An anion exchange membrane, its preparation method and application in flow battery and hydrogen production electrolyzer

Abstract

This invention belongs to the field of ion exchange membranes, and discloses an anion exchange membrane, its preparation method, and its application in flow batteries and hydrogen electrolyzers. The preparation method involves first copolymerizing tetraphenylethylene-vinyl monomers with styrene monomers via solution polymerization to obtain copolymer A; then, copolymer A undergoes a chloromethylation reaction to obtain copolymer B; finally, copolymer B reacts with trimethylamine to obtain polymer C. This polymer C can be used to fabricate anion exchange membrane using common polar, high-boiling-point solvents such as N,N-dimethylformamide via solution casting. This anion exchange membrane can be applied to flow batteries, improving coulombic efficiency and energy efficiency in vanadium redox flow battery systems and ensuring cycle stability; it is particularly suitable for use in AEM hydrogen electrolyzers, exhibiting excellent durability, high ionic conductivity, and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of ion exchange membranes, and in particular to an anion exchange membrane, its preparation method, and its application in flow batteries and hydrogen electrolyzers. Background Technology

[0002] The large-scale development of renewable energy and the efficient production of green hydrogen have become the core directions of energy transformation. Flow batteries are a key technology for large-scale energy storage, and anion exchange membrane electrolysis (AEMWE) is a highly promising "green hydrogen" production technology. Both of them place stringent requirements on the core component, the anion exchange membrane (AEM). The performance of the anion exchange membrane directly determines the energy efficiency, stability, and industrialization prospects of the two technologies.

[0003] Flow batteries, with their advantages of independently adjustable energy storage and power output, long cycle life, safety, and environmental friendliness, have become an important energy storage solution for addressing the intermittency and uncertainty of new energy power generation. Currently, mainstream flow battery technologies such as vanadium redox flow batteries and iron-chromium flow batteries primarily use cation exchange membranes (CEMs), while anion exchange membranes are used relatively less. This is mainly because anion exchange membranes have poor ion conductivity and weak durability, which limits their application in flow batteries. However, anion exchange membranes have cation groups such as quaternary ammonium groups on their surface, which can effectively repel vanadium and iron ions, reducing the risk of transmembrane permeation. This results in higher ion selectivity of the membrane material, significantly improving the battery's coulombic efficiency and drastically reducing the capacity decay rate. Therefore, developing a high-performance anion exchange membrane is a key research direction for flow batteries.

[0004] AEM (Alkaline Electrolysis) water electrolysis for hydrogen production combines the low cost of alkaline water electrolysis with the high dynamic response of proton exchange membrane (PEM) water electrolysis. It can utilize non-precious metal catalysts and is expected to become a mainstream technology for renewable energy hydrogen production. The anion exchange membrane, as the core component of the electrolyzer, is responsible for converting the OH- generated at the cathode into hydrogen. - The anion exchange membrane conducts the hydrogen to the anode while preventing cross-permeation between hydrogen and oxygen, ensuring the efficiency and safety of the electrolysis process. Currently, the industrialization bottleneck of AEM water electrolysis for hydrogen production mainly lies in the performance defects of the anion exchange membrane. Existing membrane materials are prone to polymer backbone degradation and ion exchange site loss under high alkalinity and certain temperature working environments, resulting in decreased ion conductivity and reduced mechanical strength, significantly shortening the service life of the electrolyzer. At the same time, the high preparation cost also limits its large-scale application.

[0005] In summary, both the large-scale energy storage applications of flow batteries and the green and efficient development of AEM (Alternating Electrolysis) water electrolysis for hydrogen production urgently require an anion exchange membrane that combines high ionic conductivity, excellent selectivity and barrier properties, good chemical stability and mechanical properties, and controllable manufacturing costs. Addressing the performance shortcomings of existing anion exchange membranes in these two application scenarios, developing a highly adaptable anion exchange membrane with excellent overall performance is of great significance for promoting the industrialization of flow battery energy storage technology and AEM water electrolysis for hydrogen production, and for contributing to the green energy transition. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the technical solution of the present invention is as follows: A method for preparing a polymer includes the following steps: (1) A copolymer A of the two monomers, tetraphenylethylene-vinyl monomer and styrene monomer, is obtained by solution polymerization. The tetraphenylethylene-vinyl monomer and styrene monomer are shown in Formula II. Formula II (2) Dissolve copolymer A obtained in step (1) in anhydrous dichloromethane (DCM) to obtain a solution with a concentration of 10-20 wt%. Add a slight excess of paraformaldehyde and 0.8-1.0 equivalent (preferably 1.0 equivalent) of catalyst. Then, gradually add a solution of anhydrous dichloromethane (DCM) with a concentration of 10-20 wt% in slight excess of trimethylchlorosilane (TMSCl) to the above reaction system, maintaining the reaction temperature at 35-40°C. After the dropwise addition reaction is completed, at 3 Continue stirring the reaction at 5-40℃ for 16-36 hours to allow trimethylchlorosilane to react completely. After the reaction is complete, add deionized water to the reaction system, shake thoroughly, and separate the layers. Remove the lower organic layer (dichloromethane layer), remove the unreacted catalyst, TMSCl, and paraformaldehyde, wash the organic layer with saturated brine, separate the layers, dry the organic layer with anhydrous sodium sulfate, and then evaporate the solvent using a rotary evaporator to obtain the chloromethylated tetraphenylethylene-vinyl monomer and styrene monomer copolymer B. (3) Dissolve the copolymer B obtained in step (2) again in anhydrous dichloromethane, add an aqueous solution of trimethylamine containing excess trimethylamine, and stir at room temperature for more than 24 hours to ensure complete reaction. After the reaction is complete, add excess dilute hydrochloric acid (concentration of 0.5-1.0 mol / L) to the reaction system, shake thoroughly and separate the layers, remove the lower organic layer (dichloromethane layer), remove the unreacted trimethylamine, wash the organic layer with saturated brine and separate the layers, dry the organic layer with anhydrous sodium sulfate, and then evaporate the solvent by rotary evaporator to obtain polymer C.

[0007] Furthermore, in step (1), the tetraphenylethylene-vinyl monomer and styrene monomer react via solution polymerization. Solution polymerization is a common method for monomer polymerization to synthesize polymers, and is not specifically limited here. The endpoint of the solution polymerization reaction can be determined by the residual amount of double bond hydrogen <1%. If the residual amount of double bond hydrogen is <1%, it can be considered that all monomers have participated in the polymerization reaction, that is, the monomer conversion rate is ~100%, and the molar ratio of the two monomers corresponding to the structural units in the resulting copolymer A is the molar ratio of the two monomers at the initial feeding. For the calculation method of the residual amount of double bond hydrogen, please refer to Chinese Patent ZL201911226764.1 or other literature, which will not be elaborated here.

[0008] Furthermore, in step (1), the molar ratio of tetraphenylethylene-vinyl monomer to styrene monomer is (1-4):1.

[0009] Furthermore, the catalyst in step (2) is either SnCl4 or ZnCl2.

[0010] Furthermore, the "excess" mentioned in steps (2) and (3) (including slight excess and excess) refers to the total molar number of tetraphenylethylene-vinyl monomer units and styrene units in copolymer A. Slight excess generally refers to 1.1-1.2 times the total molar number, while excess refers to 2-3 times the total molar number, without specific limitations. The purpose of adding excess is to ensure sufficient reaction, which will not be elaborated further here.

[0011] A polymer is prepared according to the above preparation method. The polymer C has the molecular structure shown in Formula I, where * represents adjacent groups and the contents of parentheses represent the corresponding structural units. Formula I An anion exchange membrane comprising the aforementioned polymer C.

[0012] An anion exchange membrane, the preparation method of which further includes the following steps: (4) Dissolve the polymer C in a polar high-boiling-point solvent to make a solution, and then prepare an anion exchange membrane by solution casting method.

[0013] Furthermore, the polar high-boiling-point solvent mentioned in step (4) is a common film-forming solvent such as N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide, which is not limited here.

[0014] An anion exchange membrane is proposed for use in flow batteries. It can be applied to vanadium redox flow battery systems and, theoretically, to other flow battery systems. In vanadium redox flow battery systems, it can improve the coulombic efficiency and energy efficiency of the battery, meeting the current technical requirements of vanadium redox flow batteries for anion exchange membranes.

[0015] The above-mentioned anion exchange membrane (AEM) is used in hydrogen electrolyzers. It exhibits excellent durability in AEM hydrogen electrolyzers, as well as high ionic conductivity and mechanical properties, meeting the current technical requirements for anion exchange membranes in AEM hydrogen electrolyzers.

[0016] The main inventive points of this invention are: (1) By copolymerizing tetraphenylethylene-vinyl monomer with greater steric hindrance and styrene monomer with less steric hindrance, it can be ensured that all monomers will not be difficult to polymerize due to the large steric hindrance effect of tetraphenylethylene group in tetraphenylethylene-vinyl monomer. It can also obtain a spatial structure of molecular chains with serrated or serrated molecular chains. These molecular chains will intertwine and connect with each other during the process of solution casting and film formation, which will increase the mechanical strength of the film itself.

[0017] (2) The tetraphenylethylene group in the tetraphenylethylene-vinyl monomer with greater steric hindrance and the styrene group with less steric hindrance both contain benzene ring structure, which can enhance the structural rigidity of the molecular chain, reduce the risk of main chain breakage, and improve the durability and corrosion resistance of membrane material.

[0018] (3) By controlling the experimental conditions, each structural unit of the membrane molecule has a quaternary ammonium group, which fully ensures the ionic conductivity of the ion exchange membrane, helps to reduce the ohmic polarization inside the flow battery and hydrogen electrolyzer, and improves the charging and discharging efficiency and electrolysis efficiency.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention provides an anion exchange membrane with a novel structure. The polymer molecules that make up the ion exchange membrane have a spatial structure of serrated or serrated molecular chains, which allows the membrane material molecules to entangle with each other, thus giving the ion exchange membrane good mechanical properties.

[0020] (2) The anion exchange membrane prepared by the present invention has excellent ion conduction ability. In flow batteries, it helps to suppress the migration of active substances (such as vanadium ions) across the membrane and improve the coulombic efficiency and energy efficiency of the battery. In the field of water electrolysis for hydrogen production, it can reduce the small cell voltage of the electrolyzer and improve the Faraday efficiency.

[0021] (3) The anion exchange membrane prepared by the present invention has excellent durability or corrosion resistance and can replace the existing ion exchange membrane in the fields of flow battery energy storage and water electrolysis hydrogen production. Attached Figure Description

[0022] Figure 1 The curves show the changes in tensile strength of the membrane material after immersion in vanadium electrolyte for different times. Figure 2The curves show the changes in tensile strength of the membrane material after immersion in KOH solution for different times. Detailed Implementation

[0023] To better understand the present invention, the following embodiments further illustrate its content, but the content of the present invention is not limited to the following embodiments. The following embodiments describe in more detail an anion exchange membrane of the present invention, its preparation method, and its application in flow batteries and hydrogen electrolyzers. These embodiments are given by way of illustration, but they do not limit the scope of the present invention. Unless otherwise specified, the experimental methods used in the present invention are conventional methods, and the experimental equipment, materials, reagents, etc. used can be purchased from chemical companies.

[0024] The structural formula of the tetraphenylethylene-vinyl monomer used in the embodiments of this invention is shown in Formula III, and its synthesis method can be found in the paper. Chem.Commun. For convenience, this monomer name is simplified to monomer X. Formula III It is worth noting that the tetraphenylethylene-vinyl monomer structure is only illustrative in the embodiments and does not limit the specific structure of the tetraphenylethylene-vinyl monomer in the technical solution of the present invention. Furthermore, those skilled in the art will know that as long as the tetraphenylethylene group and the polymerizable double bond (Note: the double bond inside the tetraphenylethylene group has a large steric hindrance, and its polymerization is very difficult under the experimental conditions described in the present invention, so it is considered to be a non-polymerizable double bond, while the double bond of the vinyl group is a polymerizable double bond) coexist, its linking group will not affect the performance of the anion exchange membrane described in the present invention.

[0025] The thickness of the ion exchange membrane was measured using a digital micrometer screw gauge, with 15 values ​​measured at different locations for each sample and the average value calculated. The tensile strength of the ion exchange membrane was tested in accordance with the standard GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets". The membrane was cut into strips with a width of 10 mm and an initial clamp spacing of 50 mm, and the test was conducted at a tensile rate of 200 mm / min. The vanadium permeability coefficient test method for ion-exchange membrane samples shall be performed in accordance with the vanadium ion diffusion section of Chapter 5.9 of NB / T 42080-2023 "General Technical Conditions and Test Methods for Ion Conductive Membranes for Vanadium Redox Flow Batteries".

[0026] OH in ion-exchange membrane samples -Ionic conductivity was measured using the AC impedance method. First, the anion exchange membrane was immersed in 1 mol / L NaOH for 48 hours for ion exchange. Then, it was washed multiple times with deionized water to remove excess alkali, yielding OH⁻. - A thin film sample of the type. Then OH - An ion-exchange membrane was placed in a self-made test fixture, and a plastic-sealed frame was used to define the effective test area (S) of the membrane material. Using an electrochemical workstation and a two-electrode method, the real and imaginary resistances of the membrane sample were measured within a frequency range of 1 Hz to 100 kHz. Impedance fitting lines were selected near the high frequency (100 kHz) for both the real and imaginary parts, and the slope of the fitted lines was calculated to obtain the resistance (R) of the membrane sample. The ionic conductivity (σ) of the ion-exchange membrane material can be calculated using the formula σ = d / (RS).

[0027] This invention uses a typical flow battery—the all-vanadium redox flow battery—as an example to evaluate the performance of anion exchange membrane flow batteries. The performance test conditions for the all-vanadium redox flow battery with anion exchange membrane are: a current density of 160 mA / cm². 2 Charge-discharge experiments were conducted under the following conditions: charging to 1.55V and discharging to 1.00V. Graphite carbon felt produced by Liaoyang Jingu Carbon Materials Co., Ltd. was used as the reaction electrode, with an effective working area of ​​48 cm². 2 The positive and negative electrode electrolytes are V0 and V0, respectively. 2+ / VO2 + and V 2+ / V 3+ The battery operates at a temperature of 37°C and contains a sulfuric acid solution.

[0028] The AEM electrolysis water production hydrogen production test conditions of this invention are as follows: the ion exchange membrane is assembled in a single-chamber electrolyzer (the anode and cathode materials are nickel-iron oxide, the electrolyte is 1 mol / L potassium hydroxide, and the test temperature is 70℃), with an effective size of 5 cm. 2 (2.0cm × 2.5cm), test 1A / cm 2 Cell voltage and Faraday efficiency at current density.

[0029] The durability test method for the ion-exchange membrane in the electrolyte of a vanadium redox flow battery is as follows: the electrolyte contains 1.7 mol / L pentavalent vanadium ions (VO2). + The tensile properties of the sample were tested at different time points after immersion in sulfuric acid electrolyte at 50°C.

[0030] The durability test method for ion exchange membranes under alkaline conditions is to test the changes in tensile properties by immersing them in a 10 mol / L KOH solution at 80℃ for different time points.

[0031] In each of the following examples, anion exchange membranes of two thicknesses were prepared, approximately 50 μm and 100 μm, respectively. These two thicknesses are the conventional membrane thicknesses used in vanadium redox flow batteries and AEM water electrolysis hydrogen production electrolyzers, respectively. This is hereby noted.

[0032] Example 1 (1) Dissolve 43.9g (0.1mol) monomer X and 10.4g (0.1mol) styrene monomer (monomer ratio of 1:1) in 200mL N,N'-dimethylformamide (DMF), add 10.9g initiator azobisisobutyronitrile, and heat at 70℃ to carry out copolymerization until the reaction is completed. Remove the DMF solvent from the reaction system by vacuum distillation to obtain copolymer A1 of monomer X and styrene monomer. The monomer conversion rate is ≈100%, and the molar ratio of the two monomer structural units in copolymer A1 is 1:1.

[0033] (2) 40g of copolymer A1 was dissolved in anhydrous dichloromethane (DCM) to prepare a 10wt% solution. 5.02g of paraformaldehyde (1.1 equivalents) and 39.6g of catalyst SnCl4 were added. Then, 18.15g (0.167mol, 1.1 times excess) of anhydrous dichloromethane solution of trimethylchlorosilane (TMSCl) (10wt% concentration) was slowly added dropwise to the reaction system. The reaction temperature was controlled at 40℃. After the addition was completed, the reaction was stirred at 40℃ for 16h. After the reaction was completed, deionized water was added to the system, the mixture was shaken and separated, the organic layer was removed, and the unreacted catalyst, TMSCl and paraformaldehyde were removed. The organic layer was then washed with saturated brine and separated. The organic layer was dried with anhydrous sodium sulfate and the solvent was evaporated by a rotary evaporator to obtain chloromethylated copolymer B1.

[0034] (3) Copolymer B1 was dissolved again in anhydrous dichloromethane, and 2 equivalents (relative to the total molar number of the two monomers in copolymer A) of trimethylamine aqueous solution were added. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 2 equivalents of dilute hydrochloric acid were added, the mixture was shaken to separate the layers, the lower organic layer was removed, the unreacted trimethylamine was removed, the organic layer was washed with saturated brine and separated, the organic layer was dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation to obtain polymer C1.

[0035] (4) The polymer C1 was dissolved in N,N-dimethylformamide to prepare a 17wt% solution. The solution was cast into a film by solution casting and then air-dried to obtain anion exchange membranes with thicknesses of 49μm and 102μm as described in this invention.

[0036] Example 2 (1) Dissolve 87.8g (0.2mol) monomer X and 10.4g (0.1mol) styrene monomer (monomer ratio of 2:1) in 300mL N,N'-dimethylformamide (DMF), add 16.4g initiator azobisisobutyronitrile, and heat at 70℃ to carry out copolymerization until the reaction is completed. Remove the DMF solvent from the reaction system by vacuum distillation to obtain copolymer A2 of monomer X and styrene monomer with monomer conversion rate ≈100%. The molar ratio of the two monomer structural units in copolymer A1 is 2:1.

[0037] (2) Dissolve 60g of copolymer A2 in anhydrous dichloromethane (DCM) to prepare a 15wt% solution. Add 6.04g of paraformaldehyde (1.1 equivalents) and 38.1g of catalyst SnCl4. Then slowly add 23.9g (0.22mol, 1.2 times excess) of anhydrous dichloromethane solution of trimethylchlorosilane (TMSCl) (15wt% concentration) to the reaction system. Control the reaction temperature at 37℃. After the addition is complete, continue stirring at 37℃ for 29h. After the reaction is complete, add deionized water to the system, shake to separate the liquids, remove the organic layer, remove the unreacted catalyst, TMSCl and paraformaldehyde, wash the organic layer with saturated brine and separate the liquids. After drying the organic layer with anhydrous sodium sulfate, evaporate the solvent by rotary evaporator to obtain chloromethylated copolymer B2.

[0038] (3) Copolymer B2 was dissolved again in anhydrous dichloromethane, and 2.3 equivalents (relative to the total molar number of the two monomers in copolymer A) of trimethylamine aqueous solution were added. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 2 equivalents of dilute hydrochloric acid were added, the mixture was shaken to separate the layers, the lower organic layer was removed, the unreacted trimethylamine was removed, the organic layer was washed with saturated brine and separated, the organic layer was dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation to obtain polymer C2.

[0039] (4) Dissolve polymer C2 in N,N-dimethylformamide to prepare a solution with a concentration of 15wt%, cast the film by solution casting method, and air dry to obtain anion exchange membranes with thicknesses of 52μm and 101μm as described in this invention.

[0040] Example 3 (1) Dissolve 87.8g (0.2mol) monomer X and 5.2g (0.05mol) styrene monomer (monomer ratio of 4:1) in 300mL N,N'-dimethylformamide (DMF), add 15.5g initiator azobisisobutyronitrile, and heat at 70℃ to carry out copolymerization until the reaction is completed. Remove the DMF solvent from the reaction system by vacuum distillation to obtain copolymer A3 of monomer X and styrene monomer. The monomer conversion rate is ≈100%, and the molar ratio of the two monomer structural units in copolymer A3 is 4:1.

[0041] (2) 58g of copolymer A3 was dissolved in anhydrous dichloromethane (DCM) to prepare a 20wt% solution. 5.58g of paraformaldehyde (1.2 equivalents) and 40.4g of catalyst SnCl4 were added. Then, 19.56g (0.18mol, 1.15 times excess) of anhydrous dichloromethane solution of trimethylchlorosilane (TMSCl) (20wt% concentration) was slowly added dropwise to the reaction system. The reaction temperature was controlled at 37℃. After the addition was completed, the reaction was stirred at 35℃ for 36h. After the reaction was completed, deionized water was added to the system, the mixture was shaken and separated, the organic layer was removed, and the unreacted catalyst, TMSCl and paraformaldehyde were removed. The organic layer was then washed with saturated brine and separated. The organic layer was dried with anhydrous sodium sulfate and the solvent was evaporated by a rotary evaporator to obtain chloromethylated copolymer B3.

[0042] (3) Copolymer B3 was dissolved again in anhydrous dichloromethane, and 2.9 equivalents (relative to the total molar number of the two monomers in copolymer A) of trimethylamine aqueous solution were added. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 2.4 equivalents of dilute hydrochloric acid were added, the mixture was shaken and separated, the lower organic layer was removed, unreacted trimethylamine was removed, the organic layer was washed with saturated brine and separated, the organic layer was dried with anhydrous sodium sulfate and the solvent was removed by rotary evaporation to obtain polymer C3.

[0043] (4) Dissolve polymer C3 in dimethyl sulfoxide to prepare a solution with a concentration of 20 wt%, cast the film by solution casting method, and air dry to obtain anion exchange membranes with thicknesses of 50 μm and 98 μm as described in this invention.

[0044] Comparative Example 1 43.9 g (0.1 mol) of monomer X and 20.8 g (0.2 mol) of styrene monomer (monomer ratio of 1:2) were subjected to solution polymerization reaction. The reaction conditions and feeding ratio were kept the same as in Example 2. Anion exchange membranes with thicknesses of 48 μm and 101 μm were obtained.

[0045] Comparative Example 2 131.7 g (0.3 mol) of monomer X and 5.2 g (0.05 mol) of styrene monomer (monomer ratio of 6:1) were subjected to solution polymerization reaction. The reaction conditions and feeding ratio were the same as in Example 3, and anion exchange membranes with thicknesses of 49 μm and 100 μm were obtained.

[0046] Table 1. Test data of the anion exchange membranes prepared in Examples 1-3 and the comparative examples in vanadium redox flow batteries. From Table 1 and Figure 1 It can be seen that, compared with Comparative Examples 1 and 2, as well as the commercially available Fumasep FAA3-50 membrane and Nafion 212 membrane, the anion exchange membrane prepared in this invention: 1) has a lower vanadium ion permeation coefficient and a higher coulombic efficiency, demonstrating the excellent vanadium blocking performance of the anion exchange membrane prepared in this invention; 2) has higher tensile strength, demonstrating the excellent mechanical properties of the anion exchange membrane prepared in this invention, while the different monomer feed ratios in Comparative Examples 1 and 2 make it difficult for the membrane molecular chains to form a "zigzag" structure, resulting in a significant decrease in their mechanical properties; 3) has higher energy efficiency, indicating that the anion exchange membrane prepared in this invention has good ion conduction performance, which can reduce the battery internal resistance to a certain extent and reduce energy loss; 4) has higher energy efficiency in the presence of pentavalent vanadium ions (VO2+). + Immersed in a sulfuric acid electrolyte at 50°C, the anion exchange membrane prepared according to this invention exhibits durability similar to that of the Nafion 212 perfluorosulfonic acid ion exchange membrane, and its 28-day tensile strength decay rate is significantly lower than that of the commercially available Fumasep FAA3-50 anion exchange membrane. This fully demonstrates that the anion exchange membrane prepared according to this invention possesses excellent corrosion resistance and durability. The above data confirm that the anion exchange membrane described in this invention has excellent comprehensive performance and can meet the technical requirements of vanadium redox flow batteries.

[0047] Table 2. Test data of the anion exchange membranes prepared in Examples 1-3 and the comparative examples in hydrogen electrolyzers. From Table 2 and Figure 2 It can be seen that the anion exchange membranes prepared in Examples 1-3 of this invention are comparable to those in Comparative Examples 1 and 2 and the commercially available FORBLUE. TMCompared to the SELEMION AMWE-1091 membrane: 1) it exhibits higher ionic conductivity and lower chamber voltage, indicating a lower ohmic polarization resistance in the hydrogen electrolyzer; 2) it demonstrates higher tensile strength, showcasing the excellent mechanical properties of the anion exchange membrane prepared in this invention. In contrast, the different monomer feed ratios in Comparative Examples 1 and 2 resulted in membrane molecular chains that were difficult to form a "zigzag" structure, leading to a significant decrease in their mechanical properties; 3) it possesses higher Faraday efficiency, indicating that the anion exchange membrane prepared in this invention exhibits good OH- ion exchange capacity. - 4) Ion selectivity and gas barrier properties; When immersed in 10 mol / L KOH solution at 80℃, the anion exchange membrane prepared in this invention exhibits excellent durability, with its 28-day tensile strength decay rate being significantly lower than that of commercially available anion exchange membranes. TM SELEMION AMWE-1091 fully demonstrates that the anion exchange membrane prepared by this invention possesses excellent corrosion resistance and durability. The above data confirms that the anion exchange membrane described in this invention has excellent overall performance and can meet the technical requirements of AEM hydrogen electrolyzers.

[0048] Based on the data from the vanadium battery and hydrogen electrolyzer experiments in Examples 1-3, it is determined that when the feed ratio of monomer X to styrene monomer is within the scope of protection of this invention (1-4):1, the prepared anion exchange membrane exhibits excellent comprehensive performance. That is, it possesses both high mechanical properties and durability, while also ensuring high electrochemical performance of the vanadium battery or electrolyzer. In contrast, in Comparative Examples 1 and 2, the feed ratio is outside the constraints of this invention, resulting in a significant decrease in mechanical properties, and other properties are also affected to some extent. Among these, the anion exchange membranes prepared in the comparative examples show better individual properties (such as the corrosion resistance of the membrane prepared in Comparative Example 2), but this is insufficient to compensate for the deficiencies in other properties (such as mechanical properties). Therefore, the performance of the prepared anion exchange membranes needs to be comprehensively considered.

[0049] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing a high molecular polymer, characterized by, Includes the following steps: (1) A copolymer A of the two monomers is obtained by copolymerizing tetraphenylethylene-vinyl monomer and styrene monomer by solution polymerization, wherein the molar ratio of tetraphenylethylene-vinyl monomer to styrene monomer is (1-4):1; (2) Dissolve copolymer A in anhydrous dichloromethane to obtain a solution with a concentration of 10-20 wt%. Add a slight excess of paraformaldehyde and 0.8-1.0 equivalent of catalyst. Then gradually add an anhydrous dichloromethane solution with a concentration of 10-20 wt% of a slight excess of trimethylchlorosilane to the above reaction system. Keep the reaction temperature at 35-40℃. After the dropwise addition reaction is completed, continue stirring the reaction at 35-40℃ for 16-36 h. After the reaction is completed, the copolymer B after chloromethylation is obtained by treatment. (3) Dissolve copolymer B in anhydrous dichloromethane, add trimethylamine aqueous solution containing excess trimethylamine, stir at room temperature for more than 24 hours, and after the reaction is completed, obtain polymer C by treatment.

2. The method of claim 1, wherein the high molecular polymer is prepared by the process of claim 1. In step (1), the endpoint of the solution polymerization reaction is determined by the residual amount of double bond hydrogen <1%. If the residual amount of double bond hydrogen is <1%, the monomer conversion rate is ~100%. The molar ratio of the two monomers corresponding to the structural units in the obtained copolymer A is the molar ratio of the two monomers at the initial feeding.

3. The method for preparing the polymer according to claim 1, characterized in that, The catalyst in step (2) is either SnCl4 or ZnCl2.

4. The method for preparing the polymer according to claim 1, characterized in that, In steps (2) and (3), "slight excess" refers to 1.1-1.2 times the total number of moles, and "excess" refers to 2-3 times the total number of moles.

5. A polymer, characterized in that, The polymer C, prepared according to any one of claims 1-4, has the molecular structure shown in Formula I: Formula I.

6. An anion exchange membrane, characterized in that, Includes the polymer C as described in claim 5.

7. The anion exchange membrane according to claim 6, characterized in that, The method also includes the following steps: dissolving the polymer C in a polar high-boiling-point solvent to form a solution, and then preparing an anion exchange membrane by solution casting.

8. The anion exchange membrane according to claim 7, characterized in that, The polar high-boiling-point solvent is one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

9. An application of an anion exchange membrane in a flow battery, characterized in that, The anion exchange membrane is the anion exchange membrane according to any one of claims 6-8, which can be used in vanadium redox flow battery systems and can also be used in other flow battery systems.

10. The application of an anion exchange membrane in a hydrogen electrolyzer, characterized in that, The anion exchange membrane is the anion exchange membrane according to any one of claims 6-8, and is used in an AEM hydrogen electrolyzer.

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