A branched polyarylpiperidine anion exchange membrane and a method of making the same

Abstract

The application belongs to the technical field of anion exchange membranes, and relates to a branched polyaryl piperidine anion exchange membrane and a preparation method thereof. The branched polyaryl piperidine anion exchange membrane introduces a bulky four-functional group 9,9-bis[6-(2-alkoxy)naphthyl]fluorene, which is polymerized with an aryl monomer and a piperidone and is quaternized to form the anion exchange membrane. The anion exchange membrane has high conductivity, good mechanical properties and chemical stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of anion exchange membranes, and relates to a branched polyaryl piperidine anion exchange membrane and a preparation method thereof. BACKGROUND

[0002] With the development of new energy, hydrogen energy technology has become a key link. Hydrogen energy technology includes three fields of hydrogen production, hydrogen storage and hydrogen use. In the field of water electrolysis hydrogen (green hydrogen) by renewable energy, compared with the conventional proton exchange membrane system using noble metal catalyst, the anion exchange membrane system can use non-noble metal catalyst, and has the advantage of low cost.

[0003] The anion exchange membrane is one of the core components of anion exchange membrane water electrolysis (AEMWE), and plays a role in transmitting hydroxyl ions and separating positive and negative electrodes. The conductivity, mechanical stability and chemical stability of the anion exchange membrane have a crucial influence on the performance of the AEMWE system. At present, the research on the anion exchange membrane shows that the main chain of the non-ether oxygen bond structure has high alkali stability. Among them, the polyaryl piperidine onium anion exchange membrane has been widely concerned due to its simple synthesis process, easy to control structure, good alkali resistance and high mechanical performance. However, the comprehensive performance of the polyaryl piperidine onium anion exchange membrane has not yet met the requirements of the large-scale industrial manufacturing of AEMWE. SUMMARY

[0004] The application aims to solve the problems of the anion exchange membrane in terms of conductivity, mechanical performance and chemical stability, and provides a branched polyaryl piperidine onium anion exchange membrane and a preparation method thereof.

[0005] A branched polyaryl piperidine onium anion exchange membrane has the following structural formula:

[0006]

[0007] In the formula, Ar is an aromatic group, x is the molar percentage of 9,9-bis[6-(2-alkoxy)naphthyl]fluorene and Ar, and x = 1-6. R is methyl or ethyl, and R can be the same or different.

[0008] Ar is one or more than two of the following groups, and Ar can be the same or different:

[0009]

[0010] A preparation method of a branched polyaryl piperidine onium anion exchange membrane comprises the following steps:

[0011] Step (1) Synthesis of 9,9-bis[6-(2-alkoxy)naphthyl]fluorene: 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) is dissolved in organic solvent A at room temperature, potassium carbonate is added, and methyl iodide or ethyl iodide is added, and the reaction is carried out in the dark for 12-48 hours, wherein the molar ratio of 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) to potassium carbonate is 1:(2-6), and the molar ratio of 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) to methyl iodide or ethyl iodide is 1:(2-8). Then, the reaction solution is poured into an ice-water mixture, the precipitate is filtered, washed with water until neutral, and dried in an oven at 50-90°C for 10-24 hours to obtain 9,9-bis[6-(2-alkoxy)naphthyl]fluorene.

[0012] Step (2) Synthesis of branched polyaryl piperidine: 9,9-bis[6-(2-alkoxy)naphthyl]fluorene prepared in step (1) and aryl Ar monomer are placed in organic solvent B at a molar ratio of 0.01:0.99-0.06:0.94, and then N-methyl-4-piperidone is added, and the molar ratio of N-methyl-4-piperidone to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (1.1-1.4):1, and stirring is carried out at 0-25°C for 15-45 minutes; then trifluoroacetic acid and trifluoromethanesulfonic acid are added dropwise at -15-5°C, and the molar ratio of trifluoroacetic acid to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (0.5-1.5):1, and the molar ratio of trifluoromethanesulfonic acid to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (8-11):1, and the reaction is carried out for 6-12 hours, and then the reaction solution is poured into 1 mol / L KOH solution, filtered to obtain fibrous polymer, and then soaked in 1 mol / L potassium carbonate solution for 12-24 hours, filtered, washed with deionized water until neutral, and the obtained polymer is dried in a vacuum oven at 60-90°C for at least 24 hours. -1 -1

[0013] Step (3) Methylation (quaternization): The polymer obtained in step (2) is dispersed in organic solvent A at 50-80°C, and then methyl iodide and potassium carbonate are added, and the molar ratio of methyl iodide to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (1-4):1, and the molar ratio of potassium carbonate to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (1-3):1, and the reaction is carried out in the dark at room temperature for 24-48 hours. When the reaction is completed, the reaction solution is poured into solvent C to precipitate, filtered, the precipitate is washed with solvent C, and then washed with deionized water, filtered, and dried to obtain a quaternary ammonium polymer. ​​

[0014] Step (4) Preparation of anion exchange membrane: the quaternary ammonium polymer obtained in step (3) is dissolved in solvent A, dissolved, filtered with a 0.45 um microporous filter to obtain a casting solution, then cast into a film, and the film is soaked in a 1 mol·L -1 of potassium hydroxide solution at room temperature to 80℃ for 24 to 48 hours, washed with deionized water to neutral, to obtain a branched polyarylpiperidinium anion exchange membrane.

[0015] The organic solvent A is one or more of dimethyl sulfoxide (DMSO), N-methyl pyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC) or a mixture of two or more thereof.

[0016] The organic solvent B is one or more of dichloromethane (DCM), trichloromethane, carbon tetrachloride, dichloroethane or a mixture of two or more thereof.

[0017] The solvent C is one or more of ethyl acetate, diethyl ether, ethanol or a mixture of two or more thereof.

[0018] The aryl Ar monomer is one or more of:

[0019] or a mixture of two or more thereof.

[0020] The 9,9-bis[6-(2-alkoxy)naphthyl]fluorene is one or more of:

[0021] or a mixture of two or more thereof.

[0022] The beneficial effects of the present application are:

[0023] (1) The present application synthesizes a 9,9-bis[6-(2-alkoxy)naphthyl]fluorene tetrafunctional monomer, and a new type of branched polyarylpiperidinium anion exchange membrane is prepared using the monomer. Through the branched structure, the chemical stability and mechanical stability of the membrane are improved.

[0024] (2) The OH - conductivity of the branched polyarylpiperidinium anion exchange membrane of the present application is >100 mS·cm-1@80℃, the tensile strength is >50 MPa, the elongation at break is >10% (dry state), and it has good mechanical properties.

[0025] (3) In the anion exchange membrane electrolysis water test of non-noble metal catalyst, the 500mA·cm -2 @60℃ durability test has exceeded 1000 hours. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1are the mechanical property test results of branched anion exchange membranes prepared based on Examples 2-5 and comparative experiments.

[0027] Figure 2 are the conductivity changes with temperature of branched anion exchange membranes prepared based on Examples 2-5 and comparative experiments.

[0028] Figure 3 are the polarization curves of branched anion exchange membranes prepared in Example 5 on alkaline electrolytic water devices, which can be seen that the membranes have high performance.

[0029] Figure 4 are the durability test results of branched anion exchange membranes prepared in Example 5 on alkaline electrolytic water devices, which show that the membranes have good chemical stability. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are further illustrated in the following with reference to the accompanying drawings and technical solutions.

[0031] The equipment and test methods involved in the examples are as follows:

[0032] Conductivity test: the electrochemical workstation used is PARSTAT4000 of Princeton Applied Research Company. Electrochemical impedance spectroscopy (EIS) is used for measurement, the potential amplitude is 10 mV, and the frequency range is 1 Hz-1 MHz. The membrane is cut into 10 mmX40 mm for testing in a fully wet state, and the temperature is measured every 10℃ from 30-80℃. To ensure the error caused by thermal response, each temperature point is tested after keeping for 30 minutes. The formula for calculating the ionic conductivity of the sample is: σ=L / (RS), (S·cm -1 ), wherein L is the length of the membrane between the electrodes, S is the cross-sectional area of the membrane, S=wd, w (cm) is the width of the membrane, d is the thickness of the membrane (cm), and R is the membrane resistance (Ω).

[0033] Mechanical property test: the prepared anion exchange membrane is placed in a vacuum oven at 80℃ for drying for 24 hours, and then taken out to test according to the test conditions for the determination of tensile properties of plastics Part 3 Test conditions for films and sheets of GBT1040.3-2006, and a type 2 sample is used. The anion exchange membrane is cut into a standard size rectangular sample with a size of 1 cmX15 cm. The test is performed on an INSTRON 3367 electronic universal material testing machine, and the tensile rate is 10 mm·min -1 .

[0034] Electrolytic water performance test: the catalyst is a self-made nanoscale non-noble metal catalyst, and the specific anode is Ni-Fe and the cathode is Ni, and the loading is 2.2 mg·cm -2The self-made ionomer was mixed and bonded on the nickel felt, and the feeding flow of KOH was 3 mL·min -1 .

[0035] Example 1

[0036] Synthesis of 9,9-bis[6-(2-methoxy)naphthyl]fluorene (BMNF): 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) (4.50 g, 10 mmol) was placed in a single-necked flask at room temperature, dissolved in N,N-dimethylformamide to form a 6% wt solution, and iodomethane (7.1 g, 50 mmol), potassium carbonate (6.1 g, 44 mmol) were added. The solution was stirred and reacted in the dark for 24 hours. Then the reaction solution was poured into an excess of ice water mixture, filtered, and washed with water until neutral. The product was dried in a vacuum oven at 80°C for 24 hours to obtain BMNF.

[0037] Example 2

[0038] Preparation of branched polyaryl piperidinium anion exchange membrane (PTPFQ-1):

[0039] (1) Parylene (6.84 g, 29.7 mmol), BMNF (0.14 g, 0.3 mmol) synthesized in Example 1, N-methyl-4-piperidone (4.5 mL, 38.7 mmol) were added to a long-necked flask with mechanical stirring device, and then solvent dichloromethane 40 mL was added. Stirring at 0°C for 30 minutes, then trifluoroacetic acid (3.3 mL, 41.8 mmol), trifluoromethanesulfonic acid (22.6 mL, 22.5 mmol) were added dropwise to the solution. After 9 hours of reaction, the reaction solution was poured into an excess of 1 mol·L -1 Potassium hydroxide solution, filtered, and the fibrous polymer was crushed. After soaking in 1M potassium carbonate for 24 hours, it was filtered, washed with deionized water until neutral, and dried in a vacuum oven at 80°C for 24 hours to obtain PTPF-1.

[0040] (2) Synthesis of PTPFQ-1: PTPF-1 (3 g) was dispersed in DMSO (100 mL) with slight stirring, and potassium carbonate (1.3 g), iodomethane (3 mL) were added. The solution was stirred and reacted in the dark for 24 hours. Then the reaction solution was poured into an excess of ethyl acetate, filtered, and the precipitate was washed with deionized water until neutral. The product was dried in a vacuum oven at 80°C for 24 hours to obtain PTPFQ-1.

[0041] (3) Preparation of PTPFQ-1 anion exchange membrane: PTPFQ-1 was dissolved in DMSO to form a 6 wt% solution, which was cast on a glass plate and dried at 80°C for 12 hours to form a film, and then placed in a vacuum oven at 120°C for 24 hours to remove residual solvent. The film was removed from the glass plate and soaked in 1 mol·L-1 The PTPF-3 was then immersed in 1 mol L potassium hydroxide solution at 80 °C for 48 hours, washed with deionized water for several times, and stored in deionized water for future use.

[0042] Example 3

[0043] Preparation of branched polyarylpiperidinium anion exchange membrane (PTPFQ-3):

[0044] (1) m-Terphenyl (6.70 g, 29.1 mmol), BMNF (0.43 g, 0.9 mmol) synthesized in Example 1, N-methyl-4-piperidone (4.2 mL, 36 mmol) were added into a long neck flask with mechanical stirring device, then solvent dichloromethane 40 mL was added. Stirring at 0 °C for 30 minutes, then trifluoroacetic acid (3.8 mL, 42 mmol), trifluoromethanesulfonic acid (27 mL, 0.305 mol) were added dropwise into the solution. After 6 hours of reaction, the reaction solution was poured into excess 1 mol L potassium hydroxide solution, filtered, the fibrous polymer was broken, soaked in 1 M potassium carbonate for 24 hours, filtered, washed with deionized water until neutral, dried in a vacuum oven at 80 °C for 24 hours to obtain PTPF-3. -1 The PTPF-3 was then immersed in 1 mol L potassium hydroxide solution at 80 °C for 48 hours, washed with deionized water for several times, and stored in deionized water for future use.

[0045] (2) Synthesis of PTPFQ-3: PTPF-3 (3 g) was dispersed in NMP (100 mL) with slight stirring, potassium carbonate (2.5 g, 18 mmol), iodomethane (2.2 mL, 35 mmol) were added, and the reaction was carried out under stirring and light shielding for 24 hours. Then the reaction solution was poured into excess ether, filtered, the precipitate was washed with deionized water at 60 °C until neutral, and dried in a vacuum oven at 80 °C for 24 hours to obtain PTPFQ-3.

[0046] (3) Preparation of PTPFQ-3 anion exchange membrane: PTPFQ-3 was dissolved in DMSO to form a 6 wt% solution, the solution was cast on a glass plate, dried at 80 °C for 12 hours to form a film, and then placed in a vacuum oven at 120 °C for 24 hours to remove residual solvent. The film was removed from the glass plate, immersed in 1 mol L potassium hydroxide solution at 80 °C for 48 hours, washed with deionized water for several times, and stored in deionized water for future use. -1 The PTPF-3 was then immersed in 1 mol L potassium hydroxide solution at 80 °C for 48 hours, washed with deionized water for several times, and stored in deionized water for future use.

[0047] Example 4

[0048] Preparation of branched polyarylpiperidinium anion exchange membrane (PTPFQ-3):

[0049] (1) Biphenyl (4.44 g, 28.8 mmol), BMNF (0.57 g, 1.2 mmol) synthesized in Example 1, N-methyl-4-piperidone (3.9 mL, 33.5 mmol) were added to a long neck flask with mechanical stirring device, then solvent dichloroethane 40 mL was added. Stirring at 0°C for 30 minutes, then trifluoroacetic acid (1.2 mL, 16 mmol), trifluoromethanesulfonic acid (26 mL, 0.29 mol) was added dropwise to the solution. After 6 hours of reaction, the reaction solution was poured into excess 1 mol / L potassium hydroxide solution, filtered, the fibrous polymer was broken, soaked in 1 M potassium carbonate for 48 hours, filtered, washed with deionized water until neutral, dried in a vacuum oven at 80°C for 24 hours to obtain PDPF-4. -1 hydroxide solution, filtered, the fibrous polymer was broken, soaked in 1 M potassium carbonate for 48 hours, filtered, washed with deionized water until neutral, dried in a vacuum oven at 80°C for 24 hours to obtain PDPF-4.

[0050] (2) Synthesis of PDPFQ-4: PDPF-4 (3 g) was dispersed in NMP (100 mL), with slight stirring, potassium carbonate (4.9 g, 35.5 mmol), iodomethane (1.5 mL, 24.1 mmol) was added, stirring and avoiding light for 48 hours. Then the reaction solution was poured into excess ethanol, filtered, the precipitate was washed with deionized water, dried in a vacuum oven at 80°C for 24 hours to obtain PDPFQ-4.

[0051] (3) Preparation of PDPFQ-4 anion exchange membrane: PDPFQ-4 was dissolved in DMAC to form a 6 wt% solution, the solution was cast on a glass plate, dried at 80°C for 12 hours to form a film, then placed in a vacuum oven at 120°C for 24 hours to remove residual solvent. The film was removed from the glass plate, soaked in 1 mol / L potassium hydroxide solution at 80°C for 48 hours, washed with deionized water several times, then stored in deionized water in a sealed container for standby. -1 hydroxide solution, filtered, the fibrous polymer was broken, soaked in 1 M potassium carbonate for 48 hours, filtered, washed with deionized water until neutral, dried in a vacuum oven at 80°C for 24 hours to obtain PDPF-4.

[0052] Example 5

[0053] Preparation of branched polyaryl piperidinium anion exchange membrane (PDPEFQ-6):

[0054] (1) Biphenyl (4.44 g, 28.8 mmol), BMNF (0.57 g, 1.2 mmol) synthesized in Example 1, N-methyl-4-piperidone (3.9 mL, 33.5 mmol) were added to a long neck flask with mechanical stirring device, then solvent dichloroethane 40 mL was added. Stirring at 0°C for 30 minutes, then trifluoroacetic acid (1.2 mL, 16 mmol), trifluoromethanesulfonic acid (26 mL, 0.29 mol) was added dropwise to the solution. After 6 hours of reaction, the reaction solution was poured into excess 1 mol / L potassium hydroxide solution, filtered, the fibrous polymer was broken, soaked in 1 M potassium carbonate for 48 hours, filtered, washed with deionized water until neutral, dried in a vacuum oven at 80°C for 24 hours to obtain PDPF-4. -1The fibrous polymer was broken up, soaked in 1 M potassium carbonate for 24 hours, filtered, washed with deionized water until neutral, and dried in a vacuum oven at 80°C for 24 hours to obtain PDPEF-6.

[0055] (2) Synthesis of PDPEFQ-6: PDPEF-6 (3 g) was dispersed in DMF (100 mL) with slight stirring, and potassium carbonate (4.4 g, 31.7 mmol) and iodomethane (2.0 mL, 31.7 mmol) were added. The reaction was stirred in the dark for 24 hours. The reaction solution was then poured into excess ethyl acetate, filtered, and the precipitate was washed with deionized water until neutral. The precipitate was dried in a vacuum oven at 80°C for 24 hours to obtain PDPEFQ-6.

[0056] (3) Preparation of PDPEFQ-6 anion exchange membrane: PDPEFQ-6 was dissolved in DMSO to form a 6 wt% solution, which was cast on a glass plate and dried at 80°C for 12 hours to form a film. The film was then placed in a vacuum oven at 120°C for 24 hours to remove residual solvent. The film was removed from the glass plate and soaked in a 1 mol·L -1 -1 solution of potassium hydroxide at 80°C for 48 hours. After washing with deionized water several times, the film was stored in deionized water in a sealed container for later use.

[0057] Comparative Experiment

[0058] The comparative experiment used a poly(bisbenzimidazolium) anion exchange membrane that did not contain the BMNF monomer. The preparation method was as follows:

[0059] (1) Bisbenzyl (5.47 g, 30 mmol) and N-methyl-4-piperidone (4.2 mL, 36.1 mmol) were added to a long-necked flask with a mechanical stirring device, followed by the addition of solvent dichloromethane 40 mL. At 0°C, the solution was stirred for 30 minutes, and then trifluoroacetic acid (2.3 mL, 30.0 mmol) and trifluoromethanesulfonic acid (38 mL) were added dropwise. After 6 hours of reaction, the reaction solution was poured into excess 1 mol·L -1 -1 solution of potassium hydroxide, filtered, and the fibrous polymer was broken up. The polymer was soaked in 1 M potassium carbonate for 24 hours, filtered, washed with deionized water until neutral, and dried in a vacuum oven at 80°C for 24 hours to obtain PDPEF-0.

[0060] (2) Synthesis of PDPEFQ-0: PDPEF-0 (3 g) was dispersed in DMSO (100 mL) with slight stirring, and potassium carbonate (3.0 g, 21.6 mmol) and iodomethane (2 mL, 32.4 mmol) were added. The reaction was stirred in the dark for 24 hours. The reaction solution was then poured into excess ethyl acetate, filtered, and the precipitate was washed with deionized water until neutral. The precipitate was dried in a vacuum oven at 80°C for 24 hours to obtain PDPEFQ-0.

[0061] (3) Preparation of PDPEFQ-0 anion exchange membrane: PDPEFQ-0 was dissolved in DMF to form a 6wt% solution, the solution was cast on a glass plate, dried at 80°C for 12 hours to form a film, and then placed in a vacuum oven at 120°C for 24 hours to remove residual solvent. The film was removed from the glass plate, soaked in a 1 mol·L -1 -1 solution of potassium hydroxide at 80°C for 48 hours, washed with deionized water several times, and then stored in deionized water in a sealed container for later use.

[0062] The mechanical property test results of the branched anion exchange membranes prepared based on examples 2-5 and the comparative experiment are shown in Figure 1 From the figure, it can be seen that as the content of 9,9-bis[6-(2-methoxy)naphthyl]fluorene tetrafunctional monomer increases, the elongation at break decreases and the stress increases.

[0063] The conductivity of the branched anion exchange membranes prepared based on examples 2-5 and the comparative experiment as a function of temperature is shown in Figure 2 From the figure, it can be seen that as the content of 9,9-bis[6-(2-methoxy)naphthyl]fluorene tetrafunctional monomer increases, the free volume of the membrane increases, the conductivity increases, and reaches 108 mS·cm -1 -1.

[0064] The polarization curve of the branched anion exchange membrane prepared in example 5 in an alkaline electrolytic water device is shown in Figure 3 It can be seen that the membrane has high performance, and the current density reaches 3 A·cm -2 -1 at 2V.

[0065] The durability test results of the branched anion exchange membrane prepared in example 5 in an alkaline electrolytic water device are shown in Figure 4 It shows that the membrane has good chemical stability, and the voltage is significantly increased after 1000 hours compared with the beginning.

Claims

1. A method for preparing a branched polyarylpiperidine anion exchange membrane, characterized by, Comprising the following steps: Step (1) synthesis of 9,9-bis[6-(2-alkyloxy)naphthyl]fluorene: 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) is dissolved in organic solvent A at room temperature, potassium carbonate is added, and methyl iodide or ethyl iodide is added, and the reaction is carried out in the dark for 12-48 hours, wherein the molar ratio of 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) to potassium carbonate is 1:(2-6), and the molar ratio of 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) to methyl iodide or ethyl iodide is 1:(2-8); then, the reaction solution is poured into an ice-water mixture, the precipitate is filtered, washed with water until neutral, and dried in an oven at 50-90°C for 10-24 hours to obtain 9,9-bis[6-(2-alkyloxy)naphthyl]fluorene; Step (2) Synthesis of branched polyarylpiperidine: 9,9-bis[6-(2-alkoxy)naphthyl]fluorene and aryl Ar monomers prepared in step (1) are placed in organic solvent B at a molar ratio of 0.01:0.99~0.06:0.

94. Then, N-methyl-4-piperidinone is added. The molar ratio of N-methyl-4-piperidinone to 6,6-(9H-fluorene-9,9-diyl)bis(naphthyl-2-ol) in step (1) is (1.1~1.4):

1. Stir at 25℃ for 15-45 minutes; then add trifluoroacetic acid and trifluoromethanesulfonic acid dropwise at -15~5℃, wherein the molar ratio of trifluoroacetic acid to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalene-2-ol) in step (1) is (0.5~1.5):1, and the molar ratio of trifluoromethanesulfonic acid to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalene-2-ol) in step (1) is (8~11):

1. After reacting for 6~12 hours, pour the reaction solution into 1 mol·L -1 The polymer was filtered through a KOH solution to obtain fibrous polymer, which was then reacted with 1 mol·L⁻¹ water. -1 Soak the polymer in potassium carbonate solution for 12-24 hours, filter, wash with deionized water until neutral, and dry the obtained polymer in a vacuum oven at 60-90°C for at least 24 hours. Step (3) quaternization: the polymer obtained in step (2) is dispersed in organic solvent A at 50-80°C, then methyl iodide and potassium carbonate are added, wherein the molar ratio of methyl iodide to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (1-4):1, the molar ratio of potassium carbonate to 6,6-(9H-fluorene-9,9-diyl)bis(naphthalen-2-ol) in step (1) is (1-3):1, and the reaction is carried out in the dark at room temperature for 24-48 hours; at the end of the reaction, the reaction solution is poured into solvent C to precipitate, filtered, the precipitate is washed with solvent C, then washed with deionized water, filtered, and dried to obtain a quaternary ammonium polymer; Step (4) Preparation of anion exchange membrane: the quaternary ammonium polymer obtained in step (3) is dissolved in solvent A, dissolved, filtered with a 0.45 um microporous filter to obtain a casting solution, then cast into a film, and the film is soaked in a 1 mol·L -1 of potassium hydroxide solution at room temperature to 80℃ for 24 to 48 hours, washed with deionized water to neutral, to obtain a branched polyarylpiperidinium anion exchange membrane.

2. The method for preparing a branched polyarylpiperidine anion exchange membrane according to claim 1, characterized in that, The aryl Ar monomer is: one or more of the following:

3. The method for preparing a branched polyarylpiperidine anion exchange membrane according to claim 1 or 2, characterized in that, The 9,9-bis[6-(2-alkyloxy)naphthyl]fluorene is: one or both of the mixtures.

4. The method for preparing a branched polyarylpiperidine anion exchange membrane according to claim 1 or 2, characterized in that, The organic solvent A is one or a mixture of two or more of dimethyl sulfoxide (DMSO), N-methyl pyrrolidone (NMP), N,N-dimethylformamide (DMF), and N,N-dimethylacetamide (DMAC).

5. A method for preparing a branched polyarylpiperidine anion exchange membrane according to claim 1 or 2, characterized in that, The organic solvent B is one or a mixture of two or more of dichloromethane (DCM), trichloromethane, carbon tetrachloride, and dichloroethane.

6. A method for preparing a branched polyarylpiperidine anion exchange membrane according to claim 1 or 2, characterized in that, The solvent C is one or a mixture of two or more of ethyl acetate, diethyl ether, and ethanol.

Images