A high-resistivity vanadium-polyamide composite ion exchange membrane, its preparation method and application

Abstract

This invention relates to the field of flow battery membrane technology, and discloses a high-vanadium-barrier polyamide composite ion exchange membrane, its preparation method, and its applications. The method includes the following steps: preparing a casting solution containing perfluorosulfonic acid resin, amine monomers, and an acid-binding agent, as well as an organic phase solution; preparing a porous ion exchange membrane using a solvent-inducing phase separation method; and preparing the polyamide composite ion exchange membrane through interfacial polymerization. During phase separation, the water-soluble amine monomers and acid-binding agent undergo surface segregation, migrating to the membrane surface and the shallow bulk phase near the surface. The resulting polyamide layer is partially embedded in the main structure of the membrane, enhancing the bonding force between the polyamide layer and the ion exchange membrane and improving stability. The polyamide vanadium-barrier layer possesses nanoscale charged channels, which can improve coulombic efficiency and capacity retention through the dual effects of charge repulsion and pore size sieving.

Description

Technical Field

[0001] This invention relates to the field of flow battery membrane technology, and in particular to a high-resistivity vanadium-containing polyamide composite ion exchange membrane, its preparation method, and its application. Background Technology

[0002] Vanadium redox flow batteries (vanadium batteries) possess outstanding advantages such as long cycle life, no cross-contamination, high safety, and independent design of power and capacity, making them one of the most promising electrochemical energy storage technologies for large-scale energy storage. Ion exchange membranes, as the core material of vanadium redox flow batteries, primarily function to conduct protons and prevent cross-contamination of vanadium ions in the electrolyte between the positive and negative electrodes. Their ion selectivity, proton conductivity, resistance to strong acid oxidation, dimensional stability, and manufacturing cost directly determine the battery's coulombic efficiency, energy efficiency, capacity retention, and overall cost per kilowatt-hour, representing a key bottleneck restricting the large-scale commercialization of vanadium redox flow batteries.

[0003] Currently, commercially available vanadium redox flow batteries commonly use perfluorosulfonic acid ion exchange membranes (representative products include the Nafion series membranes). These materials possess excellent proton conductivity and chemical stability, making them the most mature membrane products currently in use. However, these membranes suffer from high vanadium ion transmembrane permeability and self-discharge, resulting in insufficient coulombic efficiency for the batteries. To address these issues, existing modification methods in the industry mainly include inorganic nanofiller doping, polymer blending, and surface grafting modification. However, these modification methods are costly, necessitating the development of a low-cost, high-efficiency modification approach to improve the coulombic efficiency of vanadium battery membranes.

[0004] Interfacial polymerization can generate an ultrathin, dense polyamide separation layer in situ on the surface of porous membranes, enabling precise control of membrane pore structure and interfacial charge characteristics. Without significantly increasing membrane surface impedance, it improves ion selectivity through a combination of pore size sieving and charge repulsion. Interfacial polymerization offers advantages such as ease of operation, rapid reaction, and low cost. Its application in the modification of battery separators holds promise for improving the coulombic efficiency, energy efficiency, and capacity retention of vanadium batteries, thereby enhancing their overall performance. Summary of the Invention

[0005] This invention provides a high vanadium-barrier polyamide composite ion exchange membrane, its preparation method, and its application, to solve the problems of poor vanadium-barrier performance, low coulombic efficiency, low energy efficiency, and rapid capacity decay in ion exchange membranes used in vanadium batteries. First, a casting solution is prepared by dissolving perfluorosulfonic acid resin, amine monomers, and an acid-binding agent in an organic solvent. This solution is then evenly spread on a clean glass plate using a doctor blade and immersed in a coagulation bath to undergo phase separation, obtaining the ion exchange membrane. During phase separation, the water-soluble amine monomers and acid-binding agent undergo surface segregation, migrating to the membrane surface and the shallow bulk phase near the surface. Next, after cleaning the ion exchange membrane and drying off any residual water, it is immersed in a solution of polyacrylamide chlorides, where it undergoes interfacial polymerization with the amine monomers on the membrane surface to generate a polyamide vanadium-barrier layer, a portion of which is embedded in the bulk phase of the ion exchange membrane. The acid-binding agent neutralizes the generated hydrochloric acid to promote the reaction in the forward direction, increasing the degree of polymerization. After the reaction, the membrane is subjected to a certain degree of heat treatment to improve the bonding force between the polyamide layer and the ion exchange membrane, ultimately obtaining the polyamide composite ion exchange membrane.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a method for preparing a high-resistivity vanadium-based polyamide composite ion exchange membrane is disclosed, characterized by comprising the following steps: Step S1: Dissolve the perfluorosulfonic acid resin, amine monomers and acid-binding agent in organic solvent 1, let stand to remove bubbles, and obtain casting solution; dissolve polyacrylamide chloride in organic solvent 2 to obtain organic phase solution; Step S2: Pour the casting solution onto a glass plate, spread it evenly, and then place it in deionized water for phase separation to obtain a mixed matrix porous membrane; Step S3: Immerse the mixed matrix porous membrane in the organic phase solution to undergo interfacial polymerization. After the reaction is completed, perform heat treatment to obtain a high-vanadium-barrier polyamide composite ion exchange membrane.

[0007] In one implementation, in step S1: The mass fraction of the perfluorosulfonic acid resin in the casting solution is 10%~20%, the mass fraction of the amine monomer is 1%~5%, and the mass fraction of the acid-binding agent is 2%~10%.

[0008] In one implementation, in step S1: The amine monomer is selected from one of m-phenylenediamine, diethylenetriamine, piperazine, o-phenylenediamine, and polyethyleneimine with a molecular weight of 70k; The acid-binding agent is selected from one of triethylamine, tripropylamine, N,N-diisopropylethylamine, pyridine, and N-methylmorpholine.

[0009] Acid-binding agents can neutralize the hydrogen chloride generated by the reaction of amino and acyl chloride groups, inhibit the reverse reaction, prevent the protonation and deactivation of raw materials, and avoid acidification of the system from affecting the polymerization reaction.

[0010] In one implementation, in step S1: The mass fraction of polyacrylamide chloride in the organic phase solution is 0.5% to 2.5%.

[0011] In one implementation, in step S1: The polyacrylic chloride is selected from one of pyromellitic methyl methacrylate, adipoxyethyl chloride, isophthaloyl chloride, and terephthaloyl chloride.

[0012] Polyacyl chlorides react rapidly with amine monomers on the membrane surface and in the shallow layer to form a polyamide layer. The hydrochloric acid generated is neutralized by the acid-binding agent, making the reaction more complete.

[0013] In one implementation, in step S1: The organic solvent 1 is selected from dimethyl sulfoxide, acetone, tetrahydrofuran, dichloromethane, and N-methylpyrrolidone; The organic solvent 2 is selected from one of n-hexane, n-heptane, cyclohexane, cyclopentane, and isododecane (Isopar G).

[0014] Choosing a nonpolar solvent can significantly reduce the swelling of the ion exchange membrane.

[0015] In one implementation, in step S2: The method for uniformly spreading the coating solution is to use a coating machine and adjust the height of the scraper of the coating machine to 50~200μm to uniformly coat the casting solution onto the glass plate. The phase separation time is 20~100s.

[0016] In one implementation, in step S3: The time for the interfacial polymerization reaction is 1~5 min; The heat treatment temperature is 60~100℃ and the time is 1~5min.

[0017] Secondly, a high-resistivity vanadium-based polyamide composite ion exchange membrane is disclosed, which is prepared by the above-described method for preparing a high-resistivity vanadium-based polyamide composite ion exchange membrane.

[0018] Thirdly, an application of a high-resistivity vanadium-polyamide composite ion exchange membrane is disclosed. The high-resistivity vanadium-polyamide composite ion exchange membrane prepared by the above-described method, or the above-described high-resistivity vanadium-polyamide composite ion exchange membrane, is applied to vanadium batteries; wherein, The high-resistivity vanadium polyamide composite ion exchange membrane has a coulombic efficiency of not less than 99.1% in the vanadium battery; The high-resistivity vanadium polyamide composite ion exchange membrane has an energy efficiency of not less than 84.9% in the vanadium battery; The high-resistivity vanadium polyamide composite ion exchange membrane retains no less than 80% of its capacity after 200 cycles in the vanadium battery.

[0019] The beneficial effects of this invention are as follows: 1. Simplify the traditional interfacial polymerization process and improve preparation efficiency. Reduce the number of solvent soaking times and shorten the soaking time, mitigating the decrease in vanadium barrier properties of the ion-exchange membrane caused by swelling.

[0020] 2. Using phase separation instead of casting and heating allows the aqueous polyimide to accumulate on the surface of the ion exchange membrane and in the shallow bulk phase. The resulting polyamide layer is partially embedded in the main structure of the membrane, enhancing the bonding force between the polyamide layer and the ion exchange membrane and improving stability.

[0021] 3. Adding an acid-binding agent can neutralize the hydrochloric acid generated during interfacial polymerization, inhibit side reactions and reverse reactions, and improve the efficiency of interfacial polymerization.

[0022] 4. The polyamide vanadium barrier layer has nano-sized charged channels, which can improve coulombic efficiency and capacity retention through the dual effects of charge repulsion and pore size sieving. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a method for preparing a high-resistivity vanadium-containing polyamide composite ion exchange membrane according to the present invention; Figure 2 These are electron micrographs of the high-vanadium-resistance polyamide composite ion exchange membranes in Example 1 and Comparative Example 1 of the present invention. Figure 3 This is a graph showing the coulombic efficiency and capacity retention of the high-resistivity vanadium-based polyamide composite ion exchange membrane in Example 2 of the present invention as a function of the number of test cycles. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0025] like Figure 1 As shown, a method for preparing a high-resistivity vanadium-based polyamide composite ion exchange membrane includes the following steps: Step S1: Preparation of casting solution and organic phase solution: Dissolve perfluorosulfonic acid resin, amine monomers, and acid-binding agent in organic solvent 1, allow to stand to remove bubbles, and obtain casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 10%~20%, the mass fraction of amine monomers is 1%~5%, and the mass fraction of acid-binding agent is 2%~10%. Dissolve polyacrylamide chloride in organic solvent 2 to obtain organic phase solution, the mass fraction of which is 0.5%~2.5%. The amine monomer is selected from m-phenylenediamine, diethylenetriamine, piperazine, o-phenylenediamine, and polyethyleneimine (molecular weight 70K). The acid-binding agent is selected from triethylamine, tripropylamine, N,N-diisopropylethylamine, pyridine, and N-methylmorpholine. Organic solvent 1 is selected from dimethyl sulfoxide, acetone, tetrahydrofuran, dichloromethane, and N-methylpyrrolidone. The polyacrylic chloride is selected from one of trimesoyl chloride, adipic acid chloride, isophthaloyl chloride, and terephthaloyl chloride. The organic solvent 2 is selected from one of n-hexane, n-heptane, cyclohexane, cyclopentane, and isododecane (Isopar G).

[0026] S2. Preparation of porous ion exchange membrane by non-solvent-induced phase separation method: The casting solution is poured onto a glass plate and spread evenly using a coating machine. Then, it is placed in deionized water for phase separation for 20-100 s to obtain a mixed matrix porous membrane. The doctor blade height of the coating machine is 50-200 μm.

[0027] S3. Preparation of high-vanadium-barrier polyamide composite ion exchange membrane by interfacial polymerization: The mixed matrix porous membrane is immersed in the organic phase solution to undergo an interfacial polymerization reaction for 1-5 minutes. After the reaction, it is heat-treated to obtain the polyamide composite ion exchange membrane. The heat treatment temperature is 60-100℃, and the heat treatment time is 1-5 minutes.

[0028] The mechanism involved in this invention is as follows: 1. A non-solvent-induced phase separation method was used to prepare porous ion-exchange membranes. The ion-exchange membrane preparation process was optimized by using a phase separation method instead of the casting and heating method. This eliminates the need for high-temperature heating, solvent evaporation, and resin crystallization, reducing energy consumption and solvent vapor pollution. The phase separation process allows water-soluble amine monomers to accumulate on the ion-exchange membrane surface and in the shallow bulk phase, exposing more polymerization sites, improving the efficiency of interfacial polymerization, and accelerating the reaction rate. Furthermore, some polyamide is generated in the shallow bulk phase of the ion-exchange membrane, embedding itself into the main structure of the membrane, enhancing the bonding force between the polyamide layer and the ion-exchange membrane, and improving the stability of the composite membrane.

[0029] 2. Selection and Function of Acid-Binding Agents. During interfacial polymerization, the reaction between amine monomers and acyl chlorides generates a large amount of hydrochloric acid, potentially causing the reaction to proceed in the negative direction. Selecting weakly basic small organic molecules can capture hydrochloric acid, reducing the acidity of the system and allowing the reaction to proceed in the positive direction, thus improving reaction efficiency.

[0030] 3. The role of the polyamide vanadium barrier layer. Polyamide has positively charged nano-sized pores, which can hinder the shuttle of vanadium ions through the dual effects of charge repulsion and pore size sieving, thereby improving the coulombic efficiency and capacity retention of vanadium batteries and enhancing the overall performance stability.

[0031] Example 1: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, m-phenylenediamine, and triethylamine in dimethyl sulfoxide, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 10%, the mass fraction of m-phenylenediamine is 1%, and the mass fraction of triethylamine is 2%. Dissolve pyromellitic acid chloride in n-hexane to obtain an organic phase solution with a mass fraction of 0.5%.

[0032] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 100 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 100 μm.

[0033] S3. The porous ion exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 3 minutes. After the reaction, it is heat-treated to obtain a high-resistance vanadium-polyamide composite ion exchange membrane. The heat treatment temperature is 80°C and the heat treatment time is 3 minutes.

[0034] Example 2: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, diethylenetriamine, and tripropylamine in acetone, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 12%, the mass fraction of diethylenetriamine is 2%, and the mass fraction of tripropylamine is 4%. Dissolve pyromellitic acid chloride in n-heptane to obtain an organic phase solution with a mass fraction of 1%.

[0035] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 80 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 150 μm.

[0036] S3. The porous ion exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 4 minutes. After the reaction, it is heat-treated to obtain a high-resistance vanadium-polyamide composite ion exchange membrane. The heat treatment temperature is 60°C and the heat treatment time is 5 minutes.

[0037] Example 3: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, piperazine, and N,N-diisopropylethylamine in tetrahydrofuran, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 15%, the mass fraction of piperazine is 3%, and the mass fraction of N,N-diisopropylethylamine is 5%. Dissolve adipic acid chloride in cyclohexane to obtain an organic phase solution with a mass fraction of 1.5%.

[0038] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 60 seconds to obtain a mixed matrix porous membrane; the blade height of the coating machine is 50 μm.

[0039] S3. The porous ion exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 5 minutes. After the reaction, it is heat-treated to obtain a high-resistance vanadium-polyamide composite ion exchange membrane. The heat treatment temperature is 100℃ and the heat treatment time is 1 minute.

[0040] Example 4: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, o-phenylenediamine, and pyridine in dichloromethane, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 18%, the mass fraction of o-phenylenediamine is 4%, and the mass fraction of pyridine is 8%. Dissolve isophthaloyl chloride in cyclopentane to obtain an organic phase solution with a mass fraction of 2%.

[0041] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 40 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 200 μm.

[0042] S3. The porous ion exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 2 minutes. After the reaction, it is heat-treated to obtain a high-resistance vanadium-polyamide composite ion exchange membrane. The heat treatment temperature is 70°C and the heat treatment time is 4 minutes.

[0043] Example 5: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, polyethyleneimine (molecular weight 70K), and N-methylmorpholine in N-methylpyrrolidone, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 20%, the mass fraction of polyethyleneimine (molecular weight 70K) is 5%, and the mass fraction of N-methylmorpholine is 10%. Dissolve terephthaloyl chloride in isododecane (Isopar G) to obtain an organic phase solution with a mass fraction of 2.5%.

[0044] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 40 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 200 μm.

[0045] S3. The porous ion exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 2 minutes. After the reaction, it is heat-treated to obtain a high-resistance vanadium-polyamide composite ion exchange membrane. The heat treatment temperature is 70°C and the heat treatment time is 4 minutes.

[0046] Comparative Example 1: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin and m-phenylenediamine in dimethyl sulfoxide, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 10% and the mass fraction of m-phenylenediamine is 1%. (That is, no acid-binding agent is added to the casting solution.) Dissolve trimesoyl chloride in n-hexane to obtain an organic phase solution with a mass fraction of 0.5%.

[0047] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 100 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 100 μm.

[0048] S3. The porous ion-exchange membrane from S2 is immersed in the organic phase solution from S1 to undergo an interfacial polymerization reaction for 3 minutes. After the reaction, it is heat-treated to obtain the polyamide composite ion-exchange membrane. The heat treatment temperature is 80°C and the heat treatment time is 3 minutes.

[0049] Comparative Example 2: The following technical solution is adopted. S1. Dissolve perfluorosulfonic acid resin, diethylenetriamine, and tripropylamine in acetone, allow to stand to remove air bubbles, and obtain a casting solution, wherein the mass fraction of perfluorosulfonic acid resin is 12%, the mass fraction of diethylenetriamine is 2%, and the mass fraction of tripropylamine is 4%. Dissolve pyromellitic acid chloride in n-heptane to obtain an organic phase solution with a mass fraction of 1%.

[0050] S2. Pour the casting solution obtained in step S1 onto a glass plate, spread it evenly using a coating machine, and then place it in deionized water for phase separation for 80 seconds to obtain a mixed matrix porous membrane; the doctor blade height of the coating machine is 150 μm.

[0051] Battery performance testing: The membranes from Examples 1-5 and Comparative Examples 1-2 were assembled into battery stacks for testing. Coulombic efficiency, voltage efficiency, energy efficiency, and capacity retention after 200 cycles were tested and recorded under the same operating conditions. The test results are shown in Table 1.

[0052] Table 1 Battery performance test results

[0053] As shown in Table 1 and Figure 2 The performance test results show that the high vanadium-barrier polyamide composite ion exchange membranes prepared in Examples 1-5 achieved an initial coulombic efficiency of over 99% during vanadium battery testing, and maintained a capacity retention rate of over 80% after 200 cycles. This indicates that the polyamide vanadium-barrier layer possesses nanoscale charged channels, which can improve coulombic efficiency and capacity retention through the dual effects of charge repulsion and pore size sieving. The phase separation process allows water-soluble amine monomers to accumulate on the ion exchange membrane surface and in the shallow bulk phase, exposing more polymerization sites, improving the efficiency of interfacial polymerization, and accelerating the reaction rate. Furthermore, some polyamide is generated in the shallow bulk phase of the ion exchange membrane, embedding itself into the main structure of the ion exchange membrane, enhancing the bonding force between the polyamide layer and the ion exchange membrane, and improving the stability of the composite membrane. Compared with the porous ion exchange membrane without a polyamide vanadium-barrier layer in Comparative Example 2, the discharge capacity decay trend of the polyamide composite ion exchange membrane is significantly slower during long-term test cycles, indicating that the simplified interfacial polymerization method provided by this invention can reduce the number of solvent soaking times, shorten the soaking time, and alleviate the decrease in vanadium barrier properties caused by swelling of the ion exchange membrane. Figure 3 The electron micrographs show that the polyamide layer of Example 1 prepared using the acid-binding agent is more uniform, and the degree of reaction is significantly better than that of Comparative Example 1, which does not use the acid-binding agent. Furthermore, the coulombic efficiency of the ion-exchange membrane in Comparative Example 1, which does not contain the acid-binding agent, failed to reach above 99%, and its discharge capacity decreased rapidly. This indicates that adding the acid-binding agent can neutralize the hydrochloric acid generated during interfacial polymerization, suppress side reactions and reverse reactions, and improve the uniformity and efficiency of interfacial polymerization.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-resistivity vanadium-based polyamide composite ion exchange membrane, characterized in that, Includes the following steps: Step S1: Dissolve the perfluorosulfonic acid resin, amine monomers and acid-binding agent in organic solvent 1, let stand to remove bubbles, and obtain casting solution; dissolve polyacrylamide chloride in organic solvent 2 to obtain organic phase solution; Step S2: Pour the casting solution onto a glass plate, spread it evenly, and then place it in deionized water for phase separation to obtain a mixed matrix porous membrane; Step S3: Immerse the mixed matrix porous membrane in the organic phase solution to undergo interfacial polymerization. After the reaction is completed, perform heat treatment to obtain a high-vanadium-barrier polyamide composite ion exchange membrane.

2. The preparation method according to claim 1, characterized in that, In step S1: The perfluorosulfonic acid resin in the casting solution has a mass fraction of 10% to 20%, the amine monomer has a mass fraction of 1% to 5%, and the acid-binding agent has a mass fraction of 2% to 10%.

3. The preparation method according to claim 1, characterized in that, In step S1: The amine monomer is selected from one of m-phenylenediamine, diethylenetriamine, piperazine, o-phenylenediamine, and polyethyleneimine with a molecular weight of 70k; The acid-binding agent is selected from one of triethylamine, tripropylamine, N,N-diisopropylethylamine, pyridine, and N-methylmorpholine.

4. The preparation method according to claim 1, characterized in that, In step S1: The mass fraction of polyacrylamide chloride in the organic phase solution is 0.5% to 2.5%.

5. The preparation method according to claim 1, characterized in that, In step S1: The polyacrylic chloride is selected from one of pyromellitic methyl methacrylate, adipoxyethyl chloride, isophthaloyl chloride, and terephthaloyl chloride.

6. The preparation method according to claim 1, characterized in that, In step S1: The organic solvent 1 is selected from dimethyl sulfoxide, acetone, tetrahydrofuran, dichloromethane, and N-methylpyrrolidone; The organic solvent 2 is selected from one of n-hexane, n-heptane, cyclohexane, cyclopentane, and isododecane.

7. The preparation method according to claim 1, characterized in that, In step S2: The method for uniformly spreading the coating solution is to use a coating machine and adjust the height of the scraper of the coating machine to 50~200μm to uniformly coat the casting solution onto the glass plate. The phase separation time is 20~100s.

8. The preparation method according to claim 1, characterized in that, In step S3: The time for the interfacial polymerization reaction is 1~5 min; The heat treatment temperature is 60~100℃ and the time is 1~5min.

9. A high-resistivity vanadium-based polyamide composite ion exchange membrane, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 8.

10. An application of a high-resistivity vanadium-polyamide composite ion exchange membrane, characterized in that, The high-resistivity vanadium-containing polyamide composite ion exchange membrane prepared by the preparation method according to any one of claims 1 to 8, or the high-resistivity vanadium-containing polyamide composite ion exchange membrane according to claim 9, is applied to vanadium batteries.

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