Nitrogen-containing branched polymer, anion exchange resin, anion exchange membrane, and electrochemical device

Abstract

The present application provides a nitrogen-containing branched polymer, an anion exchange resin, an anion exchange membrane, and an electrochemical device. The nitrogen-containing branched polymer comprises a nitrogen-containing heterocyclic ring, a branched structure and an aryl, wherein the number of branching points of each branched structure is not less than 3, and the aryl is linked with the branching points of the branched structure by means of the nitrogen-containing heterocyclic ring. The molar ratio of the aryl to the branched structure in the nitrogen-containing branched polymer is A:B = 80-99:1-20. The nitrogen-containing branched polymer satisfies: PDI≤2.6, and has a weight-average molecular weight of 40,000 g / mol to 50,000 g / mol.

Description

Nitrogen-containing branched polymer, anion exchange resin, anion exchange membrane and electrochemical device

[0001] This application claims priority to the Chinese patent application No. 202411262014.0 filed on September 9, 2024 with the Chinese Patent Office, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of anion exchange membranes, in particular, to a nitrogen-containing branched polymer, an anion exchange resin, an anion exchange membrane and an electrochemical device. BACKGROUND

[0003] Trade-off effect, also known as trade-off effect, generally refers to the case of trade-off between two or more parameters. Trade-off effect shows that for the same product, when a priority is made on one performance, the other performance may be impaired, and vice versa. In the field of materials, the existence of trade-off effect constitutes an obstacle to the popularization and application of new materials.

[0004] Anion exchange membranes (AEMs) are the core components of alkaline electrochemical devices, which function to conduct OH - from the cathode to the anode of the electrochemical device, while also serving to block the direct transmission of gas and electrons between electrodes. The key property requirements of AEMs related to alkaline electrochemical devices are high ionic conductivity, low swelling, high mechanical strength and excellent alkali resistance.

[0005] In developing ideal AEMs for alkaline electrochemical devices, both the polymer backbone and the cationic group of AEMs are important design considerations. Currently, the strategy of combining a polyaromatic hydrocarbon backbone without aryl ether with a nitrogen-containing heterocycle as the cationic group of AEMs is generally adopted to improve the durability of AEMs. However, most AEMs still have a trade-off effect between ionic conductivity and structural stability. Ensuring high ionic conductivity of AEMs requires sufficient conductive groups, but the introduction of conductive groups inevitably leads to reduced structural stability and mechanical properties of the membrane material. On the other hand, to improve the mechanical stability of AMEs membranes, cross-linking methods can be used, but cross-linking operations will significantly reduce the ionic conductivity of AMEs and also reduce the toughness of the membrane to some extent, making the membrane brittle. On the other hand, there is also a trade-off effect between ionic conductivity and water absorption swelling properties. AEMs with high ionic conductivity also tend to have high water absorption swelling properties. Generally speaking, the greater the water absorption swelling of AEMs, the more abundant and wider the corresponding hydration channels, which will lead to increased hydrogen gas permeation across the membrane in practical applications, posing a major safety hazard. Technical problems

[0006] In the related art, during the improvement and development of AEMs, trade-off effects exist among different performance indicators, which seriously limits the industrialization of AEMs material systems. Technical solutions

[0007] In a first aspect, the application provides a nitrogen-containing branched polymer, the molecular structure of the nitrogen-containing branched polymer comprising a nitrogen-containing heterocycle, a branched structure and an aryl group, the number of branched points of each branched structure being not less than 3, and the aryl group being connected to the branched site of the branched structure through the nitrogen-containing heterocycle; A represents the molar proportion of the aryl group in the nitrogen-containing branched polymer, B represents the molar proportion of the branched structure in the nitrogen-containing branched polymer, and A:B = 80-99:1-20; the polydispersity index PDI of the nitrogen-containing branched polymer is ≤2.6, and the weight average molecular weight of the nitrogen-containing branched polymer is 40,000-500,000 g / mol. By keeping the content of aryl groups and branched structures in the polymer within a specific ratio range, the basic skeleton of the nitrogen-containing polymer has good structural strength and contains abundant conductive groups. Based on the basic skeleton structure of the nitrogen-containing polymer, the weight average molecular weight and the polydispersity index PDI of the polymer are controlled within a certain range, so that the structural strength of the nitrogen-containing branched polymer is further improved, and the corresponding water absorption and swelling rate is controlled at a low level. Based on this, the trade-off effect among the ionic conductivity, structural stability and water absorption and swelling characteristics of the nitrogen-containing branched polymer is alleviated. The nitrogen-containing branched polymer provided by the application can have excellent ionic conductivity and mechanical properties under the premise of achieving a low water absorption and swelling rate, and is suitable for preparing high-efficiency and stable anion exchange resins and anion exchange membranes.

[0008] In a second aspect, the application provides a preparation method of the nitrogen-containing branched polymer in the first aspect, comprising the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein monomer I is an aryl monomer, monomer II is a monomer comprising a branched structure, and monomer III is a monomer comprising a nitrogen-containing heterocycle; adding an acid catalyst to the reaction monomer mixture at a temperature of -5-0℃ to obtain a reaction liquid; S2. allowing the reaction liquid to undergo an oligomerization reaction, the reaction temperature of the oligomerization reaction being 0-10℃, and obtaining an oligomer mixture after the oligomerization reaction ends; S3. allowing the oligomer mixture to undergo a polymerization reaction, the reaction temperature of the polymerization reaction being 0-24℃; S4. separating the polymer from the product after the polymerization reaction ends, and performing acid removal treatment on the polymer, the polymer being converted into the nitrogen-containing branched polymer after the acid removal treatment.

[0009] In a third aspect, the application provides an anion exchange resin, which comprises a quaternized product of the nitrogen-containing branched polymer as in the first aspect. The anion exchange resin provided by the application can achieve low water swelling while having excellent ionic conductivity and mechanical properties, and can be used to prepare a high-efficiency and stable anion exchange membrane.

[0010] In a fourth aspect, the application provides a preparation method of the anion exchange resin as in the third aspect, comprising the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein monomer I is an aryl monomer, monomer II is a monomer comprising a branched structure, and monomer III is a monomer comprising a nitrogen-containing heterocyclic ring; adding an acid catalyst to the reaction monomer mixture at a temperature of -5℃ to 0℃ to obtain a reaction solution; S2. allowing the reaction solution to undergo an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0℃ to 10℃, and the oligomer mixture is obtained after the oligomerization reaction; S3. allowing the oligomer mixture to undergo a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0℃ to 24℃; S4. separating the polymer from the product after the polymerization reaction, and performing acid removal treatment on the polymer, wherein the polymer is converted into a nitrogen-containing branched polymer after the acid removal treatment; S5. preparing a quaternization reaction solution by adding the nitrogen-containing branched polymer and a quaternization reagent into a solvent B, and then allowing the nitrogen-containing branched polymer to undergo a quaternization reaction with the quaternization reagent, and separating the anion exchange resin from the product obtained from the quaternization reaction.

[0011] In a fifth aspect, the application provides an anion exchange membrane, which comprises the anion exchange resin as in the third aspect. The anion exchange membrane provided by the application not only has good mechanical properties but also can achieve high ionic conductivity, and when applied to an electrochemical device, can significantly improve the electrochemical performance and structural stability of the electrochemical device. In addition, due to the low water swelling rate of the anion exchange membrane, the hydration channel volume thereof can be reduced, and thus the electrochemical device using the same can maintain a low hydrogen gas transmembrane permeation rate.

[0012] In a sixth aspect, the application provides a preparation method of the anion exchange membrane in the fifth aspect, comprising the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein monomer I is an aryl monomer, monomer II is a monomer comprising a branched structure, and monomer III is a monomer comprising a nitrogen-containing heterocycle; adding an acid catalyst into the reaction monomer mixture at a temperature of -5°C to 0°C to obtain a reaction solution; S2. allowing the reaction solution to undergo an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0°C to 10°C; obtaining an oligomer mixture after the oligomerization reaction; S3. allowing the oligomer mixture to undergo a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0°C to 24°C; S4. separating a polymer from the product after the polymerization reaction, and performing an acid removal treatment on the polymer, wherein the polymer is converted into a nitrogen-containing branched polymer after the acid removal treatment; S5. preparing a quaternary ammonium reaction solution by adding the nitrogen-containing branched polymer and a quaternary ammonium reagent into a solvent B, and then allowing the nitrogen-containing branched polymer to undergo a quaternary ammonium reaction with the quaternary ammonium reagent, and separating an anion exchange resin from the product of the quaternary ammonium reaction; and S6. preparing a homogeneous solution containing the anion exchange resin in a solute, and then coating a thin film substrate with the homogeneous solution, and drying to obtain the anion exchange membrane.

[0013] In a seventh aspect, the application provides an electrochemical device comprising the anion exchange membrane in the fifth aspect. Based on the application of the anion exchange membrane provided by the application, the hydrogen in oxygen in the electrochemical device can be long-term controlled within a safe range, thereby improving the safety of the electrochemical device. In addition, the high ionic conductivity of the anion exchange membrane ensures the efficient transmission of ions in the electrochemical device, thereby improving the electrochemical performance of the electrochemical device. Advantages

[0014] The application provides a nitrogen-containing branched polymer, an anion exchange resin, an anion exchange membrane and an electrochemical device, which can relieve the trade-off effect among the ionic conductivity, structural stability and water absorption swelling characteristics of AEMs, so as to improve the ionic conductivity, structural stability and water absorption swelling rate of AEMs. BRIEF DESCRIPTION OF DRAWINGS

[0015] FIG. 1 is an ionic conductivity testing device;

[0016] FIG. 2 is a statistical diagram of the test results of the tensile strength and elongation at break of the test object of Test Example 1;

[0017] FIG. 3 is a statistical diagram of the test results of the ionic conductivity, water absorption rate and swelling rate of the test object of Test Example 1;

[0018] FIG. 4 is a statistical diagram of the test results of the hydrogen content in oxygen and polarization performance of the alkaline membrane single cell using the test object of Test Example 1;

[0019] Fig. 5 is a graph showing the tensile strength and elongation at break of the test object of Test Example 2;

[0020] Fig. 6 is a graph showing the ion conductivity, water absorption, and swelling of the test object of Test Example 2;

[0021] Fig. 7 is a graph showing the hydrogen content in oxygen and the polarization performance of the alkaline membrane single cell using the test object of Test Example 2;

[0022] Fig. 8 is a graph showing the tensile strength and elongation at break of the test object of Test Example 3;

[0023] Fig. 9 is a graph showing the ion conductivity, water absorption, and swelling of the test object of Test Example 3;

[0024] Fig. 10 is a graph showing the hydrogen content in oxygen and the polarization performance of the alkaline membrane single cell using the test object of Test Example 3;

[0025] Fig. 11 is a graph showing the tensile strength and elongation at break of the test object of Test Example 4;

[0026] Fig. 12 is a graph showing the ion conductivity, water absorption, and swelling of the test object of Test Example 4;

[0027] Fig. 13 is a graph showing the hydrogen content in oxygen and the polarization performance of the alkaline membrane single cell using the test object of Test Example 4. Embodiments of the present application

[0028] The application provides a nitrogen-containing branched polymer, the molecular structure of the nitrogen-containing branched polymer comprises a nitrogen-containing heterocycle, a branched structure and an aryl group, the number of branched points of each branched structure is not less than 3, and the aryl group is connected to the branched point of the branched structure through the nitrogen-containing heterocycle; A represents the molar proportion of the aryl group in the nitrogen-containing branched polymer, B represents the molar proportion of the branched structure in the nitrogen-containing branched polymer, A:B = 80-99:1-20; the polydispersity index PDI of the nitrogen-containing branched polymer is ≤2.6, and the weight average molecular weight of the nitrogen-containing branched polymer is 40000-500000 g / mol. By controlling the content of the aryl group and the branched structure in the polymer within a specific ratio range, the basic skeleton of the nitrogen-containing polymer has good structural strength and contains rich conductive groups, based on the basic skeleton structure of the nitrogen-containing polymer, the weight average molecular weight and the polydispersity index PDI of the polymer are controlled within a certain range, the structural strength of the nitrogen-containing branched polymer is further improved, and the corresponding water absorption swelling rate is controlled at a low level, based on this, the trade-off effect among the ion conductivity, structural stability and water absorption swelling characteristics of the nitrogen-containing branched polymer is alleviated. The nitrogen-containing branched polymer provided by the application can have excellent ion conductivity and mechanical properties under the premise of achieving a low water absorption swelling rate, and is suitable for preparing high-efficiency and stable anion exchange resins and anion exchange membranes.

[0029] In some embodiments, A represents the molar proportion of the aryl group in the nitrogen-containing branched polymer, B represents the molar proportion of the branched structure in the nitrogen-containing branched polymer, A:B = 85-95:5-15.

[0030] In some embodiments, the aryl group comprises at least one of biphenyl, terphenyl, and quaterphenyl.

[0031] In some embodiments, the branched structure comprises a benzene ring structure provided with a branched point.

[0032] In some embodiments, the branched structure comprises at least one of the following structures: a 1,3,5-triphenylbenzene structural unit, a triphenylmethane structural unit, a 9,10-benzo phenanthrene structural unit, a tetraphenylmethane structural unit, a triptycene structural unit, a 9,9-diphenylfluorene structural unit, a 9,9'-spirobifluorene structural unit, a 9,9'-bifluorene structural unit, a 9,9'-biscarbazole structural unit, a 4,4'-bis(9-carbazole)biphenyl structural unit, and a 2,2"-linked-9,9'-spirobis[9H-fluorene] structural unit.

[0033] In some embodiments, the nitrogen-containing heterocycle comprises at least one of a piperidine ring and a quinuclidine ring.

[0034] In some embodiments, the nitrogen-containing branched polymer comprises a molecular structure comprising segment I and segment II; segment I has a general structure of wherein A represents a nitrogen-containing heterocycle, Ar1 represents an aryl group, and X represents a degree of polymerization of segment I; segment II is composed of a nitrogen-containing heterocycle and a branching structure, and in segment II, the nitrogen-containing heterocycle is directly connected to a branching site of the branching structure.

[0035] In some embodiments, the nitrogen-containing branched polymer comprises a basic structural unit connected by segment I and segment II; in the basic structural unit, segment I and segment II are connected in such a way that the aryl group in segment I connects the nitrogen-containing heterocycle in segment II.

[0036] In some embodiments, in the basic structural unit, the number of segment I directly connected to each segment II is ≥ 3.

[0037] In some embodiments, the nitrogen-containing branched polymer has a weight average molecular weight of 40,000-250,000 g / mol.

[0038] In some embodiments, the nitrogen-containing branched polymer has a weight average molecular weight of 40,000-130,000 g / mol.

[0039] In some embodiments, the aryl group is a terphenyl group.

[0040] In some embodiments, the aryl group is a p-terphenyl group.

[0041] In some embodiments, the nitrogen-containing polymer comprises at least one of nitrogen-containing branched polymer A, nitrogen-containing branched polymer B, nitrogen-containing branched polymer C, nitrogen-containing branched polymer D, and nitrogen-containing branched polymer E.

[0042] The nitrogen-containing branched polymer A is

[0043] The nitrogen-containing branched polymer B is

[0044] The nitrogen-containing branched polymer C is

[0045] The nitrogen-containing branched polymer D is

[0046] The nitrogen-containing branched polymer E is

[0047] The application provides a preparation method of the nitrogen-containing branched polymer in the nitrogen-containing branched polymer embodiment, comprising the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein the monomer I is an aryl monomer, the monomer II is a monomer comprising a branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle; adding an acid catalyst into the reaction monomer mixture at a temperature of -5-0°C to obtain a reaction solution; S2. allowing the reaction solution to undergo an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0-10°C; obtaining an oligomer mixture after the oligomerization reaction; S3. allowing the oligomer mixture to undergo a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0-24°C; S4. separating the polymer from the product after the polymerization reaction, and performing an acid removal treatment on the polymer, wherein the polymer is converted into the nitrogen-containing branched polymer after the acid removal treatment.

[0048] In some embodiments, in S1, the acid catalyst is added into the reaction monomer mixture in a dropwise feeding mode, and the dropwise feeding speed is 0.3-2 mL / min.

[0049] In some embodiments, the reaction time of the oligomerization reaction is 1-5 hours, and the reaction time of the polymerization reaction is 1-15 hours.

[0050] In some embodiments, in S4, the polymer is discharged from the extruder in the form of an extrudate in a columnar shape, and the radial cross-sectional diameter of the extrudate is 0.5-2.5 mm.

[0051] In some embodiments, in S4, the extrudate is discharged into pure water or an aqueous solution, and the solute in the aqueous solution comprises at least one of potassium carbonate, sodium carbonate, sodium chloride, potassium hydroxide and calcium chloride.

[0052] The application provides an anion exchange resin, which comprises a quaternized product of the nitrogen-containing branched polymer in the nitrogen-containing branched polymer embodiment. The anion exchange resin provided by the application can achieve low water swelling, excellent ion conductivity and mechanical properties, and can be used for preparing a high-efficiency and stable anion exchange membrane.

[0053] In some embodiments, the anion exchange resin comprises at least one of anion exchange resin A, anion exchange resin B, anion exchange resin C, anion exchange resin D, anion exchange resin E, anion exchange resin F, anion exchange resin G, anion exchange resin H, anion exchange resin I, anion exchange resin J, anion exchange resin K and anion exchange resin L.

[0054] Anion exchange resin A

[0055] Anion exchange resin B

[0056] Anion exchange resin C

[0057] Anion exchange resin D

[0058] Anion exchange resin E

[0059] Anion exchange resin F

[0060] Anion exchange resin G

[0061] Anion exchange resin H

[0062] Anion exchange resin I

[0063] Anion exchange resin J

[0064] Anion exchange resin K

[0065] Anion exchange resin L

[0066] In some embodiments, the anion exchange resin comprises at least one of anion exchange resin A, anion exchange resin B, anion exchange resin C, anion exchange resin D, anion exchange resin E.

[0067] The application provides a preparation method of the anion exchange resin in the anion exchange resin embodiments, comprising the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein the monomer I is an aryl monomer, the monomer II is a monomer containing a branched structure, and the monomer III is a monomer containing a nitrogen-containing heterocyclic ring; adding an acid catalyst to the reaction monomer mixture under a temperature condition of-5℃-0℃ to obtain a reaction liquid; S2. allowing the reaction liquid to undergo an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0℃-10℃, and the oligomer mixture is obtained after the oligomerization reaction is completed; S3. allowing the oligomer mixture to undergo a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0℃-24℃; S4. separating the polymer from the product after the polymerization reaction is completed, and performing an acid removal treatment on the polymer, wherein the polymer is converted into a nitrogen-containing branched polymer after the acid removal treatment; S5. preparing a quaternary ammonium reaction liquid by adding the nitrogen-containing branched polymer and a quaternary ammonium reagent into a solvent B, and then allowing the nitrogen-containing branched polymer and the quaternary ammonium reagent to undergo a quaternary ammonium reaction, and separating the anion exchange resin from the product obtained from the quaternary ammonium reaction.

[0068] The anion exchange resin prepared by the preparation method of the anion exchange resin provided in the application can effectively improve the non-uniformity of molecular weight of branched materials with further increased branching degree, and can controllably and stably prepare the anion exchange resin of the application, and effectively improve the solubility of high-branched materials, and guarantee the excellent performance of the anion exchange resin containing branched structures.

[0069] In some embodiments, in S1, the acid catalyst is added to the reaction monomer mixture in a dropwise feeding mode, and the dropwise feeding speed is 0.3 mL / min-2 mL / min.

[0070] In some embodiments, the reaction time of the oligomerization reaction is 1 hour-5 hours, and the reaction time of the polymerization reaction is 1 hour-15 hours.

[0071] In some embodiments, the monomer I includes at least one of the following aryl monomers: (diphenyl biphenyl), (p-terphenyl), (m-terphenyl), (quaterphenyl), (1,2-diphenyl ethane).

[0072] In some embodiments, the monomer II includes at least one of the following materials:

[0073] (1,3,5-triphenyl benzene), (triphenyl methane), (9,10-benzo phenanthrene), (tetraphenyl methane), (triptycene), (9,9-diphenyl fluorene), (9,9'-spirobifluorene), (9,9'-bifluorene), (9,9'-biscarbazole), (2,2"-linked-9,9'-spirobis[9H-fluorene]), (4,4'-bis(9-carbazole) biphenyl), (9-(9H-fluoren-9-yl) anthracene), (triphenylamine).

[0074] In some embodiments, the monomer III includes at least one of piperidone monomers and quinuclidone monomers.

[0075] In some embodiments, the structure general formula of the piperidone monomer is wherein R1, R2 are independently selected from methyl, ethyl, propyl, butyl, pentyl, cyclopropyl.

[0076] In some embodiments, the quinuclidone monomer has a structure of wherein R3 is hydrogen, alkyl, alkenyl, alkynyl, or an aromatic ring.

[0077] In some embodiments, the piperidone monomer includes at least one of

[0078] the quinuclidone monomer includes at least one of

[0079] In some embodiments, the acid catalyst includes at least one of methanesulfonic acid, pentafluoropropionic acid, trifluoroacetic acid, triflic acid, heptafluorobutyric acid, with reference to the amount of monomer III as an equivalent, the amount of acid catalyst satisfies 4 eq-14 eq.

[0080] In some embodiments, the acid catalyst includes trifluoroacetic acid and triflic acid.

[0081] In some embodiments, with reference to the amount of monomer III as an equivalent, the amount of trifluoroacetic acid and triflic acid satisfies trifluoroacetic acid: triflic acid = 0.5 eq-3 eq: 3.5 eq-11 eq.

[0082] In some embodiments, in S5, the amount of nitrogen-containing branched polymer and quaternization reagent satisfies, in terms of molar ratio, nitrogen-containing branched polymer: quaternization reagent = 1:(1-3).

[0083] In some embodiments, the quaternization reagent includes at least one of methyl trifluoroacetate, methyl p-toluenesulfonate, methyl iodide, propyl bromide, ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, ethyl bromide, butyl bromide, pentyl bromide, hexyl bromide, cyclohexyl bromide, cyclopentyl bromide, cyclohexyl bromide, methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate, ethyl ethanesulfonate, but-3-yn-1-yl methanesulfonate, allyl allyl sulfonate, methyl benzenesulfonate, methyl nitrobenzenesulfonate, methyl triflate, ethyl triflate, ethyl tosylate, cyclobutyl toluene-4-sulfonate, butyl tosylate, neopentyl benzenesulfonate, tetrahydro-2H-pyran-4-yl methanesulfonate, or cyclohexyl p-toluenesulfonate.

[0084] In some embodiments, the preparation of the reaction monomer mixture includes the following operation: mixing monomer I, monomer II, and monomer III in solvent A, which is composed of at least one of dichloromethane, chloroform, or tetrahydrofuran.

[0085] In some embodiments, the reaction temperature of the quaternization reaction is 10-100℃.

[0086] In some embodiments, the reaction time of the quaternization reaction is 4-36 hours.

[0087] In some embodiments, the solvent B is composed of at least one of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, acetonitrile.

[0088] In some embodiments, the separation of the product from the quaternization reaction in S5 to obtain the anion exchange resin specifically includes the following operations: adding a precipitant to the product from the quaternization reaction, washing and drying the precipitate separated from the product, and then performing ion exchange treatment to obtain the anion exchange resin; the precipitant includes at least one of ethanol, ethyl acetate, ethylene glycol, diethyl ether, tetrahydrofuran, acetone or water.

[0089] The present application provides an anion exchange membrane, which comprises the anion exchange resin in the anion exchange resin embodiments of the present application. The anion exchange membrane provided by the present application not only has good mechanical properties but also can achieve high ionic conductivity. When the anion exchange membrane is applied to an electrochemical device, the electrochemical performance and structural stability of the electrochemical device can be significantly improved. In addition, due to the low water absorption swelling rate of the anion exchange membrane, the hydration channel volume thereof can be reduced, and thus the hydrogen gas transmembrane permeability of the electrochemical device using the anion exchange membrane can be kept low.

[0090] The present application provides a preparation method of the anion exchange membrane in the anion exchange membrane embodiments, which comprises the following operations: S1. preparing a reaction monomer mixture containing monomer I, monomer II and monomer III, wherein the monomer I is an aryl monomer, the monomer II is a monomer comprising a branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle; adding an acid catalyst to the reaction monomer mixture at a temperature of-5-0℃ to obtain a reaction solution; S2. allowing the reaction solution to undergo an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0-10℃; obtaining an oligomer mixture after the oligomerization reaction is completed; S3. allowing the oligomer mixture to undergo a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0-24℃; S4. separating a polymer from the product after the polymerization reaction is completed, and performing an acid removal treatment on the polymer, wherein the polymer is converted into a nitrogen-containing branched polymer after the acid removal treatment; S5. preparing a quaternization reaction solution by adding the nitrogen-containing branched polymer and a quaternization reagent into a solvent B, and then allowing the nitrogen-containing branched polymer and the quaternization reagent to undergo a quaternization reaction, and separating an anion exchange resin from the product from the quaternization reaction; and S6. preparing a homogeneous solution containing the anion exchange resin in a solute, and then coating a thin film substrate with the homogeneous solution, and drying to obtain an anion exchange membrane.

[0091] In some embodiments, in S1, the acid catalyst is added to the reaction monomer mixture in a dropwise feeding manner, and the dropwise feeding speed is 0.3 mL / min-2 mL / min.

[0092] In some embodiments, the reaction time of the oligomerization reaction is 1 hour-5 hours, and the reaction time of the polymerization reaction is 1 hour-15 hours.

[0093] In some embodiments, the reaction temperature of the quaternization reaction is 10℃-100℃.

[0094] In some embodiments, the reaction time of the quaternization reaction is 4 hours-36 hours.

[0095] In some embodiments, S6 specifically comprises the following operations: dissolving the anion exchange resin in solvent C, filtering the mixture obtained thereby through a membrane, wherein the mesh number of the membrane is 2000-6000 meshes, the filtrate filtered through the membrane is a homogeneous solution, using the homogeneous solution to coat a thin film substrate, and drying the semi-finished product obtained thereby at 60℃ for 8 hours-12 hours.

[0096] In some embodiments, solvent C is composed of at least one of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, acetonitrile.

[0097] The application provides an electrochemical device comprising the anion exchange membrane in the embodiments of the anion exchange membrane of the application. Based on the application of the anion exchange membrane provided by the application, the hydrogen in oxygen in the electrochemical device provided by the application can be long-term controlled within a safe range, thereby making it have good safety. In addition, the higher ionic conductivity of the anion exchange membrane ensures the efficient transmission of ions inside the electrochemical device, thereby making the electrochemical device have excellent electrochemical performance.

[0098] Embodiments 1-10

[0099] The method for preparing the anion exchange membrane in embodiments 1-10 is as follows:

[0100] S1. 0.27 moL of monomer I, 0.03 moL of monomer II and 0.36 moL of monomer III are added to 100 mL of dichloromethane and mixed thoroughly, thereby obtaining a reaction monomer mixture, and then an acid catalyst is added dropwise to the reaction monomer solution at a dropwise feeding speed of 1 mL / min at 0℃, and the acid catalyst specifically comprises 22.8 mL of trifluoroacetic acid and 240 mL of trifluoromethanesulfonic acid, and the solution obtained after the dropwise feeding is completed is used as a reaction solution; wherein the monomer I is an aryl monomer, the monomer II is a monomer comprising a branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle.

[0101] S2. The reaction solution is kept at the reaction temperature for oligomerization for 1-1.5 hours. In this process, the reaction monomers in the reaction solution undergo oligomerization under the action of the acid catalyst. After the oligomerization is completed, the product is an oligomer mixture.

[0102] S3. The oligomer mixture is then heated to the reaction temperature for polymerization, and kept at the reaction temperature for 2-5.5 hours. In this process, the oligomer mixture undergoes polymerization.

[0103] S4. After the reaction is completed, the polymer is discharged from the extruder into pure water, and then filtered, washed with pure water, and dried. The polymer thus obtained is dissolved in an alkaline solution for acid removal treatment. After the acid is sufficiently removed, the precipitate is washed and dried, thereby obtaining a nitrogen-containing branched polymer.

[0104] S5. The nitrogen-containing branched polymer obtained after S4 is completed is 0.1 mol, and methyl p-toluenesulfonate is 0.15 mol, which are added to 200 mL of dimethyl sulfoxide, and mixed thoroughly, thereby obtaining a quaternary ammonium reaction solution. The quaternary ammonium reaction solution is then heated to 80°C, and kept at 80°C for 15 hours. The product solution thus obtained is then precipitated by adding ethyl acetate (2 L). The precipitate is then obtained by filtration from the product solution, washed with ethyl acetate, and then ion-exchanged with 1M KBr aqueous solution (1 L), and dried, thereby obtaining an anion exchange resin.

[0105] S6. The anion exchange resin is dissolved in dimethyl sulfoxide (DMSO) to obtain a homogeneous solution with a solid content of 20 wt%. The homogeneous solution is cast onto a coating machine, and the semi-finished product thus obtained is dried at 60°C for 8 hours. The dried film is then immersed in 1M KOH at 60°C for 48 hours, thereby obtaining an anion exchange membrane.

[0106] In this example, different experimental groups are set by taking the types of monomer I, monomer II, and monomer III in the raw materials as variables. Based on the specific monomer I and monomer II selected in different experimental groups, the reaction temperature and reaction time of the oligomerization involved in S2 and S3 in the preparation of an anion exchange membrane are adaptively adjusted. The variable setting in each experimental group is shown in Table 1. Except for the variables shown in Table 1, the other experimental operations and raw materials used in all experimental groups in this example are strictly kept consistent.

[0107] Table 1. Example 1-10 and variable settings between each example

[0108] The anion exchange resin numbers prepared in Examples 1-10 are shown in detail in Table 2, which shows the weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymers corresponding to each experimental group after step S4 in the preparation of the anion exchange resin.

[0109] Table 2. Nitrogen-containing branched polymers and anion exchange resins prepared in Examples 1-10

[0110] Each anion exchange resin and the corresponding chemical structure shown in Table 2 are as follows.

[0111] Anion exchange resin A

[0112] Anion exchange resin B

[0113] Anion exchange resin C

[0114] Anion exchange resin D

[0115] Anion exchange resin E

[0116] Anion exchange resin F

[0117] Anion exchange resin G

[0118] Anion exchange resin H

[0119] Anion exchange resin I

[0120] Anion exchange resin J

[0121] Test Example 1

[0122] 1. Test object

[0123] The anion exchange resins and anion exchange membranes prepared in Examples 1-10 were used as test objects in this test example.

[0124] 2. Test items and test methods

[0125] (1) Solubility test

[0126] The anion exchange resins were each dissolved in a certain amount of dimethyl sulfoxide, and the solubility was observed for 24 hours at 80°C.

[0127] Solubility rating criteria: good solubility, marked as “++”; slightly soluble, marked as “+-”; insoluble, marked as “-”.

[0128] (2) Mechanical property test

[0129] Test method:

[0130] Under the constant temperature and humidity conditions of 23℃±2℃ and 50%±10% relative humidity, the thickness and width of the anion exchange membrane were measured. The test anion exchange membrane was placed in the test fixture, and different tensile speeds could be used when measuring the tensile strength and elongation at break, selected from the range of 50mm / min-200mm / min. For each tensile speed, a separate sample should be applied. After the sample broke, the corresponding load value was read.

[0131] a. Tensile strength: the maximum load that the anion exchange membrane could withstand under the action of pure tensile force when it broke, and the ratio of the tensile membrane width, divided into transverse and longitudinal tensile strength, to evaluate the mechanical strength of the membrane;

[0132] b. Elongation at break: the ratio of the distance between two points to the original length when the anion exchange membrane broke under the maximum load before breaking. It represents the maximum deformation that the alkaline membrane can withstand before breaking, and is used to represent the flexibility of the anion exchange membrane.

[0133] (3) Water absorption and swelling property test

[0134] Test method:

[0135] a. The anion exchange membrane was cut into 1cm*4cm size, placed in 1M KOH for three times of base exchange, and the swelling property test was carried out in 80℃ deionized water;

[0136] b. The anion exchange membrane was cut into 5cm*5cm size, placed in 1M KOH for three times of base exchange, and the water absorption property test was carried out in 80℃ deionized water.

[0137] (4) OH - ion conductivity performance (conductivity test membrane state is OH - @ 80℃@ pure water)

[0138] The anion exchange membrane was cut into 10mm*45mm as a sample. The sample was placed in 1M KOH aqueous solution, and ion exchange was carried out at 80℃ for 24 hours. After completion, it was washed to neutral with deionized water and stored in deionized water. Before testing, the thickness and width of the anion exchange membrane were measured with a thickness gauge and a ruler respectively, and the average values of three tests were taken as the width a and the thickness b respectively. At least 3 points were taken for each sample.

[0139] The ion conductivity testing device is shown in Figure 1, and a four-electrode probe method is used for testing. First, the sample is laid flat on the platinum wire electrode without wrinkles to ensure good contact between the sample and the platinum wire electrode, then the cover is placed lightly, and the screw is tightened with a wrench. After tightening, the sample should have no protrusions, and the assembly of the test module is complete.

[0140] The test fixture is connected to the temperature and humidity control system. After connection, N2 (99.999%, same below) is purged, and the flow rate on both sides is set to 500 sccm. The humidification condition is set to 100% RH, and the temperature of the pipeline is ensured to be 5°C higher than the temperature of the testing device; the actual test temperature is set according to the requirements. Then start the temperature and humidity device, and after reaching the set conditions, start the electrolysis process, keep N2 purging throughout the process, and the gas flow rate remains unchanged.

[0141] (5) Electrolysis water test

[0142] The constant current method is used to electrolyze the anion exchange membrane to be tested. The electrolysis current value can be adjusted within 2V to meet the actual test requirements. During the electrolysis process, the electrode undergoes an electrochemical reaction, and the carbonate (hydrogen) ions in the anion exchange membrane are discharged in the form of CO2 gas, until all the anions in the membrane are exchanged in situ to OH - The equilibrium of electrolysis is determined by the change of overpotential during the test process. Generally, when the electrolysis potential fluctuation value is less than 1%, the electrolysis process is determined to be complete, and the system reaches a balanced state.

[0143] a. EIS test process

[0144] After electrolysis equilibrium, EIS test is performed, the current perturbation mode is selected, the frequency range is 0.1 Hz-1.0 MHz, the perturbation amplitude is 1 mA, and the impedance spectrum is obtained. The impedance value R of the anion exchange membrane is read from the intersection of the low frequency part of the spectrum and the real axis, and the in-plane ion conductivity of the sample is calculated according to the following formula:

[0145] σ = l / (a x b x R)

[0146] In the formula:

[0147] σ - the in-plane ion conductivity of the sample, in units of millisiemens per centimeter (mS / cm);

[0148] l - the distance between the electrodes, in units of centimeters (cm);

[0149] a - the width of the membrane sample, in units of centimeters (cm);

[0150] b - the thickness of the membrane sample, in units of centimeters (cm);

[0151] R - is the measured impedance of the membrane sample in ohms (Ω).

[0152] b. Polarization performance test

[0153] The polarization curve of the alkaline membrane single cell was tested under the anode nickel ferrite-cathode platinum carbon catalytic system 60℃@1M KOH.

[0154] c. Oxygen hydrogen test

[0155] The oxygen on the anode side was tested online by GC to obtain the oxygen hydrogen data.

[0156] 3. Test results

[0157] The test results of this test example are recorded in Tables 3 and 4, Figure 2 is made based on the data in Table 3, which shows the comparison of the tensile strength and elongation at break of the test objects of this test example, Figures 3 and 4 are made based on the data in Table 4, Figure 3 shows the comparison of the ion conductivity, water absorption and swelling rate of the test objects of this test example, and Figure 4 shows the comparison of the oxygen hydrogen content and polarization performance of the alkaline membrane single cell using the test objects of this test.

[0158] From the test results, it can be seen that the anion exchange resins prepared in Example 1 all meet the following conditions: the measured tensile strength and elongation at break are both high; the measured swelling rate is low; and the measured conductivity is high. This shows that the anion exchange resins prepared in Example 1 all have good structural stability, conductivity and anti-swelling properties. Further application of the anion exchange resins prepared in Example 1 in water electrolysis tests, based on the superior properties of the anion exchange resins prepared in Example 1 such as tensile strength, elongation at break, swelling rate and conductivity, can inhibit the hydrogen gas transport across the membrane in the working process of the water electrolysis system using them, thereby controlling the hydrogen in oxygen in the water electrolysis system at a relatively low level, ensuring the working safety of the water electrolysis system, and at the same time, maintaining good ion transport effect of the water electrolysis system, ensuring the electrochemical working efficiency.

[0159] By further comparing the test results of this test example, the following examples are compared with each other in terms of the selection of raw materials, i.e., Example 2 and Example 7, Example 3 and Example 8, and Example 4 and Example 9, the difference between the mutually compared examples lies in the type of monomer I selected. By comparison, among the mutually compared examples, the use of terphenyl as monomer I for preparing anion exchange resins corresponds to better performance of the prepared anion exchange resins.

[0160] Table 3. Performance test results of the anion exchange resins and anion exchange membranes in this test example

[0161] Table 4. Test results of electrolytic water application performance of anion exchange membrane

[0162] Examples 11-16, Comparative Example 1, Comparative Example 2

[0163] With Examples 1 and 4 as references, the amount of monomers used in the preparation of anion exchange membranes was used as a variable to design experiments, thereby showing the influence of the amount of raw material monomers on the product performance of anion resin and anion exchange membranes.

[0164] (1) With Example 1 as a reference

[0165] With Example 1 as a reference, Examples 11, 12, 13, and 14 were set up. Compared with Example 1, the variables of Examples 11, 12, 13, and 14 were the amounts of p-terphenyl and 1,3,5-triphenylbenzene used in the preparation of anion exchange membranes. The amounts of p-terphenyl and 1,3,5-triphenylbenzene used in Examples 11, 12, 13, and 14 were shown in Table 5. Except for the variables shown in Table 5, the other experimental operations and raw material usage of Examples 11, 12, 13, and 14 were strictly consistent with Example 1.

[0166] Table 5. Amounts of p-terphenyl and 1,3,5-triphenylbenzene used in Examples 1, 11-14

[0167] (2) With Example 4 as a reference

[0168] With Example 4 as a reference, Examples 15, 16, Comparative Example 1, and Comparative Example 2 were set up. Compared with Example 4, the variables of Examples 15, 16, Comparative Example 1, and Comparative Example 2 were the amounts of p-terphenyl and triphenylamine used in the preparation of anion exchange membranes. The amounts of p-terphenyl and triphenylamine used in Examples 15, 16, Comparative Example 1, and Comparative Example 2 were shown in Table 6. Except for the variables shown in Table 6, the other experimental operations and raw material usage of Examples 15, 16, Comparative Example 1, and Comparative Example 2 were strictly consistent with Example 4.

[0169] Table 6. Amounts of p-terphenyl and triphenylamine used in Examples 4, 15, 16, Comparative Example 1, and Comparative Example 2

[0170] The weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymers obtained after step S4 in the process of preparing the anion exchange resin of Example 15, Example 16, Comparative Example 1, Comparative Example 2 are shown in Table 7. The weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymers obtained in Example 1, Example 4 are also loaded in Table 7 for comparison.

[0171] Table 7. The weight average molecular weight and the PDI of the nitrogen-containing branched polymers obtained in each example and comparative example

[0172] Test Example 2

[0173] 1. Test objects

[0174] The anion exchange resins and anion exchange membranes obtained in Example 11-16, Comparative Example 1, Comparative Example 2 are taken as the test objects in this test example.

[0175] 2. Test items and test methods

[0176] The test items of this test example are as follows, and the test methods of each test item of this test example are consistent with the test methods of the corresponding test items in Test Example 1.

[0177] (1) Solubility test

[0178] (2) Mechanical property test

[0179] a. Tensile strength

[0180] b. Elongation at break

[0181] (3) Water absorption and swelling property test

[0182] (4) OH - Ion conductivity performance (conductivity test film state: OH - @ 80℃ pure water)

[0183] (5) Electrolytic water test

[0184] a. EIS test process

[0185] 3. Test results

[0186] The test results of this test example are recorded in Table 8 and Table 9, Figure 5 is made based on the data in Table 8, which shows the comparison of the test results of the tensile strength and the elongation at break of the test objects in this test example, and Figures 6 and 7 are made based on the data in Table 9, Figure 6 shows the comparison of the test results of the ion conductivity, water absorption rate and swelling rate of the test objects in this test example, and Figure 7 shows the comparison of the test results of the hydrogen content in oxygen and the polarization performance of the alkaline membrane single cell using the test objects in this test.

[0187] Comparing the test results of the test objects provided by Example 1 with Example 11, Example 12, Example 13, Example 14, and comparing the test results of the test objects provided by Example 4 with Example 15, Example 16, Comparative Example 1, Comparative Example 2, the influence of the ratio of monomer I and monomer II on the product performance of the anion exchange resin in the process of preparing the anion exchange resin can be presented. As can be known from the content shown in Table 7 of the present specification, under the premise of using the same kind of reaction raw materials, the ratio of monomer I and monomer II will change the weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymer. In Example 11-16, Comparative Example 1, Comparative Example 2, the weight average molecular weight of the nitrogen-containing branched polymer corresponding to Comparative Example 1 is relatively low, less than 40000 g / mol, while the polydispersity index PDI of the nitrogen-containing branched polymer corresponding to Comparative Example 2 is relatively high, more than 2.6. Further investigating the test results shown in Table 8, the anion exchange resin prepared by Comparative Example 1 has a relatively low conductivity, while the anion exchange resin prepared by Comparative Example 2 has a relatively low tensile strength, a relatively low elongation at break, and a relatively high swelling rate. However, the anion exchange resins prepared by Example 11-16 can all have a relatively high tensile strength, a relatively large elongation at break, a relatively low swelling rate, and a relatively high conductivity. Therefore, when the nitrogen-containing branched polymer used to prepare the anion exchange resin cannot simultaneously satisfy the weight average molecular weight of not less than 40000 g / mol and the polydispersity index PDI≤2.6, the anion exchange resin cannot overcome the trade-off effect between ion conductivity, structural stability, and water absorption swelling characteristics.

[0188] According to the analysis of the test results of the present test example, the anion exchange resins prepared by Example 11, Example 12, Example 13, Example 14, Comparative Example 1, and Comparative Example 2 can all have a relatively high ion conductivity, good structural stability, and a relatively low water absorption swelling characteristic. On this basis, comparing the test results of Example 11, Example 12, Example 13, Example 14, Comparative Example 1, and Comparative Example 2 with the experimental group of Example 1 as the setting reference respectively, it can be known that in the process of preparing the anion exchange resin, controlling the molar ratio of monomer I and monomer II to be monomer I: monomer II = 85-95:5-15 can more easily prepare the nitrogen-containing branched polymer which simultaneously satisfies the weight average molecular weight of not less than 40000 g / mol and the polydispersity index PDI≤2.6.

[0189] Table 8. Performance detection results statistics of the anion exchange resins and anion exchange membranes of the present test example

[0190] Table 9. Electrolytic water application performance test results statistics of the anion exchange membranes

[0191] Example 17, Comparative Example 3-6

[0192] In this example, the anion exchange membranes were prepared by using the method of Example 1, Example 2, Example 3, Example 4, Example 5 as the control, respectively. The monomer I and monomer II used in the preparation of the anion exchange membranes were the same in the corresponding experimental groups. The control conditions of each experimental group and the specific method for preparing the anion exchange membranes are described in detail below.

[0193] (1) Example 17

[0194] With Example 1 as the reference, the method for preparing the anion exchange membrane in Example 17 is as follows:

[0195] S1. Dissolve 0.27 mol of p-terphenyl, 0.03 mol of 1,3,5-triphenylbenzene, and 0.36 mol of 3-quinuclidinone hydrochloride in 100 mL of dichloromethane, stir at 0°C, and slowly add 240 mL of triflic acid and 22.8 mL of trifluoroacetic acid dropwise. After the addition is complete, continue stirring for 72 hours to obtain a viscous solution. Wash the viscous solution with pure water, 1 mol NaOH aqueous solution, and pure water in sequence, and dry at 100°C for 30 hours to obtain a yellowish powder of nitrogen-containing branched polymer.

[0196] S2. Dissolve 0.1 mol of the nitrogen-containing branched polymer and 0.15 mol of iodomethane in dimethyl sulfoxide, and stir at 60°C for 10 hours. After the reaction is complete, wash the obtained product with pure water three times, and dry at 100°C for 30 hours to obtain a yellowish powder of anion exchange resin.

[0197] S3. Dissolve the anion exchange resin in N,N-dimethylacetamide to obtain a polymer solution. Coat the polymer solution on a glass plate, dry in an oven at 80°C for 5 hours, and then continue to dry at 120°C for 20 hours to obtain an iodine ion exchange membrane.

[0198] S4. Soak the iodine ion exchange membrane in 1M NaOH aqueous solution at room temperature for 5 hours. After taking out the membrane, wash it with pure water, and dry in a 100°C oven under nitrogen protection for 5 hours to obtain an anion exchange membrane.

[0199] (2) Comparative Example 3

[0200] With Example 2 as the reference, the method for preparing the anion exchange membrane in Comparative Example 3 is as follows:

[0201] S1. 0.27 mol of p-terphenyl, 0.03 mol of triptycene and 0.36 mol of 3-quinuclidinone were added to 100 mL of dichloromethane, stirred with a magnetic stirrer for 10 minutes in an ice water bath, air atmosphere, to obtain a light yellow mixed solution, then 240 mL of trifluoromethanesulfonic acid (TFSA) was added dropwise to the obtained mixed solution, after the dropwise addition was completed, the reaction was stirred for 36 h, the obtained viscous solution was poured into 200 mL + 200 mL of a mixed solution of water and methanol, and a yellow polymer was precipitated; the yellow polymer was stirred and crushed, then filtered and collected, washed with a 1M K2CO3 solution at room temperature for 12 hours to neutralize the residual acid in the reaction, then washed with deionized water three times, and dried in a vacuum oven at 80°C for 12 hours to obtain a nitrogen-containing branched polymer.

[0202] S2. 0.1 mol of the polymer obtained in S1 was dissolved in 30 mL of DMSO, stirred at room temperature for 30 minutes, then K2CO3 and 0.15 mol of iodomethane were added, stirred in the dark at room temperature for 12 hours, then heated to 60°C and stirred for 6 hours, 200 mL of diethyl ether was added to the obtained viscous solution, the yellow precipitate was filtered and washed with deionized water three times, and dried in a vacuum oven at 80°C for 12 hours to obtain an anion exchange resin.

[0203] S3. The anion exchange resin obtained in S2 was dissolved in 15 mL of DMSO, the polymer solution was filtered through a 0.45 μm polytetrafluoroethylene (PTFE) filter, cast on a glass plate, and then dried on a solvent evaporation heating table at 120°C for 6 hours to completely remove the residual solvent to obtain a 40 μm thick I - type polymer film.

[0204] S4. The I - type polymer film was immersed in a 1M KOH solution to obtain an OH - type film, then washed with deionized water three times, and finally an anion exchange membrane was obtained.

[0205] (3) Comparative Example 4

[0206] With Example 3 as a reference, the method for preparing an anion exchange membrane in Comparative Example 4 is as follows:

[0207] S1. 0.27 mol of p-terphenyl, 0.03 mol of triphenylmethane, and 0.36 mol of N-methyl-4-piperidone were added to 100 mL of dichloromethane, stirred with a magnetic stirrer in an ice water bath, air atmosphere for 10 min to obtain a light yellow mixed solution, then 240 mL of TFSA was added dropwise to the obtained mixed solution, and after the dropwise addition was completed, the reaction was stirred for 1 hour. The obtained viscous solution was poured into a 200 mL + 200 mL mixed solution of water and methanol to precipitate a light yellow polymer; the yellow polymer was stirred and crushed, and the crushed pieces were collected by filtration, washed with a 1M K2CO3 solution at room temperature for 12 hours to neutralize the residual acid from the reaction, then washed with deionized water three times, and dried in a vacuum oven at 80°C for 12 hours to obtain a nitrogen-containing branched polymer.

[0208] S2. 0.1 mol of the nitrogen-containing branched polymer was dissolved in DMSO, stirred at room temperature for 30 minutes, then K2CO3 and 0.15 mol of iodomethane were added, stirred in the dark at room temperature for 12 hours, then heated to 60°C and stirred for 6 hours. 200 mL of diethyl ether was added to the obtained viscous solution, and the yellow precipitate was filtered and washed with deionized water three times, and dried in a vacuum oven at 80°C for 12 hours to obtain an anion resin.

[0209] S3. The anion resin (0.4 g) was dissolved in 15 mL of DMSO, the polymer solution was filtered through a 0.45 μm polytetrafluoroethylene (PTFE) filter, cast on a glass plate, and then dried on a solvent evaporation heating table at 120°C for 6 hours to completely remove the residual solvent to obtain a 40 μm thick I - type polymer film; the I - type polymer film was immersed in a 1M KOH solution, ion exchanged at 60°C for 12 hours to obtain an OH - type film, then washed with deionized water three times, and finally an anion exchange membrane was obtained.

[0210] (4) Comparative Example 5

[0211] With Example 4 as a reference, the method for preparing an anion exchange membrane in Comparative Example 5 is as follows:

[0212] S1. 0.27 mol of p-terphenyl was added to a 250 mL three-necked flask, then 100 mL of dichloromethane solution was added, followed by the addition of 0.36 mol of N-methyl-4-piperidone and 0.03 mol of triphenylamine. After mechanical stirring for a period of time, 22.8 mL of trifluoroacetic acid, 240 mL of triflic acid were slowly added under ice bath conditions, and the reaction was maintained under ice bath conditions during the reaction, which took 4 hours. When the solution became highly viscous, the reaction solution was poured into methanol to precipitate the crude polymer, then washed with deionized water until neutral, and dried at 60°C for 24 h to obtain a nitrogen-containing branched polymer.

[0213] S2. Weigh 0.1 mol of nitrogen-containing branched polymer into 200 mL of dimethyl sulfoxide, dissolve, then add potassium carbonate and 0.15 mol of iodomethane, react at room temperature for about 36 hours, pour the obtained solution into ethyl acetate to precipitate the solid powder product, filter and dry, then wash with deionized water several times to remove unreacted salt, and dry at 60°C for 24 hours to obtain an anion exchange resin.

[0214] S3. Weigh 0.05 g of anion exchange resin into 5 mL of dimethyl sulfoxide, centrifuge the casting solution, and then cast it in a glass mold, dry at 60°C for 24 hours to obtain a polymer film, immerse the polymer film in a 1 mol / L NaOH solution at room temperature for 24 hours, then repeatedly wash and soak in deionized water for 24 hours until neutral, and an anion exchange membrane is obtained.

[0215] (5) Comparative Example 6

[0216] With Example 5 as a reference, the method for preparing an anion exchange membrane in Comparative Example 6 is as follows:

[0217] S1. Add 0.27 mol of p-terphenyl, 0.03 mol of 9,9-spirobifluorene, and 0.36 mol of N-methyl-4-piperidone into 100 mL of dichloromethane, stir with a magnetic stirrer in an ice water bath under air atmosphere for 10 minutes to obtain a light yellow mixed solution, then add 240 mL of TFSA to the obtained mixed solution, stir for 1 hour after the addition is completed, pour the obtained viscous solution into 200 mL + 200 mL of a mixed solution of water and methanol, precipitate a light yellow polymer; stir and crush the yellow polymer, collect the crushed pieces by filtration, wash with a 1M K2CO3 solution at room temperature for 12 hours to neutralize the residual acid in the reaction, then wash with deionized water three times, and dry in a vacuum oven at 80°C for 12 hours to obtain a nitrogen-containing branched polymer.

[0218] S2. Dissolve 0.1 mol of nitrogen-containing branched polymer in DMSO, stir at room temperature for 30 minutes, then add K2CO3 and 0.15 mol of iodomethane, stir in the dark at room temperature for 12 hours, then heat to 60°C and stir for 6 hours, add 200 mL of diethyl ether to the obtained viscous solution, filter the yellow precipitate, rinse with deionized water three times, and dry in a vacuum oven at 80°C for 12 hours to obtain a quaternized branched anion exchange resin.

[0219] S3. Dissolve the anion exchange resin (0.4 g) in DMSO (15 mL), filter the polymer solution through a 0.45 μm polytetrafluoroethylene (PTFE) filter, cast on a glass plate, and then dry on a solvent evaporation heating stage at 120 °C for 6 hours; after complete removal of the residual solvent, a 40 μm thick I-type polymer membrane is obtained; immerse the I - type polymer membrane in a 1 M KOH solution, ion exchange at 60 °C for 12 hours to obtain an OH - type membrane, then wash with deionized water for 3 times, and finally obtain an anion exchange membrane.

[0220] The weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymers prepared in the process of preparing the anion exchange resins of Example 17, Comparative Examples 3-6 are shown in Table 10. As can be seen from the settings of Example 17, Comparative Examples 3-6, each of which respectively takes the specific experimental group in Example 1 as a reference, in the case of using the same monomer I and monomer II as in Example 1 as a reference, a different synthesis method is used to prepare the nitrogen-containing branched polymer. By comparing the data shown in Table 10 with the data shown in Table 2, it can be seen that the difference in preparation method can cause significant changes in the weight average molecular weight and the polydispersity index PDI of the nitrogen-containing branched polymer. Among them, although Comparative Examples 3-6 can prepare nitrogen-containing branched polymers with appropriate weight average molecular weight, the polydispersity index PDI of the nitrogen-containing branched polymer is as high as 2.6 or more.

[0221] Table 10. Weight average molecular weight and PDI of the nitrogen-containing branched polymers prepared in Example 17, Comparative Examples 3-6

[0222] Test Example 3

[0223] 1. Test object

[0224] The anion exchange resins and anion exchange membranes prepared in Example 17, Comparative Examples 3-6 are taken as the test objects in this test example.

[0225] 2. Test items and test methods

[0226] The test items of this test example are as follows, and the test method of each test item of this test example is consistent with the test method of the corresponding test item in Test Example 1.

[0227] (1) Solubility test

[0228] (2) Mechanical property test

[0229] a. Tensile strength

[0230] b. Elongation at break

[0231] (3) Water absorption and swelling property test

[0232] (4) OH - Ion conductivity property (conductivity test membrane state is OH - @ 80°C pure water)

[0233] (5) Electrolytic water test

[0234] a. EIS test process

[0235] b. Polarization property test

[0236] c. Hydrogen in oxygen test

[0237] 3. Test results

[0238] The test results of the present test example are recorded in Table 11 and Table 12, based on the data in Table 11, Figure 8 is made, which shows the tensile strength and elongation at break of the test objects of the present test example. Based on the data in Table 12, Figures 9, 10 are made, Figure 9 shows the ion conductivity, water absorption and swelling rate of the test objects of the present test example, and Figure 10 shows the hydrogen content in oxygen and polarization property of the basic membrane single cell using the test objects of the present test.

[0239] As can be seen from the comparison of Example 17, Comparative Examples 3-6, in the case of the same kind of monomer raw material for preparing nitrogen-containing branched polymers, the preparation method will affect the weight average molecular weight and polydispersity PDI of the nitrogen-containing branched polymers. The test results of the present test example show that in the test objects of the present test example, the anion exchange resin provided by Example 17 can have higher ion conductivity, good structural stability and lower water absorption and swelling properties, and the comprehensive performance is obviously better than the anion exchange resins prepared by Comparative Examples 3-6 respectively. However, when the anion exchange resin of Example 17 is compared with the anion exchange resin prepared in Example 1, the comprehensive performance of the anion exchange resin prepared in Example 1 is better.

[0240] Table 11. Performance test results of the test anion exchange resins and anion exchange membranes of the present test example

[0241] Table 12. Electrolytic water application performance test results of the anion exchange membranes

[0242] Examples 18-21, Comparative Example 7, Comparative Example 8

[0243] Using Example 1 as a reference, Examples 18, 19, 20, 21, Comparative Example 7, and Comparative Example 8 were set up. The acid catalyst used in the preparation of the anion exchange membrane was used as a variable to design experiments to show the effect of the use of acid catalyst on the product performance of anion resin and anion exchange membrane.

[0244] The variables between Examples 18-21, Comparative Examples 7, and Comparative Examples 8 are: the type and amount of acid catalyst used in the preparation of anion exchange membranes. The use of acid catalysts in the preparation of anion exchange membranes in Examples 18-21, Comparative Examples 7, and Comparative Examples 8 is shown in Table 13. In Examples 1, 18, 19, Comparative Examples 7, and 8, the acid catalysts used were all compounded from trifluoroacetic acid and trifluoromethanesulfonic acid in a volume ratio of trifluoroacetic acid:trifluoromethanesulfonic acid = 22.8:240. The acid catalyst used in Example 20 was trifluoroacetic acid, and the acid catalyst used in Example 21 was trifluoromethanesulfonic acid. The equivalent amount of acid catalysts shown in Table 13 is based on the amount of monomer III fed as an equivalent reference.

[0245] Except for the variables shown in Table 13, the experimental procedures and raw material usage in Examples 18-21, Comparative Examples 7 and 8 were strictly consistent with those in Example 1.

[0246] Table 13. Acid catalyst usage in Examples 18-21, Comparative Example 7, and Comparative Example 8

[0247] Table 14 shows the weight-average molecular weight and polydispersity index (PDI) of the nitrogen-containing branched polymers obtained after step S4 in the preparation of anion exchange resins in Examples 18-21, Comparative Examples 7, and Comparative Examples 8. For ease of comparison, Table 14 also includes the weight-average molecular weight and PDI of the nitrogen-containing branched polymers obtained in Example 1. In Comparative Example 7, the polymerization reaction failed during the preparation of the nitrogen-containing branched polymer, resulting in an excessively low molecular weight. In Comparative Example 8, rapid polymerization occurred during the preparation of the nitrogen-containing branched polymer, leading to non-uniform molecular weight. From the preparation of nitrogen-containing branched polymers in Examples 1, 18, 19, 20, and 21, it can be seen that using any one of trifluoroacetic acid and trifluoromethanesulfonic acid, or a combination of both, as an acid catalyst for the preparation of nitrogen-containing branched polymers can successfully catalyze the polymerization reaction of the raw material monomers, successfully preparing nitrogen-containing branched polymers.

[0248] Table 14. Weight-average molecular weight and PDI of nitrogen-containing branched polymers obtained in Examples 18-21, Comparative Examples 7 and 8

[0249] Note: " / " means that the polymerization reaction for preparing nitrogen-containing branched polymer failed, no film material performance data or explosive polymerization resulted in uneven molecular weight, the polymer was not dissolved, and film material performance data could not be obtained.

[0250] Test Example 4

[0251] 1. Test object

[0252] The anion exchange resins and anion exchange membranes prepared in Examples 18-21, Comparative Example 7, and Comparative Example 8 were used as test objects in this test example.

[0253] 2. Test items and test methods

[0254] The test items of this test example are as follows, and the test methods for each test item of this test example are consistent with the test methods for the corresponding test items in Test Example 1.

[0255] (1) Solubility test

[0256] (2) Mechanical property test

[0257] a. Tensile strength

[0258] b. Elongation at break

[0259] (3) Water absorption and swelling property test

[0260] (4) OH - Ion conductivity performance (conductivity test film state: OH - @ 80°C pure water)

[0261] (5) Electrolytic water test

[0262] a. EIS test process

[0263] b. Polarization performance test

[0264] c. Oxygen hydrogen test

[0265] 3. Test results

[0266] The test results of this test example are recorded in Tables 15 and 16, Figure 11 is made based on the data in Table 15, and shows the comparison of the test results of the tensile strength and elongation at break of the test objects of this test example, Figures 12 and 13 are made based on the data in Table 16, Figure 12 shows the comparison of the test results of the ion conductivity, water absorption, and swelling rate of the test objects of this test example, and Figure 13 shows the comparison of the test results of the hydrogen content in oxygen and the polarization performance of the basic membrane single cell using the test objects of this test.

[0267] The anion exchange resins provided by Comparative Example 7 and Comparative Example 8 are not dissolved, so the corresponding product performance of the test objects provided by Comparative Example 7 and Comparative Example 8 cannot be measured. Except for Comparative Example 7 and Comparative Example 8, the remaining test objects of this test example all have good comprehensive performance. Among them, the equivalent of the acid catalyst used in the preparation of the nitrogen-containing branched polymer in Example 1, Example 20, and Example 21 is the same, and under this condition, the anion exchange resin and the corresponding product performance of the anion exchange membrane prepared in Example 1 show obvious comprehensive advantages, which shows that compared with using any one of trifluoroacetic acid and triflic acid as an acid catalyst for preparing a nitrogen-containing branched polymer, the combination of trifluoroacetic acid and triflic acid as an acid catalyst for preparing a nitrogen-containing branched polymer can play a synergistic role, and the comprehensive performance of the subsequently prepared anion exchange resin and anion exchange membrane is further improved.

[0268] Table 15. Performance test results of the anion exchange resins and anion exchange membranes of this test example

[0269] Note: “ / ” represents that the reaction fails to produce membrane material performance data or that the molecular weight is not uniform due to explosive polymerization, and the polymer cannot be dissolved to obtain membrane material performance data.

[0270] Table 16. Test results of the electrolytic water application performance of the anion exchange membranes

[0271] Note: “ / ” represents that the reaction fails to produce membrane material performance data or that the molecular weight is not uniform due to explosive polymerization, and the polymer cannot be dissolved to obtain membrane material performance data.

[0272] Example 22, 23

[0273] Example 22 and Example 23 are prepared by referring to the method for preparing an anion exchange membrane of Example 1, and the difference between Example 1 and Example 22 and Example 23 is that the types of monomer I, monomer II, and monomer III in the raw materials are changed in the preparation of the anion exchange membrane. Based on the selected specific monomer I and monomer II, the reaction temperature and reaction time of the oligomerization reaction involving S2 and S3 in the preparation of the anion exchange membrane and the reaction temperature and reaction time of the polymerization reaction are adaptively adjusted, and the specific conditions are shown in Table 17. Except for the above-mentioned differences, the other experimental operations and raw material usage of Example 22 and Example 23 are strictly consistent with Example 1.

[0274] Table 17. Experimental groups set by Example 22 and Example 23 and the variable settings in each group

[0275] The anion exchange resin prepared in the process of preparing the anion exchange membrane of Example 22 is designated as anion exchange resin K, and the anion exchange resin prepared in the process of preparing the anion exchange membrane of Example 23 is designated as anion exchange resin L.

[0276] Anion exchange resin K

[0277] Anion exchange resin L

Claims

1. A nitrogen-containing branched polymer, comprising a nitrogen-containing heterocycle, a branched structure and an aryl group in a molecular structure of the nitrogen-containing branched polymer, wherein a number of branched points of each of the branched structures is not less than 3, and the aryl group is connected to a branched site of the branched structure through the nitrogen-containing heterocycle; wherein A represents a molar ratio of the aryl group in the nitrogen-containing branched polymer, and B represents a molar ratio of the branched structure in the nitrogen-containing branched polymer, and A: B = 80-99: 1-20; wherein a polydispersity index (PDI) of the nitrogen-containing branched polymer is less than or equal to 2.6, and a weight average molecular weight of the nitrogen-containing branched polymer is 40,000-500,000 g / mol. The aryl group comprises at least one of biphenyl, terphenyl, and quaterphenyl.

2. The nitrogen-containing branched polymer of claim 1, wherein: The branched structure comprises a benzene ring structure provided with a branched site.

3. The nitrogen-containing branched polymer of any one of claims 1-2, wherein: The branched structure comprises at least one of 1, 3, 5-triphenylbenzene structural unit, triphenylmethane structural unit, 9, 10-benzo phenanthrene structural unit, tetraphenylmethane structural unit, triptych structural unit, 9, 9-diphenylfluorene structural unit, 9, 9'-spirobifluorene structural unit, 9, 9'-bifluorene structural unit, 9, 9'-biscarbazole structural unit, 4, 4'-bis (9-carbazole) biphenyl structural unit, 2, 2"-linked-9, 9'-spirobis[9H-fluorene] structural unit, and triphenylamine structural unit.

4. The nitrogen-containing branched polymer of claim 3, wherein: The nitrogen-containing heterocycle comprises at least one of piperidine ring and quinuclidine ring.

5. The nitrogen-containing branched polymer of any one of claims 1-4, wherein: 6.The nitrogen-containing branched polymer according to any one of claims 1-5, wherein: the molecular structure of the nitrogen-containing branched polymer comprises a segment I and a segment II; wherein A represents the nitrogen-containing heterocycle, Ar 1 represents the aryl group, and X represents a polymerization degree of the segment I; the segment II is composed of the nitrogen-containing heterocycle and the branched structure, and in the segment II, the nitrogen-containing heterocycle is directly connected to a branched site of the branched structure. 7.The nitrogen-containing branched polymer according to claim 6, wherein: the nitrogen-containing branched polymer comprises a basic structural unit connected by the segment I and the segment II; in the basic structural unit, the segment I and the segment II are connected in such a way that the aryl group in the segment I is connected to the nitrogen-containing heterocycle in the segment II; in the basic structural unit, a number of the segment I directly connected to each of the segment II is greater than or equal to 3; and a weight average molecular weight of the nitrogen-containing branched polymer is 40,000-250,000 g / mol. The aryl group is terphenyl. The structural general formula of the segment I is The nitrogen-containing polymer comprises at least one of nitrogen-containing branched polymer A, nitrogen-containing branched polymer B, nitrogen-containing branched polymer C, nitrogen-containing branched polymer D, and nitrogen-containing branched polymer E. 12.A method for preparing the nitrogen-containing branched polymer according to any one of claims 1-11, comprising the following operations: the monomer I is an aryl monomer, the monomer II is a monomer comprising the branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle; an acid catalyst is added to a reaction monomer mixture at a temperature of-5-0 ℃ to obtain a reaction solution. ​ ​ ​ 8. The nitrogen-containing branched polymer of claim 7, wherein: ​ 9. The nitrogen-containing branched polymer of any one of claims 1-8, wherein: ​ 10. The nitrogen-containing branched polymer of any one of claims 1-9, wherein: ​ 11. The nitrogen-containing branched polymer of claim 10, wherein: ​ The nitrogen-containing branched polymer A is The nitrogen-containing branched polymer B is The nitrogen-containing branched polymer C is The nitrogen-containing branched polymer D The nitrogen-containing branched polymer E ​ S1. Preparing a reaction monomer mixture solution containing monomer I, monomer II, and monomer III, wherein, ​ S2. Subjecting the reaction liquid to an oligomerization reaction, the oligomerization reaction being carried out at a temperature of 0-10°C, and obtaining an oligomer mixture after the oligomerization reaction is completed; S3. Subjecting the oligomer mixture to a polymerization reaction, the polymerization reaction being carried out at a temperature of 0-24°C; S4. Separating the polymer from the product after the polymerization reaction is completed, and subjecting the polymer to an acid-removing treatment, the polymer being converted into the nitrogen-containing branched polymer after the acid-removing treatment.

13. An anion exchange resin, the anion exchange resin comprising a quaternized product of the nitrogen-containing branched polymer according to any one of claims 1-11.

14. A method for preparing the anion exchange resin according to claim 13, comprising the following operations: S1. A reaction monomer mixture solution containing monomer I, monomer II, and monomer III is prepared, wherein, The monomer I is an aryl monomer, the monomer II is a monomer comprising the branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle; an acid catalyst is added to the reaction monomer mixture at a temperature of -5-0°C to obtain a reaction liquid; S2. Subjecting the reaction liquid to an oligomerization reaction, the oligomerization reaction being carried out at a temperature of 0-10°C, and obtaining an oligomer mixture after the oligomerization reaction is completed; S3. Subjecting the oligomer mixture to a polymerization reaction, the polymerization reaction being carried out at a temperature of 0-24°C; S4. Separating the polymer from the product after the polymerization reaction is completed, and subjecting the polymer to an acid-removing treatment, the polymer being converted into the nitrogen-containing branched polymer after the acid-removing treatment. S5. Preparing a quaternization reaction liquid by adding the nitrogen-containing branched polymer and a quaternization reagent into a solvent B, and then subjecting the nitrogen-containing branched polymer to a quaternization reaction with the quaternization reagent, and separating the anion exchange resin from the product obtained from the quaternization reaction.

15. The method of claim 14, wherein the anion exchange resin is prepared by the process comprising: The monomer I includes at least one of the following aryl monomers:

16. The method of preparing an anion exchange resin according to any one of claims 14-15, wherein, The monomer II includes at least one of the following materials:

17. The method of preparing an anion exchange resin according to any one of claims 14 to 16, wherein: The monomer III comprises at least one of a piperidone monomer and a quinuclidone monomer.

18. The method for preparing the anion exchange resin according to claim 17, wherein: The piperidone monomers include at least one of the following materials, The quinuclidone monomer includes at least one of the following materials, 19. The method of preparing an anion exchange resin according to any one of claims 14 to 18, wherein: The acid catalyst comprises at least one of methylsulfonic acid, pentafluoropropionic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, heptafluorobutyric acid, and the amount of the acid catalyst added is 4-14 eq with reference to the amount of the monomer III as an equivalent.

20. The method of preparing an anion exchange resin according to any one of claims 14 to 19, wherein: The quaternization reagent comprises at least one of methyl trifluoroacetate, methyl p-toluenesulfonate, methyl iodide, propyl bromide, ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, ethyl bromide, butyl bromide, pentyl bromide, hexyl bromide, cyclohexyl bromide, cyclopentyl bromide, cyclohexyl bromide, methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, butyl methanesulfonate, propyl ethanesulfonate, ethyl ethanesulfonate, but-3-yn-1-yl methanesulfonate, allyl allyl sulfonate, methyl benzenesulfonate, methyl nitrobenzenesulfonate, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, ethyl toluenesulfonate, cyclobutyl toluene-4-sulfonate, butyl toluenesulfonate, neopentyl benzenesulfonate, tetrahydro-2H-pyran-4-yl methanesulfonate, or cyclohexyl p-toluenesulfonate.

21. The method of preparing an anion exchange resin according to any one of claims 14 to 20, wherein, The preparation of the reaction monomer mixture includes the following steps: mixing the monomer I, the monomer II and the monomer III in solvent A, wherein the solvent A is composed of at least one of dichloromethane, trichloromethane, chloroform or tetrahydrofuran.

22. The method of preparing an anion exchange resin according to any one of claims 14 to 21, wherein: The reaction temperature of the quaternary ammonium reaction is 10-100℃.

23. The method of making an anion exchange resin according to any one of claims 14-22, wherein: The solvent B is composed of at least one of dimethyl sulfoxide, tetrahydrofuran, N-methyl-2-pyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide, acetonitrile.

24. The preparation method of the anion exchange resin according to any one of claims 14-23, wherein: In the S5, the separation of the anion exchange resin from the product obtained from the quaternary ammonium reaction includes the following steps: adding a precipitant to the product obtained from the quaternary ammonium reaction, and washing and drying the precipitate separated from the product to obtain the anion exchange resin. The precipitant includes at least one of ethanol, ethyl acetate, ethylene glycol, diethyl ether, tetrahydrofuran, acetone or water.

25. An anion exchange membrane, comprising the anion exchange resin according to claim 13.

26. The preparation method of the anion exchange membrane according to claim 25, comprising the following steps: S1. A reaction monomer mixture solution containing monomer I, monomer II, and monomer III is prepared, wherein, The monomer I is an aryl monomer, the monomer II is a monomer comprising the branched structure, and the monomer III is a monomer comprising a nitrogen-containing heterocycle; an acid catalyst is added to the reaction monomer mixture at a temperature of -5-0℃ to obtain a reaction solution; S2. The reaction solution is subjected to an oligomerization reaction, wherein the reaction temperature of the oligomerization reaction is 0-10℃, and an oligomer mixture is obtained after the oligomerization reaction; S3. The oligomer mixture is subjected to a polymerization reaction, wherein the reaction temperature of the polymerization reaction is 0-24℃; S4. A polymer is separated from the product after the polymerization reaction, and the polymer is subjected to an acid removal treatment, and the polymer is converted into the nitrogen-containing branched polymer after the acid removal treatment; S5. The nitrogen-containing branched polymer and a quaternary ammonium reagent are added to a solvent B to prepare a quaternary ammonium reaction solution, and then the nitrogen-containing branched polymer and the quaternary ammonium reagent are subjected to a quaternary ammonium reaction, and the anion exchange resin is separated from the product obtained from the quaternary ammonium reaction; S6. A homogeneous solution containing the anion exchange resin is prepared, and then the homogeneous solution is used to coat a thin film substrate, and the thin film substrate is dried to obtain the anion exchange membrane.

27. An electrochemical device, comprising the anion exchange membrane according to claim 25.

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