Azulene-based polybenzimidazole anion exchange membrane, and preparation method and application thereof

Abstract

The application discloses an azulene-based polybenzimidazole anion exchange membrane and a preparation method and application thereof, and belongs to the technical field of membranes. The application provides a novel design idea of polybenzimidazole polymer through polymerization and quaternization reaction, and a series of azulene-based polybenzimidazole basic anion exchange membranes are prepared, including straight and branched types. The introduction of azulene enriches the structure of the polybenzimidazole polymer, and the strong nucleophilicity improves the basic stability of the membrane. In addition, the polybenzimidazole containing the azulene structure has high mechanical strength and thermal stability, the water absorption and the swelling ratio are reduced, and the dimensional stability is improved. The azulene-based polybenzimidazole anion exchange membrane provided by the application has high OH ‑ conductivity, basic stability and high mechanical strength, and can be used as an anion exchange membrane material for alkaline fuel cells and alkaline electrolytic cells.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of membranes, and particularly relates to an azulene-based polybenzimidazole anion exchange membrane and a preparation method and application thereof. BACKGROUND

[0002] Hydrogen is essential for decarbonization and sustainable development. Anion exchange membrane fuel cells (AEMFCs) have attracted much attention due to their independence on expensive noble metal (such as palladium) catalysts and the possibility of using low-alkaline electrolytes. Anion exchange membranes (AEMs) are the key components of AEMFCs and alkaline electrolysis cells. However, the commercialization of AEMs is hindered by the lack of AEMs with excellent comprehensive performance (alkaline stability, dimensional stability and electrical conductivity). The main reason is that the improvement of ion exchange capacity (IEC) and electrical conductivity is often accompanied by high water uptake (WU) and swelling ratio (SR), which directly affects the dimensional stability and mechanical stability of the material, and further affects the service life. Solving this "trade-off" effect is crucial for the development of AEMs.

[0003] Polybenzimidazoles (PBIs) are a class of glassy polymers with benzimidazole units in the repeat unit. They usually exhibit excellent chemical stability, ultra-high thermal stability (up to 400℃), inherent flame retardancy and excellent mechanical properties. In addition, the excellent electrical conductivity of PBIs makes them have great application potential in the direction of proton exchange membranes, and has become a prominent research field. However, PBIs-based materials are not mature in anion exchange membranes, and the main problems of PBIs-based materials in this field are: (1) the "trade-off" effect between anion conductivity and dimensional stability; (2) the problem of short service life due to easy attack by anions in alkaline environment; (3) the limited structure selection makes it more difficult to change the above two performances.

[0004] Azulene, as an isomer of naphthalene, is composed of a fused electron-rich five-membered ring and an electron-deficient seven-membered ring, and has a very large dipole moment (1.08D). This special structure determines the physical and chemical properties of azulene, such as narrow HOMO-LUMO energy gap and anti-kasha fluorescence emission produced by S2 to S0 transition. The strong nucleophilicity of azulene helps to improve the alkaline resistance of polybenzimidazole polymers, and the rich azulene structure and substitution sites can greatly enhance the designability of the material structure, thereby being more conducive to the preparation of target polymers that match the application performance. SUMMARY

[0005] The application provides an azulene-based polybenzimidazole anion exchange membrane, characterized in that the azulene-based polybenzimidazole anion exchange membrane contains an azulene-based polybenzimidazole polymer, and the structure of the azulene-based polybenzimidazole polymer is shown as formula I.

[0006]

[0007] wherein different A represents different types of PBI, B is an aromatic group, C is an azulenyl group, R is a different cationic group, and n has a value between 0.01 and 1.

[0008] The present application also provides a preparation method of the azulenyl polybenzimidazole anion exchange membrane, comprising the following steps:

[0009] (1) Synthesis of azulenyl polybenzimidazole precursor polymer: a dicarboxy aromatic monomer R, a dicarboxy azulenyl monomer B, 3,3'-diaminobenzidine (DAP) or its derivative are loaded into a round bottom flask with a stirrer, an inert gas inlet and a calcium chloride drying tube in a certain proportion. Add organic solvent α, nitrogen purge, and then optionally add a small amount of catalyst β. The resulting mixed solution is stirred and reacted at 140-200°C. After a certain period of reaction, the resulting viscous solution is precipitated by pouring into excess water, and the resulting polymer solid is collected. The solid is neutralized with potassium carbonate solution (pH>7, preferably pH=7-9), and then washed thoroughly with deionized water, and dried at 80°C under vacuum for 24h to obtain azulenyl polybenzimidazole.

[0010] The structure is shown in formula II:

[0011]

[0012] wherein different A represents different types of PBI, B is an aromatic group, C is an azulenyl group, and n has a value between 0.01 and 1.

[0013] (2) Synthesis of cationic azulenyl polybenzimidazole: the azulenyl polybenzimidazole obtained in step 1 is dissolved in organic solvent β, heated to dissolve, and γ is added. Stirring at 80°C for a period of time. The solution after the reaction is poured into water to precipitate, and finally washed with water, filtered, collected and dried at 80°C under vacuum for 24h.

[0014] (3) Preparation of azulenyl polybenzimidazole anion exchange membrane: the cationic azulenyl polybenzimidazole obtained in step 2 is dissolved in an organic solvent, stirred at room temperature and filtered, the filtrate is cast on a clean glass plate, the residual solvent is removed, and then the film is carefully peeled off from the glass plate to obtain Cl - membrane, and then the Cl - membrane is placed in a KOH solution for ion exchange to obtain OH - membrane, and then washed with degassed deionized water under an inert atmosphere to obtain an azulenyl polybenzimidazole anion exchange membrane.

[0015] In a preferred embodiment of the present application, the molar ratio of C to B in step (1) is 1:1-99, and the molar ratio of B+C to DAP (or its derivative) is 1:0.9-1.2.

[0016] In another preferred embodiment of the present application, in step (1), the organic solvent α is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, and polyphosphoric acid.

[0017] In another preferred embodiment of the present application, in step (1), the catalyst is selected from at least one of phosphorus pentoxide, polyphosphoric acid, and methanesulfonic acid.

[0018] In another preferred embodiment of the present application, in step (2), the organic solvent is selected from at least one of acetonitrile, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, or sulfolane.

[0019] The present application also provides an azulene-based polybenzimidazole anion exchange membrane prepared by the preparation method as described above.

[0020] The present application also provides the use of the azulene-based polybenzimidazole anion exchange membrane as described above in the preparation of a fuel cell or an alkaline electrolytic cell.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The present application provides a new design idea of polybenzimidazole polymers by polymerization and quaternization, and a series of azulene-based polybenzimidazole alkaline anion exchange membranes, including linear and branched types, are prepared. The introduction of azulene group enriches the structure of polybenzimidazole polymers, and the strong nucleophilicity improves the alkaline stability of the membrane. In addition, the polybenzimidazole containing azulene group has high mechanical strength and thermal stability, low water absorption and swelling ratio, and improved dimensional stability.

[0023] The azulene-based polybenzimidazole anion exchange membrane provided by the present application exhibits high OH - conductivity, alkaline stability, and high mechanical strength, and can be used as an anion exchange membrane material for alkaline fuel cells and alkaline electrolytic cells.

[0024] After optimization, the azulene-based polybenzimidazole anion exchange membrane of the present application has high OH - conductivity (OH - conductivity > 100 mS cm -1 ), high mechanical strength (tensile strength > 35 MPa, elongation at break > 10%), high dimensional stability, good processing performance, and excellent alkaline stability in 1M KOH at 80℃ (> 500h). BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Graph of test results for water absorption for each example and comparative example;

[0026] Figure 2 Graph of test results for swelling rate for each example and comparative example;

[0027] Figure 3 Graph of test results for electrical conductivity for each example and comparative example;

[0028] Figure 4 Test results for basic electrolyzed water MEA for each example and comparative example. DETAILED DESCRIPTION

[0029] The following further describes the specific embodiments of the application in conjunction with the technical solutions.

[0030] The following are various exemplary embodiments of the present application, which should not be considered as limiting the present application, but rather as a more detailed description of certain aspects, features and embodiments of the present application. It should be understood that the terminology used in the present application is merely for the purpose of describing the particular embodiments and is not intended to limit the present application.

[0031] In addition, for numerical ranges in the present application, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range is also encompassed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described.

[0033] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended terms that are intended to mean including, but not limited to. The synthetic methods used in the present application are conventional synthetic methods in the art, and the product composition structure can be inferred from the starting materials used.

[0034] Test methods used in the following examples:

[0035] Performance tests:

[0036] Equipment and test methods involved in the examples:

[0037] Polymer structure characterization: The proton NMR spectrum of the polymer was measured using an AVANCE III HD 400 (400M) liquid nuclear magnetic resonance spectrometer. 1 H NMR and carbon spectroscopy 13 The infrared spectra of the polymer were measured using a Platinum Elmer Spectrum 100 Fourier Transform Infrared Spectrometer. The molecular weight of the polymer was characterized using a room-temperature gel permeation chromatography system (Z-1601, Tosoh Corporation, Japan).

[0038] Ion exchange capacity (IEC) test method: Br of azulene polybenzimidazole polymer - or I - The membrane was dried in a vacuum oven at 75°C, and its weight was recorded. The membrane was then immersed in 25 mL of 0.2 M NaNO3 solution for 6 hours, repeated three times, and the NaNO3 solution after ion exchange was collected. Potassium chromate solution (20 mL, 0.01 M) was added to this solution, and titrated with 0.01 M AgNO3 standard solution. The titration was complete when a brick-red precipitate appeared and did not disappear after shaking. The volume of AgNO3 solution consumed was recorded. The product of the AgNO3 solution concentration and volume, divided by the mass of the dry membrane, is the IEC (interval between concentration and volume).

[0039] Conductivity Testing: The electrochemical workstation used was a CHI660E manufactured by Shanghai Chenhua Instrument Co., Ltd. The conductivity of the branched membrane at different temperatures was tested using the electrochemical impedance spectroscopy (EIS). The measured potential amplitude was 10 mV. To reduce the error caused by contact resistance, the resistance measured was the in-plane resistance of the membrane sample. In the experiment, the membrane was cut into 40 mm × 10 mm pieces, placed in a fixture, and the fixture was placed in pure water. The test temperature ranged from 30℃ to 80℃, with membrane resistance measured every 10℃. The membrane was kept warm for 1 hour before each test. Finally, the ionic conductivity σ of the sample was calculated using the formula: σ = l / (wdR), where l is the length of the membrane between electrodes (cm), w is the width of the membrane (cm), d is the thickness of the membrane (μm), and R is the measured membrane resistance (mΩ).

[0040] Alkaline fuel cell performance testing: The instrument used was a Scribner Associates Co., Ltd., USA, model 850e multi-range fuel cell testing system, tested in current mode. The test conditions were H2 and O2 atmosphere, test temperature 60℃ and 80℃, and H2 and O2 flow rate 200mL / min.

[0041] Tensile strength test: The dry film sample of 5×0.5cm (length×width) was tested using an Instron M3300 electronic universal testing machine at a tensile rate of 5mm / min.

[0042] Alkaline stability test: The prepared anion exchange membranes were immersed in NaOH solution with different concentrations (1, 2, 5, 10 M) and temperatures (20, 30, 40, 50, 60, 70, 80 °C), and the conductivity was measured at the same time. The alkaline stability of the electrolyte membrane was analyzed by the change of the conductivity of the electrolyte membrane.

[0043] Water electrolysis performance test of anion exchange membrane: the anode was titanium felt loaded with IrO2(1 mg / cm 2 ) and the cathode was carbon paper loaded with Pt / C (1 mg / cm 2 ) with a Pt mass content of 20%, Nafion was used as the conductive agent and adhesive, the content was 0.5wt%, and the electrode area was 4cm 2 . The MEA electrolysis cell was assembled, the electrolyte was 1M KOH, the circulation speed was 20mL / min, and the test temperature was 60°C. The test instrument was CHI660e, and the electrolysis cell was tested by linear voltammetry scanning from 0 to 2V.

[0044] Example 1

[0045] Preparation of 1,3-azulene-based polybenzimidazole (p-PBI-Az-n) anion exchange membrane:

[0046] (1) Synthesis of 1,3-azulene-based polybenzimidazole precursor polymer (p-PBI-Az-n): Taking the synthesis of p-PBI-Az-1 as an example, 3,3'-diaminobenzidine (2.15 g, 10.03 mmol), terephthalic acid (1.65 g, 9.93 mmol), and 1,3-azulene dicarboxylic acid (0.022 g, 0.10 mmol) were placed in a round-bottom flask with a stirrer, an inert gas inlet, and a calcium chloride drying tube. Polyphosphoric acid (83.50 g) was added and nitrogen was purged. The resulting mixed solution was stirred at 180°C for 48h. The resulting viscous solution was poured into 300mL water to precipitate, and the resulting polymer solid was collected. The solid was neutralized with potassium carbonate solution (300mL, 1.0M) (pH=7.4), then washed with deionized water, and dried at 80°C under vacuum for 24h to obtain black solid p-PBI-Az-1 (the structure of the polymer was confirmed by nuclear magnetic resonance and infrared; the weight average molecular weight of the polymer was 24.5kda), y=87% (Yield). Wherein, n=1 means that the content of 1,3-azulene dicarboxylic acid accounts for 10% of the total dicarboxylic monomer content.

[0047]

[0048] (2) Synthesis of functionalized 1,3-azulenyl polybenzimidazole (p-PBI-Az-n-Br): Again, p-PBI-Az-1-Br was taken as an example. The prepared 1,3-azulenyl polybenzimidazole material (p-PBI-Az-1) 1.0 g was dissolved in 60 mL dimethyl sulfoxide (DMSO) and heated to dissolve at 80 °C, then 1.16 g 1,3-dibromopropane was added, and the reaction was carried out at 80 °C for 4 h; after cooling to room temperature, 20 ml 25 wt% trimethylamine solution was added, and the reaction was carried out for 24 h. The solution after the reaction was poured into water to precipitate, and finally washed with water, filtered, and dried at 80 °C under vacuum for 24 h to obtain the functionalized polymer p-PBI-Az-1-Br, y = 89%.

[0049]

[0050] (3) Preparation and ion exchange of p-PBI-Az-n-OH anion exchange membrane: p-PBI-Az-1-Br (1 g) in step (2) was dissolved in 30 mL DMSO, the polymer solution was filtered through a 0.45 μm polytetrafluoroethylene filter membrane, and the filtrate was cast on a clean glass plate. Subsequently, the solution was evaporated at 80 °C for 12 h, at 120 °C for 12 h, and at 120 °C under vacuum for 24 h to completely remove the residual solvent. The Br - type membrane was peeled off from the glass plate. In 1M KCl solution, ion exchange was carried out at 80 °C for 12 h, then washed with deionized water for 3 times to remove the residual salt, to obtain the Cl - type membrane. In 1M KOH solution, ion exchange was carried out at 80 °C for 12 h, then washed with deionized water for 3 times under nitrogen atmosphere to obtain the OH - type membrane. The thickness of the membrane was 50 μm.

[0051] Example 2

[0052] Preparation of 3,3'-dicarboxyl-1,1'-bi-azulenyl polybenzimidazole (p-PBI-biAz-n) anion exchange membrane:

[0053] (1) Synthesis of 3,3'-dicarboxy-1,1'-bixylyl polybenzimidazole precursor polymer (p-PBI-biAz-n): As an example of the synthesis of p-PBI-biAz-1, 3,3'-diaminobenzidine (2.15 g, 10.03 mmol), terephthalic acid (1.5 g, 9.03 mmol), 3,3'-dicarboxy-1,1'-bixylyl (0.344 g, 0.10 mmol) were charged into a round bottom flask with a stirrer, inert gas inlet and calcium chloride drying tube. Polyphosphoric acid (83.50 g) was added and nitrogen was purged. The resulting mixed solution was stirred at 200 °C for 48 h. After a certain period of reaction, the resulting viscous solution was poured into 200 mL of water to precipitate, and the resulting polymer solid was collected. The solid was neutralized with potassium carbonate solution (300 mL, 1 M), and then washed thoroughly with deionized water, and dried at 80 °C under vacuum for 24 h to obtain black solid p-PBI-biAz-1 (the structure of the polymer was confirmed by nuclear magnetic resonance, infrared; the weight average molecular weight of the polymer was 25.5 kda), y = 87%. Wherein, n = 1 means that the content of 3,3'-dicarboxy-1,1'-bixylyl accounts for 10% of the total dicarboxylic monomer content.

[0054]

[0055] (2) Synthesis of functionalized 3,3'-dicarboxy-1,1'-bixylyl polybenzimidazole p-PBI-biAz-n-Br: As an example of p-PBI-biAz-1-Br, the same as step (2) of Example 1 (process and conditions are the same as step (2) of Example 1), to obtain functionalized polymer p-PBI-biAz-1-Br, y = 85%.

[0056]

[0057] (3) Preparation and ion exchange of p-PBI-biAz-n-OH anion exchange membrane: As an example of p-PBI-biAz-1-OH, the same as step (3) of Example 1 (process and conditions are the same as step (3) of Example 1), to obtain OH - type membrane.

[0058] Example 3

[0059] Preparation of 3,3"-dicarboxy-1,1':3',1"-tertrixylyl polybenzimidazole (p-PBI-triAz-n-OH) anion exchange membrane:

[0060] (1) Synthesis of 3,3"-dicarboxylic acid-1,1 ':3',1 "-terrylenyl polybenzimidazole precursor polymer (p-PBI-triAz-n): As an example of the synthesis of p-PBI-triAz-1, 3,3'-diaminobenzidine (2.15 g, 10.03 mmol), terephthalic acid (1.33 g, 8.03 mmol), [1,1 ':3',1 "-terrylenyl]-3,3"-dicarboxylic acid (0.47 g, 1.00 mmol) were charged into a round bottom flask with a stirrer, inert gas inlet and calcium chloride drying tube. Polyphosphoric acid (83.50 g) was added and purged with nitrogen. The resulting mixed solution was stirred at 200 °C for 48 h. After a certain time of reaction, the resulting viscous solution was poured into 200 mL of water to precipitate, and the resulting polymer solid was collected. The solid was neutralized with potassium carbonate solution (300 mL, 1 M), and then washed thoroughly with deionized water, and dried at 80 °C under vacuum for 24 h to obtain black solid p-PBI-triAz-1 (polymer structure was confirmed by NMR, IR; weight average molecular weight of the polymer was 30.1 kda), y = 81 %. Wherein, n = 1 means that the content of [1,1 ':3',1 "-terrylenyl]-3,3"-dicarboxylic acid accounts for 10% of the total dicarboxylic monomer content.

[0061]

[0062] (2) Synthesis of functionalized 1,1 ',3,3'-tetracarboxy-6,6'-bisterrylene polybenzimidazole (p-PBI-triAz-n-Br): As an example of p-PBI-triAz-1-Br, the same as step (2) of Example 1 (process and conditions are the same as step (2) of Example 1 ), to obtain functionalized polymer p-PBI-triAz-1-Br, y = 93%.

[0063]

[0064] (3) Preparation and ion exchange of p-PBI-triAz-n-OH anion exchange membrane: the same as step (3) in Example 1 (process and conditions are the same as step (3) in Example 1 ), to obtain p-PBI-triAz-1-OH membrane.

[0065] Comparative Example 1

[0066] Preparation of polybenzimidazole anion exchange membrane (p-PBI) with the same preparation method (process and conditions) as Example 1, except that no terrylene carboxylic acid monomer (1,3-terrylenedicarboxylic acid, 3,3'-dicarboxy-1,1 '-bisterrylene, 1,1 ',3,3'-tetracarboxy-6,6'-bisterrylene, etc.) was added in the polymerization step.

[0067] Tests showed that the p-PBI-Az-1 anion exchange membrane prepared in Example 1 exhibited OH- at 80°C. - The conductivity is 121 mS / cm, its anion exchange capacity is 1.81 mmol / g, its swelling ratio is 22%, and it maintains alkaline stability for 500 h at 80 °C in 1 M KOH. The p-PBI-biAz-1 anion exchange membrane prepared in Example 2 maintains alkaline stability for 500 h at 80 °C in 1 M KOH. - The conductivity is 135 mS / cm, its anion exchange capacity is 2.01 mmol / g, its swelling ratio is 23%, and it maintains alkaline stability for 600 h at 80 °C in 1 M KOH. The p-PBI-triAz-1 anion exchange membrane prepared in Example 3 maintains alkaline stability for 600 h at 80 °C in 1 M KOH. - The conductivity is 156 mS / cm, its anion exchange capacity is 2.22 mmol / g, its swelling ratio is 25%, and it maintains alkaline stability for 1000 h at 80 °C and 1 M KOH. In contrast, the polybenzimidazole anion exchange membrane prepared in the comparative example maintains alkaline stability at 80 °C and 1 M KOH. - The conductivity was only 103 mS / cm, its anion exchange capacity was 1.61 mmol / g, and its swelling ratio was 19%. It maintained alkaline stability for 300 h at 80℃ in 1M KOH. The results showed that the anion exchange membrane prepared in the comparative example had significantly lower performance compared to the anion exchange membrane prepared in the examples. Figures 1-3 The graph shows the test results of water absorption, swelling rate, and electrical conductivity for each embodiment and comparative example. Figure 4 The MEA test results for alkaline electrolyzed water in each embodiment and comparative example are shown.

[0068] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An azolyl polybenzimidazole anion exchange membrane, characterized by: The raw material used is an azulene-based polybenzimidazole polymer, the structure of which is shown in formula I: , Formula I In the formula, A represents different types of PBI groups, B is an aromatic group, C is an azulene group, R is a different cationic group, n is a value between 0.01 and 1, and represents the molar ratio of the two groups in the corresponding brackets, with the molar ratio being 1 based on the total number of moles of the two groups in the polymer; A is one or more of the following structures: no A group, i.e. the adjacent phenyl rings are directly connected, , B is one or more of the following structures: , C is one or more of the following structures: , 4 R is one or more of the following structures: , In the group R, n is an integer greater than or equal to 0, and the wavy line "﹏" in the above structure represents the connection.

2. The azulenyipolybenzimidazole anion exchange membrane according to claim 1, characterized by The azulene-based polybenzimidazole polymer of formula I has a weight average molecular weight ranging from 1.0 to 10.0 kda, a film thickness of 10 to 200 μm, and a polymerization mode of the two groups in the corresponding brackets n and (1-n) being random polymerization.

3. The azulene-based polybenzimidazole anion exchange membrane according to claim 1, characterized in that, In the group R of formula I, n is an integer from 0 to 4.

4. The azulene-based polybenzimidazole anion exchange membrane according to claim 1, characterized in that, In the group R of formula I, n is an integer from 5 to 8.

5. A method for preparing the azulene-based polybenzimidazole anion exchange membrane according to any one of claims 1 to 4, the method comprising the following steps: (1) Synthesis of azulene-based polybenzimidazole precursor polymer: The dicarboxy aromatic monomer B-(COOH)2, the dicarboxy azulene monomer C-(COOH)2, 3,3'-diaminobenzidine (DAP) or its derivatives are loaded into a container, an organic solvent α is added, an inert gas is purged, and then a catalyst β is added. The resulting mixed solution is stirred and reacted at 140-220°C, the resulting solution is poured into water to precipitate, and the obtained polymer solid is collected. The solid is neutralized to basic pH>7 with potassium carbonate solution, then washed with water, and dried to obtain azulene-based polybenzimidazole, the structure of which is shown in formula I; The specific structure of the dicarboxy aromatic monomer B-(COOH)2 is the same as that of the corresponding group B structure in claim 1, and is one or more of the corresponding group B structures in claim 1; The specific structure of the dicarboxy azulene monomer C-(COOH)2 is the same as that of the corresponding group C structure in claim 1, and is one or more of the corresponding group C structures in claim 1; The derivative of 3,3'-diaminobenzidine is one or more of 4,4'-oxybis(1,2-phenylenediamine), 4,4'-sulfonylbis(1,2-phenylenediamine), [1,1':3',1''-terphenyl]-3,3'',4,4''-tetramine, and 4,4'-(4-phenylpyridine-2,6-diyl)bis(benzene-1,2-diamine). (2) Synthesis of cationized olybenzimidazole: the olybenzimidazole obtained in step (1) is dissolved in an organic solvent β by heating, a γ reagent with a cationic group is added, and the reaction is stirred by heating at room temperature-120°C in the dark; the obtained solution is precipitated in water, the obtained solid is washed with water and dried to obtain the cationized olybenzimidazole; (3) Preparation of azulene-based polybenzimidazole anion exchange membrane: the cationized azulene-based polybenzimidazole obtained in step (2) is dissolved in an organic solvent, stirred at room temperature and filtered, the filtrate is cast on a flat plate, the solvent is removed, and then the thin film is peeled off from the flat plate to obtain Br - or I - type membrane, the Br - or I - type membrane is placed in a KOH solution for ion exchange to obtain an OH - type membrane, and then washed with water under an inert atmosphere to obtain an azulene-based polybenzimidazole anion exchange membrane.

6. The preparation method according to claim 5, characterized in that, In step (1), the specific structure of the dicarboxylic aromatic monomer B-(COOH)2 is the same as that of the corresponding group B structure in claim 1, and is one or two or more of terephthalic acid, isophthalic acid, 5-methyl isophthalic acid, 2,3,5,6-tetramethyl terephthalic acid, and 5-tert-butyl-1,3-benzenedicarboxylic acid in the corresponding group B structure in claim 1; The specific structure of the dicarboxylic oly monomer C-(COOH)2 is the same as that of the corresponding group C structure in claim 1, and is one or two or more of 1,3-olydicarboxylic acid, 6-methyl oly-1,3-dicarboxylic acid, 6-phenyl oly-1,3-dicarboxylic acid, and [1,1'-bioly]-3,3'-dicarboxylic acid in the corresponding group C structure in claim 1; the solid is neutralized to basic pH = 7-9 with a potassium carbonate solution; In step (2), the temperature for stirring and heating the reaction in the dark is 50-80°C.

7. The preparation method according to claim 5, characterized in that, In step (1), the molar ratio of C-(COOH)2 to B-(COOH)2 is 1:1-99, and the molar ratio of B-(COOH)2+C-(COOH)2 to DAP or its derivative is 1:0.9-1.

2.

8. The preparation method according to claim 7, characterized in that, In step (1), the molar ratio of C-(COOH)2 to B-(COOH)2 is 1:2, and the molar ratio of B-(COOH)2+C-(COOH)2 to DAP or its derivative is 1:1.

05.

9. The preparation method according to claim 5, characterized in that, In step (1), the organic solvent α is selected from at least one or two or more of N,N-dimethylformamide, dimethyl sulfoxide, and polyphosphoric acid; and the mass concentration of B-(COOH)2+C-(COOH)2 in the organic solvent α is 0.01-1 mg / ml.

10. The method of claim 9, wherein, In step (1), the mass concentration of B-(COOH)2+C-(COOH)2 in the organic solvent α is 0.1-0.3 mg / ml.

11. The preparation method according to claim 5, characterized in that, In step (1), the catalyst β is selected from one or two or more of phosphorus pentoxide, polyphosphoric acid, and methanesulfonic acid; and the use amount ratio of the catalyst β to B-(COOH)2+C-(COOH)2 is 1:0.01-100.

12. The method of claim 11, wherein, In step (1), the use amount ratio of the catalyst β to B-(COOH)2+C-(COOH)2 is 1:30-50.

13. The preparation method according to claim 5, characterized in that, In step (2) or (3), the organic solvent β is selected from at least one or two or more of acetonitrile, tetrahydrofuran, N-methyl pyrrolidone, dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, and sulfolane; In step (2), the mass concentration of the azulene-based polybenzimidazole in the organic solvent β is 0.01-100 wt% , The heating dissolution temperature is 20-120℃; the mass ratio of the amount of the γ reagent to the azulene-based polybenzimidazole is 0.1-100:1; the reaction is stirred at room temperature in the dark for 1-100 hours, and the γ reagent is one or two or more of the following structures: ， X is at least one or two of Br or I, and n is an integer greater than or equal to 0.

14. The preparation method according to claim 13, characterized in that, In step (2), the mass concentration of the azulene-based polybenzimidazole in the organic solvent β is 30-50 wt %; The heating dissolution temperature is 60-80℃; the mass ratio of the amount of the γ reagent to the azulene-based polybenzimidazole is 20-50:1; the reaction is stirred at room temperature in the dark for 12-48 hours. In the structure of the γ reagent, n is 0-4.

15. The preparation method according to claim 13, characterized in that, In the structure of the γ reagent, n is 5-8.

16. The method of claim 5, wherein, In step (3), the concentration of the KOH solution is 0.1-5 M.

17. The method of claim 15, wherein, In step (3), the concentration of the KOH solution is 0.5-2 M.

18. An azulene-based polybenzimidazole anion exchange membrane prepared by the preparation method according to any one of claims 5-17.

19. Use of the azulene-based polybenzimidazole anion exchange membrane according to claim 1 or claim 18 as a separator in a fuel cell or an alkaline electrolytic cell.

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