Anion exchange membrane, preparation method, application thereof and electrolysis device

Abstract

The present application relates to the field of electrolysis technology, and provides an anion exchange membrane, a preparation method, an application and an electrolysis device thereof. The anion exchange membrane includes a plurality of polymer main chains and a plurality of crosslinking groups. The plurality of polymer main chains are crosslinked by the plurality of crosslinking groups, and the crosslinking groups contain ether groups. The anion exchange membrane of the present application has high conductivity and good stability.

Description

Technical Field

[0001] The present application relates to the field of electrolysis technology, and particularly to an anion exchange membrane, a preparation method thereof, an application thereof, and an electrolysis device. Background Art

[0002] Hydrogen production by electrolyzing water has become an important way for hydrogen production due to its simple principle and high energy efficiency. Among them, the key to electrolyzing water lies in the electrolyte material used in the electrolytic cell, especially the performance of the membrane material directly affects the electrolysis efficiency and the hydrogen production. The anion exchange membrane (AEM) type electrolytic cell is a new type of electrolytic cell technology that has developed rapidly in recent years, combining the advantages of low cost of traditional alkaline electrolytic cells and high electrolysis efficiency of proton exchange membrane type electrolytic cells. In traditional technologies, quaternary ammonium salt type anion exchange membranes and polyarylpiperidine type anion exchange membranes are used. The quaternary ammonium salt type anion exchange membrane has problems such as poor ion conductivity, insufficient chemical stability, and poor compatibility between the membrane and the electrode interface; the ion conductivity and alkali resistance of the polyarylpiperidine type anion exchange membrane still need to be improved. Therefore, how to improve the conductivity and stability of the anion exchange membrane has become an urgent technical problem to be solved at present. Summary of the Invention

[0003] Based on this, an embodiment of the present application provides an anion exchange membrane with high conductivity and good stability, a preparation method thereof, an application thereof, and an electrolysis device.

[0004] In a first aspect, the present application provides an anion exchange membrane, which includes a plurality of polymer main chains and a plurality of crosslinking groups. The plurality of polymer main chains are crosslinked through the plurality of crosslinking groups, and the crosslinking groups contain ether groups.

[0005] In some embodiments, the crosslinking group includes a crosslinking main chain and a crosslinking side chain grafted on the crosslinking main chain, and the crosslinking main chain and / or the crosslinking side chain contain ether groups.

[0006] In some embodiments, the polymer main chain includes at least one of polyarylpiperidine polymers, polyaryl isatin polymers, and polybenzimidazole polymers.

[0007] In some embodiments, the mass ratio of the polymer main chain to the crosslinking group is 1:(0.06 - 0.5).

[0008] In a second aspect, the present application provides a preparation method of an anion exchange membrane, and the preparation method includes:

[0009] Mixing a solution containing a polymer main chain and a crosslinking agent, crosslinking to form a casting solution, coating the casting solution to obtain a preformed membrane, and the crosslinking agent contains ether groups;

[0010] The prefabricated membrane is subjected to ion exchange treatment to obtain the anion exchange membrane.

[0011] In some embodiments, the mass ratio of the crosslinking agent to the polymer backbone is (0.06~0.5):1.

[0012] In some embodiments, the mass concentration of the polymer backbone in the solution containing the polymer backbone is 5%~25%.

[0013] In some embodiments, the crosslinking agent includes a polyhaloether-based compound; optionally, the crosslinking agent includes at least one of 1,2-bis(2-chloroethoxy)ethane, 1,2-bis(2-bromoethoxy)ethane, 1,2-bis(2-iodoethoxy)ethane, 1,2-dichloro-1-ethoxyethane, 1,2-bis(4-chlorophenoxy)ethane, 1,2-bis(chloroacetoxy)ethane, and 1,6-dibromo-2,5-dioxaperfluorohexane.

[0014] In some embodiments, the ion exchange treatment includes:

[0015] Performing a first ion exchange treatment on the prefabricated membrane with a metal salt solution;

[0016] Performing a second ion exchange treatment on the prefabricated membrane with an alkali solution.

[0017] Optionally, the metal salt contained in the metal salt solution includes at least one of NaBr, NaCl, and KBr.

[0018] Optionally, the basic compound contained in the alkali solution includes at least one of potassium hydroxide, sodium hydroxide, and calcium hydroxide.

[0019] In some embodiments, the preparation method of the polymer backbone includes:

[0020] Mixing an aromatic monomer and a ketone monomer to obtain a first solution;

[0021] Mixing the first solution and an acidic catalyst to obtain a polymer backbone intermediate;

[0022] Mixing the polymer backbone intermediate, an acid-binding agent, and a haloalkane to obtain a second solution, and performing quaternization to obtain the polymer backbone.

[0023] In some embodiments, the molar ratio of the aromatic monomer to the ketone monomer is 1~1.2:1.

[0024] In some embodiments, the mass ratio of the haloalkane to the polymer backbone intermediate is (0.2~0.8):1.

[0025] In some embodiments, the mass ratio of the acid-binding agent to the polymer main chain intermediate is (0.3 to 0.8):1.

[0026] In some embodiments, the aromatic monomer includes at least one of p-terphenyl, m-terphenyl, biphenyl, benzylbenzene, and 9,9'-diphenylfluorene.

[0027] In some embodiments, the ketone monomer includes at least one of N-methyl-4-piperidone, isatin, 3-quinuclidone, 1,1,1-trifluoroacetone, and 2,2,2-trifluoroacetophenone.

[0028] In some embodiments, the haloalkane includes at least one of methyl iodide, ethyl iodide, and 2-iodopropane.

[0029] In some embodiments, the acid-binding agent includes at least one of potassium carbonate, sodium hydride, sodium bicarbonate, trimethylamine, and sodium carbonate.

[0030] In some embodiments, the acidic catalyst includes at least one of trifluoroacetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, perfluoropropionic acid, pentafluoroethanesulfonic acid, and heptafluorobutyric acid.

[0031] Optionally, the acidic catalyst includes trifluoroacetic acid and trifluoromethanesulfonic acid. Further optionally, the molar ratio of trifluoroacetic acid to the ketone monomer is 1 to 1.5:1; the molar ratio of trifluoromethanesulfonic acid to the ketone monomer is 9 to 12:1.

[0032] In a third aspect, the present application provides an application of the anion exchange membrane as described in the first aspect in the preparation of an electrolysis device.

[0033] In a fourth aspect, the present application provides an electrolysis device, which includes the anion exchange membrane as described in the first aspect and / or an anion exchange membrane prepared by the preparation method of the anion exchange membrane as described in the second aspect.

[0034] Compared with the traditional technology, the present application has at least the following beneficial effects:

[0035] The present application crosslinks the polymer main chain with a crosslinking group containing an ether group. The ether group in the crosslinking group can effectively induce the self-aggregation of ionic groups, thereby forming a developed ion transport channel and effectively improving the conductivity. Moreover, introducing a crosslinking group into the anion exchange membrane can effectively improve its anti-swelling performance, and further improve the dimensional stability of the anion exchange membrane. Description of the Drawings

[0036] Figure 1FT-IR spectra of the polymer main chains prepared in Example 3 and Comparative Example 1 of this application;

[0037] Figure 2 Mechanical strength diagrams of the anion exchange membranes prepared in Example 3 and Comparative Example 1 of this application;

[0038] Figure 3 Polarization curves of alkaline electrolyzed water in the electrolysis devices in Example 3 and Comparative Example 1 of this application;

[0039] Figure 4 Microscopic morphology comparison diagrams of Example 3 and Comparative Example 1 of this application. Detailed implementation manners

[0040] The following combines the implementation manners and examples to further elaborate on this application in detail. These implementation manners and examples are only used to illustrate this application and not to limit the scope of this application. The purpose of providing these implementation manners and examples is to make the understanding of the disclosed content of this application more thorough and comprehensive. It should also be understood that this application can be implemented in many different forms and is not limited to the implementation manners and examples described herein. Those skilled in the art can make various changes or modifications without departing from the connotation of this application, and the equivalent forms obtained also fall within the protection scope of this application. In addition, in the following description, a large number of specific details are given to provide a more thorough understanding of this application. It should be understood that this application can be implemented without one or more of these details.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] In this application, "optionally", "optional", "option" mean optional, that is, it refers to any one of the two parallel options of "yes" or "no". If the term "optional" appears multiple times in a technical solution, without special instructions and without contradictions or mutual constraints, each "optional" is independent of each other.

[0043] In "the first aspect", "the second aspect", etc. of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0044] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, as well as an open technical solution containing the listed features.

[0045] In this application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values within this numerical interval is considered continuous, and it includes the two numerical endpoints of this numerical interval (i.e., the minimum value and the maximum value), as well as each numerical value between these two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within this numerical interval, it includes the two endpoint integers of this numerical range, as well as each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all sub-ranges subsumed therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" allows for a broad inclusion of quantitative intervals such as a percentage interval, a ratio interval, a ratio value interval, etc.

[0046] All the documents mentioned in this application are cited as references in this application, just as if each document was cited separately as a reference. Unless it conflicts with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited in their entirety and for all purposes. When this application involves cited documents, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited together. When this application involves cited documents, the examples and preferred methods of the relevant technical features cited can also be incorporated as references into this application, but only to the extent that this application can be implemented. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or be amended adaptively according to the description of this application.

[0047] In traditional technologies, a crosslinked anion exchange membrane is prepared by introducing a hydrophobic crosslinking agent into the polymer backbone. Although the hydrophobic crosslinked structure can effectively inhibit the water absorption and swelling of the anion exchange membrane, enhance the dimensional stability of the membrane, and improve the mechanical properties of the membrane. However, the introduction of the hydrophobic crosslinked structure will also sacrifice the ion exchange ability of the anion exchange membrane, and there are problems such as unclear microphase separation and low ion conductivity.

[0048] In the first aspect of this application, an anion exchange membrane is provided. The anion exchange membrane includes a plurality of polymer backbones and a plurality of crosslinking groups. The plurality of polymer backbones are crosslinked through the plurality of crosslinking groups, and the crosslinking groups contain ether groups.

[0049] In this application, a cross-linking group containing an ether group is used to cross-link the polymer main chain. The ether group in the cross-linking group can effectively induce the self-aggregation of ionic groups, thereby forming a well-developed ion transport channel and effectively improving the conductivity. Moreover, introducing a cross-linking group into the anion exchange membrane can improve the anti-swelling performance and further improve the dimensional stability of the anion exchange membrane.

[0050] In some embodiments, the cross-linking group includes a cross-linking main chain containing an ether group.

[0051] In some embodiments, the cross-linking group includes a cross-linking main chain and cross-linking branches grafted onto the cross-linking main chain. For example, the cross-linking branches can be alkyl groups. Optionally, the cross-linking main chain can contain an ether group; or the cross-linking branches can also contain an ether group; or both the cross-linking main chain and the cross-linking branches contain an ether group.

[0052] It can be understood that the cross-linking main chain can be composed of alkyl groups, and the cross-linking branches can also be composed of alkyl groups.

[0053] In some embodiments, the polymer main chain includes at least one of polyarylpiperidine polymers, polyaryl isatin polymers, and polybenzimidazole polymers. Optionally, the polymer main chain includes a quaternized polyarylpiperidine polymer. In this application, a quaternized polyarylpiperidine polymer is used as the polymer main chain, which cooperates with the cross-linking group containing an ether group, has good microphase separation and good anti-swelling properties, and can improve the ionic conductivity and dimensional stability of the anion exchange membrane.

[0054] It can be understood that other modifying groups can also be grafted onto the polymer main chain in this application to modify the polymer main chain, thereby improving the performance of the anion exchange membrane. For example, part of the polymer main chain is iodomethanated.

[0055] In some embodiments, the mass ratio of the polymer main chain to the cross-linking group is 1:(0.06 - 0.5), for example, it can be 1:0.06, 1:0.10, 1:0.15, 1:0.20, 1:0.25, 1:0.30, 1:0.35, 1:0.40, 1:0.45, or 1:0.50. By selecting the above mass ratio of the polymer main chain and the cross-linking group in this application, problems such as the casting solution gel not being able to be cast into a film and the inability to successfully cross-link are avoided, effectively ensuring the stability and conductivity of the anion exchange membrane.

[0056] In the second aspect of this application, a preparation method of an anion exchange membrane is provided, and the preparation method includes:

[0057] Mix a solution containing a polymer main chain with a cross-linking agent, and after cross-linking, a casting solution is formed. The casting solution is coated to obtain a preformed membrane, and the cross-linking agent contains an ether group;

[0058] The prefabricated membrane is subjected to ion exchange treatment to prepare the anion exchange membrane.

[0059] In the present application, the anion exchange membrane is prepared as above. A crosslinking agent containing an ether group is used to carry out a crosslinking reaction on the polymer main chain. The ether group in the crosslinking agent can effectively induce the self-aggregation of ionic groups, thereby forming a developed ion transport channel and effectively improving the conductivity. Moreover, introducing crosslinking groups into the anion exchange membrane can improve the anti-swelling performance and further improve the dimensional stability of the anion exchange membrane.

[0060] In some embodiments, the mass ratio of the crosslinking agent to the polymer main chain is (0.06~0.5):1.

[0061] In some embodiments, the mass concentration of the polymer main chain in the solution containing the polymer main chain is 5%~25%, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24% or 25%.

[0062] In some embodiments, the crosslinking agent includes a polyhaloether-based compound. For example, the crosslinking agent can be a dihaloalkane containing an ether group.

[0063] Optionally, the crosslinking agent includes at least one of 1,2-bis(2-chloroethoxy)ethane, 1,2-bis(2-bromoethoxy)ethane, 1,2-bis(2-iodoethoxy)ethane, 1,2-dichloro-1-ethoxyethane, 1,2-bis(4-chlorophenoxy)ethane, 1,2-bis(chloroacetoxy)ethane, and 1,6-dibromo-2,5-dioxaperfluorohexane.

[0064] In some embodiments, the solvent in the casting solution includes at least one of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0065] In some embodiments, after the casting solution is coated and formed into a film, it is subjected to a drying treatment to prepare the prefabricated membrane. Optionally, the temperature of the drying treatment is 60°C~100°C, and the time is 24h~36h.

[0066] In some embodiments, the ion exchange treatment includes:

[0067] The prefabricated membrane is subjected to a first ion exchange treatment with a metal salt solution;

[0068] The prefabricated membrane is subjected to a second ion exchange treatment with an alkali solution.

[0069] In the present application, the ion exchange treatment is carried out as above. Compared with the ion exchange treatment using only an alkali solution, the ion exchange is fast and thorough.

[0070] Optionally, the metal salts contained in the metal salt solution include at least one of NaBr, NaCl, and KBr. Optionally, the molar concentration of the metal salt is 0.2 mol / L to 1 mol / L.

[0071] Optionally, the basic compounds contained in the base solution include at least one of potassium hydroxide, sodium hydroxide, and calcium hydroxide. Optionally, the molar concentration of the basic compound is 0.5 mol / L to 2 mol / L.

[0072] In some embodiments, the method for preparing the polymer backbone includes:

[0073] Mixing an aromatic monomer and a ketone monomer to obtain a first solution;

[0074] Mixing the first solution and an acidic catalyst to prepare an intermediate of the polymer backbone;

[0075] Mixing the intermediate of the polymer backbone, an acid-binding agent, and a haloalkane to obtain a second solution, and subjecting it to quaternization to obtain the polymer backbone.

[0076] In some embodiments, after mixing the first solution and the acidic catalyst, a first precipitating agent is added to precipitate the intermediate of the polymer backbone. Optionally, the intermediate of the polymer backbone is also washed and dried under vacuum.

[0077] Optionally, the first precipitating agent includes at least one of anhydrous methanol, anhydrous ethanol, potassium hydroxide solution, sodium hydroxide solution, potassium carbonate solution, sodium carbonate solution, and sodium bicarbonate solution.

[0078] Optionally, the temperature for vacuum drying is 30°C to 100°C, and the time is 24 h to 36 h.

[0079] In some embodiments, the molar ratio of the aromatic monomer to the ketone monomer is 1 to 1.2:1, for example, it can be 1.05:1, 1.10:1, 1.15:1, or 1.20:1.

[0080] In some embodiments, the mass ratio of the haloalkane to the intermediate of the polymer backbone is (0.2 to 0.8):1, for example, it can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, or 0.8:1.

[0081] In some embodiments, the mass ratio of the acid-binding agent to the intermediate of the polymer backbone is (0.3 to 0.8):1, for example, it can be 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, or 0.8:1.

[0082] In some embodiments, the temperature for quaternization is 30°C to 40°C, the environment is light - protected, and the time is 24h to 48h.

[0083] In some embodiments, a second precipitating agent is added to the quaternized solution. After precipitation, the precipitate is washed and dried to obtain the polymer backbone. Optionally, the second precipitating agent includes at least one of ethyl acetate, acetone, and diethyl ether.

[0084] In some embodiments, the aromatic monomer includes at least one of p - terphenyl, m - terphenyl, biphenyl, bibenzyl, and 9,9'-diphenylfluorene.

[0085] In some embodiments, the ketone monomer includes at least one of N - methyl - 4 - piperidone, isatin, 3 - quinuclidinone, 1,1,1 - trifluoroacetone, and 2,2,2 - trifluoroacetophenone.

[0086] In some embodiments, the haloalkane includes at least one of methyl iodide, ethyl iodide, and 2 - iodopropane.

[0087] In some embodiments, the acid - binding agent includes at least one of potassium carbonate, sodium hydride, sodium bicarbonate, trimethylamine, and sodium carbonate.

[0088] In some embodiments, the acidic catalyst includes at least one of trifluoroacetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, perfluoropropionic acid, pentafluoroethanesulfonic acid, and heptafluorobutyric acid.

[0089] Optionally, the acidic catalyst includes trifluoroacetic acid and trifluoromethanesulfonic acid.

[0090] Further optionally, the molar ratio of the trifluoroacetic acid to the ketone monomer is 1 to 1.5:1; the molar ratio of the trifluoromethanesulfonic acid to the ketone monomer is 9 to 12:1.

[0091] In some embodiments, the solvent contained in the first solution includes at least one of dichloromethane, trifluoroacetic acid, and trifluoromethanesulfonic acid.

[0092] In some embodiments, the solvent contained in the second solution includes at least one of dimethyl sulfoxide, N - methylpyrrolidone, N,N - dimethylformamide, and N,N - dimethylacetamide.

[0093] Exemplarily, a method for preparing the above - mentioned anion - exchange membrane is provided, including the following steps:

[0094] (1) Polymer backbone

[0095] Mix the aromatic monomer and the ketone monomer in a molar ratio of 1 to 1.2:1 to obtain a first solution; add an acidic catalyst to the first solution, react for 6 to 8 hours, then add a precipitant, wash the precipitate until neutral, and then vacuum dry it at 30°C to 100°C for 24 to 36 hours to obtain a polymer main chain intermediate;

[0096] Dissolve the polymer main chain intermediate, then add a deacidifying agent and a haloalkane, carry out a quaternization reaction in the dark at 30°C to 40°C for 24 to 48 hours, then add a second precipitant, wash the precipitate with deionized water multiple times, and then vacuum dry it at 60°C to 100°C for 24 to 36 hours to obtain a polymer main chain;

[0097] (2)Precast film

[0098] Dissolve the polymer main chain to form a solution with a mass concentration of 5% to 25%, add a crosslinking agent to the solution containing the polymer main chain to obtain a casting solution, the mass ratio of the crosslinking agent to the polymer main chain is (0.06 to 0.5):1, coat the casting solution into a film, the crosslinking agent contains an ether group, and dry it at 60°C to 100°C for 24 to 36 hours to obtain a precast film;

[0099] (3)Ion treatment

[0100] First, perform a first ion exchange treatment on the precast film with a metal salt solution; then perform a second ion exchange treatment on the precast film with an alkali solution to prepare the anion exchange membrane.

[0101] The third aspect of the present application provides an application of the anion exchange membrane as described in the first aspect in the preparation of an electrolysis device.

[0102] The fourth aspect of the present application provides an electrolysis device, which includes the anion exchange membrane as described in the first aspect and / or the anion exchange membrane prepared by the preparation method of the anion exchange membrane as described in the second aspect.

[0103] In some embodiments, the electrolysis device includes a cathode, an anode, an anion exchange membrane, and an electrolytic cell filled with an electrolyte solution. The cathode, the anode, and the anion exchange membrane are respectively arranged in the electrolytic cell, and the anion exchange membrane is arranged between the cathode and the anode.

[0104] The following will describe the implementation schemes of the present application in detail with reference to embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. For the experimental methods without specific conditions in the following embodiments, first refer to the guidance given in the present application, and it is also possible to follow the experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to the experimental methods known in the art.

[0105] Example 1

[0106] (1) Polymer main chain

[0107] Under ice bath conditions, 4.6 g of p-terphenyl and 2.5 mL of N-methyl-4-piperidone were added to 10 mL of dichloromethane and mixed to obtain a first solution; a mixed solution containing 1.5 mL of trifluoroacetic acid and 16 mL of trifluoromethanesulfonic acid was added to the first solution. After reacting for 6 h, anhydrous methanol was added for precipitation. After the precipitate was washed to neutrality, it was vacuum dried at 60 °C for 24 h to obtain a polymer main chain intermediate;

[0108] 1 g of the above polymer main chain intermediate was dissolved in 10 mL of NMP and 10 mL of DMSO, then 0.5 g of potassium carbonate and 0.34 mL of iodomethane were added, and a quaternization reaction was carried out under dark conditions at 30 °C for 24 h. Then it was mixed with ethyl acetate for precipitation. After the precipitate was washed with deionized water multiple times, it was vacuum dried at 60 °C for 24 h to obtain the polymer main chain;

[0109] (2) Preformed film

[0110] 0.5 g of the polymer main chain prepared in step (1) was dissolved in 10 mL of DMSO, 0.04 mL of 1,2-bis(2-chloroethoxy)ethane was added to the solution containing the polymer main chain and stirred for 24 h to obtain a casting solution. The casting solution was coated on a glass plate and dried at 90 °C for 24 h to obtain a preformed film;

[0111] (3) Ion treatment

[0112] The preformed film was subjected to a first ion exchange treatment with a 0.5 mol / L NaBr solution; then the preformed film was subjected to a second ion exchange treatment with a 1 mol / L KOH solution to prepare the anion exchange membrane.

[0113] Example 2

[0114] (1) Polymer main chain

[0115] Under ice bath conditions, 4.6 g of p-terphenyl and 2.5 mL of N-methyl-4-piperidone were added to 10 mL of dichloromethane and mixed to obtain a first solution; a mixed solution containing 1.8 mL of trifluoroacetic acid and 18 mL of trifluoromethanesulfonic acid was added to the first solution. After reacting for 7 h, anhydrous methanol was added for precipitation. After the precipitate was washed to neutrality, it was vacuum dried at 70 °C for 36 h to obtain a polymer main chain intermediate;

[0116] Dissolve 1 g of the above polymer main chain intermediate in 10 mL of NMP and 10 mL of DMSO, then add 0.5 g of potassium carbonate and 0.3 mL of methyl iodide, and carry out the quaternization reaction at 35 °C in the dark for 36 h. Then mix it with ethyl acetate for precipitation. After washing the precipitate with deionized water multiple times, dry it in vacuo at 60 °C for 24 h to obtain the polymer main chain;

[0117] (2)Precast film

[0118] Dissolve 0.5 g of the polymer main chain prepared in step (1) in 10 mL of DMSO, add 0.08 mL of 1,2-bis(2-chloroethoxy)ethane to the solution containing the polymer main chain, stir for 24 h to obtain a casting solution, coat the casting solution on a glass plate, and dry it at 120 °C for 24 h to obtain a precast film;

[0119] (3)Ion treatment

[0120] Carry out the first ion exchange treatment on the precast film with a NaBr solution with a molar concentration of 0.5 mol / L; then carry out the second ion exchange treatment on the precast film with a KOH solution with a molar concentration of 1 mol / L to prepare the anion exchange membrane.

[0121] Example 3

[0122] (1)Polymer main chain

[0123] Under ice bath conditions, add 4.6 g of p-terphenyl and 2.1 mL of N-methyl-4-piperidone to 10 mL of dichloromethane and mix to obtain a first solution; add a mixed solution containing 2 mL of trifluoroacetic acid and 20 mL of trifluoromethanesulfonic acid to the first solution. After reacting for 8 h, add anhydrous methanol for precipitation. After washing the precipitate to neutrality, dry it in vacuo at 100 °C for 36 h to obtain a polymer main chain intermediate;

[0124] Dissolve 1 g of the above polymer main chain intermediate in 10 mL of NMP and 10 mL of DMSO, then add 0.6 g of potassium carbonate and 0.19 mL of methyl iodide, and carry out the quaternization reaction at 40 °C in the dark for 48 h. Then mix it with ethyl acetate for precipitation. After washing the precipitate with deionized water multiple times, dry it in vacuo at 80 °C for 30 h to obtain the polymer main chain, and the FT-IR spectrum is as Figure 1 shown;

[0125] (2)Precast film

[0126] Dissolve 0.5 g of the polymer backbone prepared in step (1) in 10 mL of DMSO. Add 0.2 mL of 1,2-bis(2-chloroethoxy)ethane to the solution containing the polymer backbone and stir for 24 h to obtain a casting solution. Coat the casting solution on a glass plate and dry it at 150 °C for 36 h to obtain a prefabricated film;

[0127] (3) Ion treatment

[0128] Perform the first ion exchange treatment on the prefabricated film with a NaBr solution having a molar concentration of 0.5 mol / L; then perform the second ion exchange treatment on the prefabricated film with a KOH solution having a molar concentration of 1 mol / L to prepare the anion exchange membrane.

[0129] Example 4

[0130] Prepare the anion exchange membrane according to the method of Example 3, except that the added volume of the crosslinking agent 1,2-bis(2-chloroethoxy)ethane is 0.02 mL.

[0131] Example 5

[0132] Prepare the anion exchange membrane according to the method of Example 3, except that the added volume of the crosslinking agent 1,2-bis(2-chloroethoxy)ethane is 0.3 mL.

[0133] Comparative Example 1

[0134] (1) Polymer backbone

[0135] Under ice bath conditions, add 4.6 g of p-terphenyl and 2.3 mL of N-methyl-4-piperidone to 10 mL of dichloromethane and mix to obtain a first solution; add a mixed solution containing 1.6 mL of trifluoroacetic acid and 16 mL of trifluoromethanesulfonic acid to the first solution. After reacting for 7.5 h, add anhydrous methanol for precipitation. Wash the precipitate until neutral, and then dry it under vacuum at 90 °C for 30 h to obtain a polymer backbone intermediate;

[0136] Dissolve 1 g of the above polymer backbone intermediate in 10 mL of NMP and 10 mL of DMSO, then add 0.6 g of potassium carbonate and 0.6 mL of iodomethane, and carry out a quaternization reaction in the dark at 40 °C for 48 h. Then mix it with diethyl ether for precipitation. Wash the precipitate with deionized water multiple times, and then dry it under vacuum at 100 °C for 36 h to obtain the polymer backbone. The FT-IR spectrum is as Figure 1 shown;

[0137] (2) Prefabricated film

[0138] Dissolve 0.5 g of the polymer backbone prepared in step (1) in 10 mL of DMSO, centrifuge to remove impurities to obtain a casting solution, coat the casting solution on a glass plate, and dry it at 100 °C for 30 h to obtain a prefabricated membrane;

[0139] (3)Ion treatment

[0140] Perform the first ion exchange treatment on the prefabricated membrane with a NaBr solution having a molar concentration of 0.5 mol / L; then perform the second ion exchange treatment on the prefabricated membrane with a KOH solution having a molar concentration of 1 mol / L to prepare the anion exchange membrane.

[0141] Comparative Example 2

[0142] Prepare the anion exchange membrane according to the method of Example 3, except that in step (2), the crosslinking agent 1,2-bis(2-chloroethoxy)ethane is replaced with 0.19 mL of dibromohexane.

[0143] Perform performance testing on the anion exchange membranes prepared in the above examples and comparative examples. The testing methods include:

[0144] Impedance testing: Detect the impedance of the anion exchange membrane by the p-EIS method using an electrochemical workstation (gamry) at room temperature (25 °C);

[0145] Conductivity: Measure the resistance value at room temperature (25 °C) by the p-EIS impedance method, and calculate the conductivity of the membrane through the formula σ = L / RA, (where R is the impedance value of the membrane, L is the thickness of the membrane, and A is the effective area of the membrane);

[0146] Tensile strength and elongation at break: Detect the tensile strength and elongation at break of the wet membrane using a tensile machine (LABRD-V2.9), Figure 2 Figure for comparing the mechanical strengths of the anion exchange membranes in Example 3 and Comparative Example 1;

[0147] Sol-gel fraction: Place a certain mass of the dry membrane in a DMSO solution at 80 °C for 2 days, then take out the membrane and wash the surface solvent with deionized water, place it in a vacuum oven at 60 °C and dry it to a constant weight, record its dry membrane mass, and detect the sol-gel fraction through the formula GF = Wa / Wb×100% (where Wb represents the dry membrane mass before testing, and Wa represents the remaining dry membrane mass after dissolving in DMSO);

[0148] Alkali absorption rate: A membrane of a certain size was immersed in 1M KOH at room temperature for 24h. Then the membrane was taken out, wiped with absorbent paper to remove the liquid on the surface, and weighed. Then the membrane sample was wrapped regularly with absorbent paper and dried in vacuum at 60℃ for 24 hours. Then its dry weight was weighed. The alkali absorption rate was detected using the formula W=(Wwet-Wdry) / Wdry × 100% (where Wwet represents the mass of the wet membrane and Wdry represents the mass of the dry membrane).

[0149] Microstructural characterization: The microstructure of the anion exchange membrane was measured using a transmission electron microscope (JEOL JEM-2000EX). Figure 4 Figure 5 is a comparative micrograph of the anion exchange membranes in Example 3 and Comparative Example 1.

[0150] The test results are shown in Table 1.

[0151] Table 1

[0152]

[0153] The anion exchange membranes prepared in the above examples and comparative examples were assembled into an electrolysis device. The electrolyte in the electrolysis device was 1mol / L KOH solution. The cathode used 2.3mm compressed nickel foam, 0.6mm raw carbon cloth and 0.3mm catalyst carbon cloth, and the anode used 2.5mm compressed catalyst nickel foam.

[0154] The current density of the above electrolysis device was tested at 55℃ and 2V voltage. The polarization curves of water electrolysis in Example 3 and Comparative Example 1 are as Figure 3 shown, and the test results are shown in Table 2.

[0155] Table 2

[0156]

[0157] It can be seen from the above table that

[0158] (1) Comparing Example 3 with Examples 4-5, it can be seen that by adjusting the mass ratio of the crosslinking agent to the polymer main chain in this application, good microphase separation, relatively high ion conductivity and good electrolysis performance are obtained.

[0159] (2) Comparing Example 3 with Comparative Examples 1-2, in this application, a crosslinking agent containing an ether group is used for crosslinking, which improves the mechanical properties of the anion exchange membrane, has good stability, and promotes microphase separation in the membrane. Its conductivity has been significantly improved, and the high ion conductivity makes the battery performance improved.

[0160] In this application, the polymer backbone is first prepared through Friedel-Crafts alkylation reaction; after the quaternization of the polymer backbone is achieved by using the Menxiu Jin reaction, a crosslinking reaction is carried out; finally, the anion exchange membrane can be prepared by the casting method and alkalized to obtain polymer membranes with different crosslinking degrees. The introduction of a crosslinking group containing an ether group not only improves the dimensional stability and mechanical properties of the membrane, but also improves the microphase separation structure in the membrane, promoting the improvement of the ion conductivity. The anion membrane prepared in this application exhibits excellent alkali stability, high ion conductivity and excellent mechanical strength.

[0161] In summary, this application uses a crosslinking group containing an ether group to crosslink the polymer backbone. The ether group in the crosslinking group can effectively induce the self-aggregation of ionic groups, thereby forming a well-developed ion transport channel and effectively improving the conductivity. Moreover, the introduction of a crosslinking group in the anion exchange membrane can improve the anti-swelling performance, and further improve the dimensional stability of the anion exchange membrane.

[0162] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0163] The above-described embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application should be subject to the appended claims.

Claims

1. An anion exchange membrane, characterized in that The anion exchange membrane comprises a plurality of polymer main chains and a plurality of cross-linking groups, the plurality of polymer main chains are cross-linked by a plurality of the cross-linking groups, and the cross-linking groups contain ether groups; The anion exchange membrane is prepared by the following preparation method: A solution containing a polymer main chain and a cross-linking agent are mixed to form a casting solution after cross-linking, and the casting solution is coated to obtain a prefabricated membrane, so that a plurality of the polymer main chains are cross-linked through a plurality of the cross-linking groups, and the cross-linking agent contains an ether group; The prefabricated membrane is subjected to ion exchange treatment to prepare the anion exchange membrane; The mass ratio of the crosslinking agent to the polymer main chain is (0.06-0.5):1, the crosslinking agent includes a polyhalogenated ether compound, and the crosslinking agent includes at least one of 1,2-bis(2-chloroethoxy)ethane, 1,2-bis(2-bromoethoxy)ethane, 1,2-bis(2-iodoethoxy)ethane, 1,2-dichloro-1-ethoxyethane, 1,2-bis(4-chlorophenoxy)ethane, 1,2-bis(chloroacetoxy)ethane and 1,6-dibromo-2,5-dioxoperfluorohexane.

2. The anion exchange membrane according to claim 1, characterized in that The anion exchange membrane satisfies at least one of the following conditions: (1) The polymer main chain comprises at least one of a polyarylpiperidine polymer, a polyarylisatin polymer and a polybenzimidazole polymer; (2) The mass ratio of the polymer main chain to the cross-linking group is 1:(0.06-0.5).

3. A method for preparing an anion exchange membrane, characterized in that: The preparation method comprises: A solution containing a polymer main chain and a cross-linking agent are mixed to form a casting solution after cross-linking, and the casting solution is coated to obtain a prefabricated membrane, wherein the cross-linking agent contains an ether group, so that a plurality of the polymer main chains are cross-linked through a plurality of cross-linking groups, and the cross-linking groups contain an ether group; The prefabricated membrane is subjected to ion exchange treatment to prepare the anion exchange membrane; The mass ratio of the crosslinking agent to the polymer main chain is (0.06-0.5):1, the crosslinking agent includes a polyhalogenated ether compound, and the crosslinking agent includes at least one of 1,2-bis(2-chloroethoxy)ethane, 1,2-bis(2-bromoethoxy)ethane, 1,2-bis(2-iodoethoxy)ethane, 1,2-dichloro-1-ethoxyethane, 1,2-bis(4-chlorophenoxy)ethane, 1,2-bis(chloroacetoxy)ethane and 1,6-dibromo-2,5-dioxoperfluorohexane.

4. The method for preparing an anion exchange membrane according to claim 3, characterized in that: The mass concentration of the polymer main chain in the solution containing the polymer main chain is 5% to 25%.

5. The method for preparing an anion exchange membrane according to claim 4, characterized in that: The ion exchange treatment comprises: Performing a first ion exchange treatment on the prefabricated membrane using a metal salt solution; The prefabricated membrane is subjected to a second ion exchange treatment using an alkaline solution.

6. The method for preparing an anion exchange membrane according to claim 5, characterized in that: The metal salt contained in the metal salt solution includes at least one of NaBr, NaCl and KBr.

7. The method for preparing an anion exchange membrane according to claim 5, characterized in that: The alkaline compound contained in the alkaline solution includes at least one of potassium hydroxide, sodium hydroxide and calcium hydroxide.

8. The method for preparing an anion exchange membrane according to any one of claims 3 to 7, characterized in that: The preparation method of the polymer main chain comprises: mixing an aromatic monomer and a ketone monomer to obtain a first solution; Mixing the first solution and an acidic catalyst to prepare a polymer main chain intermediate; The polymer main chain intermediate, the acid binding agent and the halogenated alkane are mixed and quaternized to obtain the polymer main chain.

9. The method for preparing an anion exchange membrane according to claim 8, characterized in that: (1) The molar ratio of the aromatic monomer to the ketone monomer is 1 to 1.2:1; (2) The mass ratio of the halogenated alkane to the polymer main chain intermediate is (0.2-0.8):1; (3) The mass ratio of the acid binding agent to the polymer main chain intermediate is (0.3-0.8):1; (4) the aromatic monomer comprises at least one of p-terphenyl, m-terphenyl, biphenyl, bibenzyl and 9,9'-diphenylfluorene; (5) the ketone monomer comprises at least one of N-methyl-4-piperidone, isatin, 3-quininone, 1,1,1-trifluoroacetone and 2,2,2-trifluoroacetophenone; (6) The halogenated alkane comprises at least one of methyl iodide, ethyl iodide and 2-iodopropane; (7) The acid binding agent comprises at least one of potassium carbonate, sodium hydride, sodium bicarbonate, trimethylamine and sodium carbonate; (8) The acidic catalyst includes at least one of trifluoroacetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, perfluoropropionic acid, pentafluoroethanesulfonic acid and heptafluorobutyric acid.

10. The method for preparing an anion exchange membrane according to claim 9, characterized in that: The acidic catalysts include trifluoroacetic acid and trifluoromethanesulfonic acid.

11. The method for preparing an anion exchange membrane according to claim 10, characterized in that: The molar ratio of the trifluoroacetic acid to the ketone monomer is 1 to 1.5:1; the molar ratio of the trifluoromethanesulfonic acid to the ketone monomer is 9 to 12:

1.

12. Use of the anion exchange membrane according to claim 1 or 2 in preparing an electrolysis device.

13. An electrolysis device, characterized in that: The electrolysis device comprises the anion exchange membrane according to claim 1 or 2 and / or an anion exchange membrane prepared by the method for preparing an anion exchange membrane according to any one of claims 3-11.

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