J=8.1,2.0,0.5Hz)),8.04(2H,m,J=7.1,2.0,1.6,0.5Hz),8.17-8.37(6H,8.24(m ,J=6.8,1.9,1.7,0.5Hz),8.23(m,J=2.0,0.5Hz),8.31(m,J=8.1,1.9,0.5Hz)),9.07(2H,s).

[0065] Examples 1-3

[0066] Referring to the preparation method of Example 1-1, the raw material 3 was replaced by: , the rest of the feed ratio, post-treatment, etc. remain unchanged, Synthesis Examples 1-3: ,

[0067] Examples 1-3 1 HNMR (400 Hz, deuterated chloroform): δ7.21 (4H, m, J = 7.0, 1.6, 0.5 Hz), 7.40 (2H, m, J = 7.9, 6.8, 1.6, 0.4 Hz), 7.57 (2H, m, J = 7.9, 7.1, 1.7, 0.4 Hz), 7.80-7.96 (6H, 7.86 (m, J = 7.0, 2.0, 0.5 Hz), 7.90 (m,J=8.1,2.0,0.5Hz)),8.04(2H,m,J=7.1,2.0,1.6,0.5Hz),8.17-8.37(6H,8.24(m,J= 6.8,1.9,1.7,0.5Hz),8.23(m,J=2.0,0.5Hz),8.31(m,J=8.1,1.9,0.5Hz)),9.07(2H,s).

[0068] Example 1

[0069] Preparation of cross-linked polymer 1:

[0070] ;

[0071] P2-1: The first-stage product 1 (30 g) and 4-bromo-1,1,1-trifluoro-2-butanone (13 g) were placed in a two-necked round-bottom flask, and dichloromethane (60 mL) was added. Dissolved by mechanical stirring at room temperature. The reaction system was cooled to 0°C, and a trifluoromethanesulfonic acid / trifluoroacetic acid mixture (1:1, 60 g) was slowly added dropwise. After the addition was complete, the mixture was stirred at 0°C for 10 minutes. The reaction system was then transferred to a 30°C water bath. After the temperature reached 30°C, the molecular weight was monitored by gel permeation chromatography every half hour. When the average molecular weight reached 142 kDa, the reaction solution was poured into 800 mL of cold 1:1 methanol / water solution to precipitate a solid. The solid was collected, washed with deionized water, dried, and crushed to obtain intermediate 3 (36.60 g).

[0072] Intermediate 3 1 HNMR (400 Hz, deuterated chloroform): δ 2.05 (2H, m, J = 7.2, 7.0 Hz), 2.32 (2H, t, J = 7.2 Hz), 3.21 (2H, t, J = 7.0 Hz), 7.41-7.68 (8H, 7.47 (m, J = 8.4, 1.8, 0.5 Hz), 7.51 (m, J = 6.4, 1.8, 1.1 Hz), 7.51 ( m,J=6.4,1.8,1.1Hz),7.55(m,J=7.6,6.4,1.7,0.5Hz),7.55(m,J=7.6,6.4,1.7,0.5Hz ),7.62(m,J=5.1,1.7,0.5Hz)),7.71-8.04(9H,7.76(m,J=2.0,0.5Hz),7.86(m,J=7.6, 1.5,0.5Hz),7.86(m,J=7.6,1.5,0.5Hz),7.89(m,J=8.3,2.0,0.5Hz),7.89(m,J=2.0,1 .7,0.5Hz),7.90(mJ=8.3,2.0,0.5Hz),7.98(m,J=8.4,1.9,0.5Hz)),8.10-8.49(5H,8. 16(tt,J=1.7,0.5Hz),8.25(m,J=5.1,1.9,0.5Hz),8.31(m,J=8.3,1.9,0.5Hz),8.33(m ,J=8.3,1.9,0.5Hz),8.43(m,J=2.0,1.8,0.5Hz)),9.06-9.17(2H,9.11(s),9.12(s)).

[0073] P2-2: Dissolve intermediate 3 (10 g) in 200 mL of tetrahydrofuran in a three-necked round-bottom flask, add starting material 5 (2.63 g), and protect the reaction system with nitrogen. Reflux the reaction system at 60°C for 72 hours. When the reaction becomes turbid, add 100 mL of ethanol. TLC confirms complete consumption of the methylimidazole. Pour the reaction system into 2 L of anhydrous ether to obtain a flocculent precipitate. After drying, rinse the precipitate with water three times for 24 hours each time, dry it, and pulverize to obtain intermediate 4 (9.81 g).

[0074] Intermediate 4 11H NMR (400 Hz, chloroform-d): δ 1.41 - 2.05 (24H, 1.48 (m, J = 13.8, 2.8 Hz), 1.48 (m, J = 13.8, 2.8 Hz), 1.57 (m, J = 13.8, 10.3, 6.5, 2.8 Hz), 1.57 (m, J = 13.8, 10.3, 6.5, 2.8 Hz), 1.58 (m, J = 14.7, 2.8 Hz), 1.58 (m, J = 14.7, 2.8 Hz), 1.62 (m, J = 7.4, 7.1 Hz), 1.62 (m, J = 7.4, 7.1 Hz), 1.67 (m, J = 14.7, 10.3, 2.8 Hz), 1.67 (m, J = 14.7, 10.3, 2.8 Hz), 1.83 (m, J = 11.8, 10.3, 2.8 Hz), 1.83 (m, J = 11.8, 10.3, 2.8 Hz), 1.83 (m, J = 11.8, 10.3, 2.8 Hz), 1.83 (m, J = 11.8, 10.3, 2.8 Hz), 1.94 (tt, J = 7.8, 7.4 Hz), 1.94 (tt, J = 7.8, 7.4 Hz), 1.98 (m, J = 11.8, 2.8 Hz), 1.98 (m, J = 11.8, 2.8 Hz), 1.98 (m, J = 11.8, 2.8 Hz), 1.98 (dq, J = 11.8, 2.8 Hz)), 2.77 - 2.87 (3H, 2.82 (s), 2.82 (s)), 3.13 - 3.25 (2H, 3.19 (t, J = 7.8 Hz), 3.19 (t, J = 7.8 Hz)), 3.66 (1H, d, J = 5.4 Hz), 4.23 - 4.42 (3H, 4.30 (tt, J = 10.3, 2.8 Hz), 4.30 (tt, J = 10.3, 2.8 Hz), 4.36 (td, J = 7.1, 5.4 Hz)), 7.35 (1H, ddd, J = 8.4, 1.8, 0.5 Hz), 7.46 - 7.75 (9H, 7.53 (m, J = 7.9, 6.2, 1.7, 0.4 Hz), 7.53 (m, J = 7.9, 6.2, 1.7, 0.4 Hz), 7.54 (m, J = 8.0, 6.3, 1.7, 0.5 Hz), 7.54 (m, J = 8.0, 6.3, 1.7, 0.5 Hz), 7.54 (m, J = 6.3, 1.7, 1.1 Hz), 7.54 (m, J = 6.3, 1.7, 1.1 Hz), 7.61 (m, J = 7.9, 1.4, 1.1, 0.5 Hz), 7.61 (m, J = 7.9, 1.4, 1.1, 0.5Hz),7.69(ddd, J =6.3,1.7,0.4Hz)),7.80-8.30(12H,7.86(ddd, J =8.3,2.0,0.5Hz),7.91(m, J =7.6,2.0,0.5Hz),7.96(m, J=8.4,2.0,0.5Hz),8.03(m, J =6.3,2.0,0.5Hz),8.06(m, J =8.0,1.7,1.4,0.4Hz),8.06(m, J =8.0,1.7,1.4,0.4Hz),8.10(ddt, J =8.3,2.0,0.5Hz),8.10(m, J =2.0,1.8,0.5Hz),8.13(m, J =7.6,2.0,0.5Hz),8.22(m, J =2.0,0.5Hz),8.22(m, J =2.0,0.5Hz),8.24(m, J =2.0,1.7,0.5Hz)),9.00-9.15(2H,9.05(s),9.10(s)). .

[0075] P2-3: Dissolve 1 g of intermediate 4 in 36 mL of 1:1 tetrahydrofuran-methanol solution, filter (0.2 μm filter), and spread the solution on a flat PTFE plate (25 cm 2 ), heat the surface to 50°C. After the solvent has completely evaporated (approximately 24 hours), soak the membrane in water and remove it. Roll the membrane material into a 20 cm high circular container, add 100 mL of 1 M NaOH solution, and exchange it on a shaker at room temperature for 72 hours, replacing the NaOH solution every 24 hours. After the exchange is complete, rinse with deionized water until the ionic conductivity of the washing solution is less than 3 μS / cm to obtain a 1OH membrane. Use the same method to use 1 M NaCl as the exchange solution to obtain a 1 Cl membrane material. Use the same method to use 1 M KHCO3 as the exchange solution to obtain a 1 KHCO3 membrane material (1A). Elemental analysis of the 1A membrane material shows a Br content of less than 0.1 wt%.

[0076] Example 2

[0077] Preparation of cross-linked polymer 2: Referring to the preparation method of Example 1, the first-stage product 1 in Example 1 was replaced with the compound prepared in Example 1-2, and the rest of the feed ratio, post-treatment, etc. remained unchanged. The structure of intermediate 4 in Preparation Example 2 is: .

[0078] Example 3

[0079] Preparation of cross-linked polymer 3: Referring to the preparation method of Example 1, the first-stage product 1 in Example 1 was replaced with the compound prepared in Examples 1-3, and the rest of the feed ratios, post-treatments, etc. remained unchanged. The structure of intermediate 4 in Preparation Example 3 is: .

[0080] Example 4

[0081] Preparation of cross-linked polymer 9: Referring to the preparation method of Example 1, the first stage product 1 in Example 1 was replaced by the compound prepared in Example 1-2, and the raw material 5 was replaced by , the rest of the feed ratio, post-treatment, etc. remain unchanged. The structure of the intermediate 4 in Preparation Example 4 is: .

[0082] Example 5

[0083] Preparation of cross-linked polymer 10: Referring to the preparation method of Example 1, the first stage product 1 in Example 1 was replaced by the compound prepared in Example 1-2, and the raw material 5 was replaced by , the rest of the feed ratio, post-treatment, etc. remain unchanged. The structure of the intermediate 4 in Preparation Example 5 is: .

[0084] Example 6

[0085] Preparation of cross-linked polymer 11: Referring to the preparation method of Example 1, the first stage product 1 in Example 1 was replaced by the compound prepared in Example 1-3, and the raw material 5 was replaced by , the rest of the feed ratio, post-treatment, etc. remain unchanged. The structure of the intermediate 4 in Preparation Example 6 is: .

[0086] Test Example 1:

[0087] Comparative Example 1.

[0088] The polymers prepared in Examples 1-6 and Comparative Example 1 were subjected to performance tests using the following methods:

[0089] AC impedance test:

[0090] Electrochemical impedance spectroscopy (EIS) tests were performed on the polymers prepared in Examples 1-6 and Comparative Example 1 using an electrochemical workstation. The membrane sample (4 cm long, 1 cm wide) was properly fixed in a custom electrochemical test cell (4 electrodes, platinum as the electrode material), ensuring close contact between the membrane and the test cell electrode system. Before the test, the test solution (such as an electrolyte solution of a specific concentration) was injected into the test cell to fully soak the membrane sample. If the test temperature was not stable at room temperature, the sample was allowed to equilibrate in the electrolyte for at least 30 minutes to allow the sample to reach the test temperature. The test parameters of the electrochemical workstation were set, with the scanning frequency range set to 1*106 Hz to 0.1 Hz, the AC excitation signal amplitude to 2 sec, and the voltage to 100 mV. The impedance value was obtained when the phase angle was closest to 0°, and the ionic conductivity was calculated based on the sample size and thickness.

[0091] Tensile strength test:

[0092] The tensile strength of membrane samples was tested using a universal tensile machine. Membrane samples were precisely cut into standard dumbbell-shaped specimens, with dimensions strictly conforming to the national standard GB / T 1040.3-2 (length 150 mm, width 20 mm, thickness 20-60 μm). The specimens were mounted between the upper and lower clamps of the universal tensile machine at a rate of 50 mm / min. Upon initiation of the test, the tensile force acting on the specimen and the corresponding elongation were monitored and recorded in real time until the specimen fractured. The tensile strength of the membrane was calculated based on the recorded data (the tensile force at fracture divided by the original cross-sectional area of the specimen).

[0093] The material performance test results are shown in Table 1 below: .

[0094] Table 1 Test results of mechanical strength and ionic conductivity of the preferred structure.

[0095] The data in Table 1 show that the cross-linked polymers prepared in Examples 1-6 have - 、HCO3 - and OH - The ionic conductivity (at 60°C) of Example 2 is significantly higher than that of Comparative Example 1 (traditional material). - The conductivity is the highest (95.24 mS / cm), indicating that its ion transmission efficiency is excellent; and in terms of tensile strength, although all examples (44.37-58.73 MPa) are lower than that of comparative example 1 (89.12 MPa), they still maintain high mechanical stability, indicating that the design of the cross-linked structure has achieved an optimal balance between ion conduction and mechanical properties. For example, HCO3 in Example 2 -The best overall performance was achieved in terms of conductivity (90.57 mS / cm) and tensile strength (58.73 MPa), reflecting the synergistic effect of the three-dimensional conjugated network and the side chain ionic groups, which not only enhanced the intermolecular interaction and increased the strength, but also maintained the high efficiency of the ion channel through controllable cross-linking density.

[0096] Application Example 1

[0097] The film prepared from polymer 1 obtained in Example 1 was used to perform an anion exchange membrane water electrolysis test (X=OH during electrolysis):

[0098] Cut to the appropriate size (usually 5×5cm 2 ) of the circular PTFE gasket, electrode and the anion exchange membrane that has been exchanged; fix the current collecting plate to the cathode flow channel plate with bolts through the positioning holes and put it into the fixture; place the PTFE on the flow channel area, and place the cathode electrode in the hollow space in the middle; pass the anode flow channel plate and the current collecting plate through the positioning holes to cover the PTFE, tighten the entire test cell with nuts and bolts through the positioning holes, and adjust the torque of the test cell with a torque wrench; connect the installed cell to the corresponding inlet and outlet water pipes according to the anode and cathode, turn on the circulation pump, set the flow rate, and circulate the heated electrolyte into the system; connect the positive and negative poles of the power supply and the voltage, current and temperature detection device to the test cell, set the program and current size, turn on the pump circulation at the same time, heat the system to the corresponding temperature, turn on the power and the corresponding program, start the electrolysis experiment, and collect operating parameters such as temperature, current, and voltage.

[0099] Electrolysis tests used NiFeSOx oxide as a hydrogen evolution catalyst attached to a nickel mesh, and NiMo as an oxygen evolution catalyst attached to a nickel mesh. Operating conditions were 1 M KOH, 60°C. After 1000 hours of testing, the backpressure valve was opened to bring the pressure at the hydrogen production end to 3.5 MPa. The system operated continuously for 200 hours without any gas or liquid leakage. These electrolytic cell tests demonstrated the chemical and mechanical stability of the membrane of this invention, as well as its excellent electrolytic performance.

[0100] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cross-linked polymer, characterized in that Contains the structure shown in the following formula I: Formula I; In formula I, n is an integer from 1 to 2000; R1 is selected from the group consisting of hydrogen, deuterium, C1-C5 alkyl, C6-C 10 Aryl, C1-C5 deuterated alkyl; R2 is an ionic group, and its structure is , among which is the linking site; Among them Select one of the following structural fragments: 、 、 、 or ; Among them Select one of the following structural fragments: 、 、 、 、 、 or ; Wherein X1 is selected from: 0-20; Wherein X2 is selected from: 1-9.

2. A cross-linked polymer according to claim 1, characterized in that The C1-C5 alkyl group is selected from: methyl and tert-butyl.

3. A cross-linked polymer according to claim 1, characterized in that The C1-C5 deuterated alkyl group is selected from: deuterated methyl and deuterated tert-butyl.

4. A cross-linked polymer according to claim 1, characterized in that The C6-C 10 The aryl group is selected from the group consisting of phenyl, naphthyl, and anthracenyl.

5. A cross-linked polymer according to claim 1, characterized in that The cross-linked polymer is selected from one of the following structures: ； ； ； Among them Selected from: 、 or .

6. Use of a cross-linked polymer according to any one of claims 1 to 5 in an ion exchange membrane.

7. Use of a cross-linked polymer in an ion exchange membrane according to claim 6, characterized in that: The ion exchange membrane is an anion exchange membrane.

8. Use of a cross-linked polymer according to any one of claims 6 to 7 in an ion exchange membrane, characterized in that: The ion exchange membrane is prepared by the following method: a cross-linked polymer is dissolved in an organic solvent to prepare a slurry, which is then coated on a substrate by a roll-to-roll process, screen printing, or doctor blade casting. The organic solvent in the slurry is evaporated by drying to solidify the cross-linked polymer into a film on the surface of the substrate, which is then peeled off to obtain the anion exchange membrane.

9. The use of a cross-linked polymer in an ion exchange membrane according to claim 6, characterized in that: Application of the ion exchange membrane in electrochemistry.

10. Use of a cross-linked polymer in an ion exchange membrane according to claim 6, characterized in that: The applications of the ion exchange membrane include: preparing fuel cells, preparing supercapacitors, preparing organic liquid flow batteries, electrolyzing water, electrolyzing CO2, electrolyzing CO, CO2 purification, heavy metal separation, electrically driven CO2 enrichment, lithium salt recovery, and serving as a metal-air battery separator.

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