Anion exchange polymers containing zwitterionic side chain structures and their applications

Abstract

The present invention provides an anion exchange polymer containing a zwitterionic side chain structure and its application, the polymer includes a sulfonate group with a negative charge, an ammonium salt with a positive charge and a carbon chain connecting the ammonium salt and the sulfonate group, and obtains one or more combinations of quaternary ammonium salt-sulfonate zwitterions, imidazolammonium salt-sulfonate zwitterions, cyclic piperidinium salt-sulfonates, quinuclidine ammonium salt-sulfonates represented by cyclic quaternary ammonium salt-sulfonate zwitterions, pyridinium salt-sulfonate zwitterions, and quinuclidine ammonium salt-sulfonate zwitterions. First, the zwitterionic side chain structure embodies good chemical stability, and the anion exchange membrane containing the zwitterionic side chain structure can be adjusted by adjusting the content of its zwitterions, so that hydroxide is accelerated to pass along the direction of the electric field under the electrostatic repulsion, thereby improving ionic conductivity, and at the same time, due to the electrostatic action of the sulfonate and ammonium salts between the molecular chains, the mechanical properties of the anion exchange membrane are improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy electrochemical devices, and in particular to an anion exchange polymer containing a zwitterionic side chain structure and applications thereof. Background Art

[0002] Anion exchange membranes and anion exchange polymer adhesives are a class of high molecular polymers that contain cationic functional groups and have selective permeability to anions. However, current application scenarios require anion exchange membranes to have higher conductivity, better mechanical, thermal and chemical stability. In recent years, with the growing demand for alternative energy worldwide, the application of anion exchange membranes and anion exchange polymer adhesives in new energy electrochemical devices has also attracted the attention of more and more researchers. They can be used in alkaline fuel cells, water electrolysis, carbon dioxide reduction, flow batteries and other fields, and have good development prospects. They also play a vital role in traditional industries such as chlor-alkali industry, heavy metal recovery, water treatment, and hydrometallurgy, and have received widespread attention.

[0003] The development of water electrolysis hydrogen production technology is a breakthrough in the supply of low-carbon clean hydrogen, and will become an important field to support the development of high-proportion new energy and build a hydrogen-electricity synergy in the future. Anion exchange membrane water electrolysis (AEM) is considered to be a highly promising hydrogen production technology due to its unique advantages of low cost and high efficiency. At present, most of the anion exchange membranes used for water electrolysis adopt ammonium salt structure. However, this type of anion exchange membrane has the defect of degradation of core functional groups. For example, ammonium salt molecules are prone to degradation reactions such as Hofmann elimination under strong alkaline conditions, thereby inactivating anion exchange polymers and reducing chemical stability. Secondly, due to the high water absorption rate of ammonium salt anion exchange membranes, the mechanical properties are reduced. Thirdly, the transmission speed of hydroxide is much slower than that of protons, resulting in its ion conductivity being lower than that of proton exchange membranes represented by Nafion.

[0004] In summary, although the anion exchange polymers or anion exchange membranes currently on the market have good chemical stability, their mechanical strength and ionic conductivity still cannot meet the needs of special application scenarios, especially in large-scale applications. Strong mechanical strength and high ionic conductivity directly determine the durability and efficiency of devices such as alkaline fuel cells, water electrolysis, carbon dioxide reduction, and flow batteries. Therefore, it is necessary to develop an anion exchange polymer with excellent mechanical strength, high ionic conductivity, and high chemical stability to improve the performance of related electrochemical devices. Summary of the invention

[0005] The purpose of the present invention is to provide a class of anion exchange polymers containing zwitterionic side chain structures and applications thereof. Anion exchange polymers containing zwitterionic side chain structures can be used to make anion exchange membranes and anion exchange polymer membranes, while having excellent mechanical strength, high ionic conductivity and high chemical stability, and are particularly suitable for alkaline water electrolysis scenarios.

[0006] To achieve the above objectives, in a first aspect, the technical solution provides an anion exchange polymer with a zwitterionic side chain structure, comprising: a main chain structure and a zwitterionic side chain structure grafted on the main chain structure, wherein the zwitterionic side chain structure comprises a negatively charged sulfonate group, at least one positively charged ammonium salt, and n carbon chains connecting the ammonium salt and the sulfonate group, wherein n is an integer not less than 1, and wherein the main chain structure is a polymer having an anion exchange effect.

[0007] Preferably, the negatively charged sulfonate group is located at the terminal position of the zwitterionic side chain-containing structure.

[0008] Embodiment 1:

[0009] The ammonium salt on the zwitterion side chain structure is a quaternary ammonium salt. In this case, the zwitterion side chain structure is a quaternary ammonium salt-sulfonate zwitterion. The structure of the zwitterion side chain structure is shown in formula (1):

[0010] ;

[0011] Where R in formula (1) 1 It is the main chain structure of the polymer.

[0012] Embodiment 2:

[0013] The ammonium salt on the zwitterion side chain structure is an imidazole salt. In this case, the zwitterion side chain structure is an imidazole ammonium salt-sulfonate zwitterion. The structure of the zwitterion side chain structure is shown in formula (2):

[0014] .

[0015] Preferably, R in formula (2) 2 It is the main chain structure of the polymer.

[0016] Preferably, R in formula (2) 3 , R 4 , R 5It is a molecular structure with a certain chain length, and the molecular structure is selected from any one or a combination of at least two of methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-bromomethane, 1-bromoethane, 1-bromopropane, 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-ethylene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

[0017] Embodiment three:

[0018] The ammonium salt on the zwitterion side chain structure is a pyridinium salt. In this case, the zwitterion side chain structure is a pyridinium salt-sulfonate zwitterion. The structure of the zwitterion side chain structure is shown in formula (3):

[0019] .

[0020] Preferably, R in formula (3) 6 It is the main chain structure of the polymer.

[0021] Embodiment 4:

[0022] The ammonium salt on the zwitterion side chain structure is a cyclic ammonium salt. In this case, the zwitterion side chain structure is a cyclic quaternary ammonium salt-sulfonate zwitterion represented by a cyclic piperidine salt-sulfonate. The structure of the zwitterion side chain structure is shown in formula (4) and (5):

[0023] .

[0024] Preferably, R in formula (4) 7 It is the main chain structure of the polymer.

[0025] Embodiment five:

[0026] The ammonium salt on the zwitterion side chain structure is quinuclidine ammonium salt. In this case, the zwitterion side chain structure is a cyclic quaternary ammonium salt-sulfonate zwitterion represented by a cyclic piperidine salt-sulfonate. The structure of the zwitterion side chain structure is shown in formula (6):

[0027] .

[0028] Regarding the main chain structure of the polymers in Examples 1 to 5:

[0029] In some cases, the main chain structure of the polymer is selected from one or a combination of polystyrene, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polyethylene glycol, polysulfone, polyethylene, polypropylene, polynorbornene. Preferably, at this time, the present scheme grafts a positively charged ammonium salt side chain of a certain chain length at other positions of the main chain structure, wherein the number of ammonium salts is o, o is an integer greater than or equal to 0, and the types of ammonium salt side chains include but are not limited to one or more combinations of pyridinium ammonium salts, imidazole ammonium salts, piperidinium salts, and quaternary ammonium salts. It is worth mentioning that the grafted ammonium salt side chains are positively charged.

[0030] At this time, the ammonium salt side chain on the main chain structure is the same as the zwitterionic side chain structure (4), (5), (6), and the corresponding ammonium salt side chain chemical structure is as follows (7), (8), (9):

[0031] .

[0032] The schematic chemical formula for the connection between the main chain structure of formula (7), (8) and (9) and the zwitterionic side chain structure is shown below: .

[0033] Preferably, R in formula (7), (8), (9) 1， R 2， R 3， R 4， R 5， R 6， R 7， R 8 Each is independently selected from any one or a combination of at least two of methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-bromomethane, 1-bromoethane, 1-bromopropane, 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-ethylene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

[0034] In Example 4 and Example 5, the main chain structure of the polymer comprises an ammonium salt structure selected from one or a combination of a cyclic ammonium salt structure and a quinine ammonium salt structure, and a main chain structural unit having an anion exchange effect, wherein the ammonium salt structure is selected from one or a combination of two or more of the cyclic ammonium salt structure and the quinine ammonium salt structure represented by structural formula (10) and / or formula (11) and / or formula (12):

[0035] .

[0036] Specifically, the R 8 and R 9Each is independently selected from any one of hydrogen, C1-C10 chain alkyl or C3-C10 cycloalkyl.

[0037] Specifically, the R 8 Any one selected from hydrogen, methyl, ethyl, propyl, butyl, pentyl, phenyl or hexyl.

[0038] Specifically, the R 9 Any one selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol.

[0039] Specifically, X in the formula (7) - It is an anion.

[0040] Specifically, X in formula (10) - Selected from OH - , Cl - Br - ,I - , BF 4 - , HCO 3 - Any one of, more preferably OH - .

[0041] Specifically, X in formula (10) - OH - The ion exchange capacity of the anion exchange polymer is 0.1~10mmol / g.

[0042] Specifically, X in formula (11) - It is an anion.

[0043] Preferably, in formula (11), n ​​is an integer from 0 to 10.

[0044] Preferably, X in formula (11) - Selected from OH - , Cl - Br - ,I - , BF 4 - , HCO 3 - Any one of, more preferably OH - .

[0045] Preferably, X in formula (11) - OH - The ion exchange capacity of the anion exchange polymer is 0.1~10mmol / g.

[0046] Specifically, the R 10 Any one selected from hydrogen, C1-C10 chain alkyl or C3-C10 cycloalkyl.

[0047] Preferably, the R 10 Any one selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol.

[0048] Specifically, X in formula (12) - It is an anion.

[0049] Specifically, X in formula (12) - Selected from OH - , Cl - Br - ,I - , BF 4 - , HCO 3 - Any one of, more preferably OH - .

[0050] Specifically, X in formula (12) - OH - The ion exchange capacity of the anion exchange polymer is 0.1~10mmol / g.

[0051] .

[0052] In particular, the main chain structure of the polymer includes a tetraphenylmethane structural unit shown in formula (13), a 9,9'-spirobifluorene structural unit shown in formula (14), a triptycene structural unit shown in formula (15), a trifluoromethyl structural unit shown in formula (16), an aromatic hydrocarbon structural unit shown in formula (17) and formula (18), a fluorene structural unit shown in formula (19), a carbazole structural unit shown in formula (20), and at least one of a diphenylalkane structural unit shown in formula (21) and a triphenylbenzene structural unit shown in formula (22):

[0053] Preferably, R in formula (16) 1Any one or a combination of at least two selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-bromomethane, 1-bromoethane, 1-bromopropane, 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-ethylene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

[0054] This scheme provides several schematic chemical formulas for connecting the main chain structure of polymers with zwitterionic side chain ions as shown in the following formulas (23), (24), and (25):

[0055]

[0056] .

[0057] Preferably, n in formula (17) is an integer from 0 to 10.

[0058] Preferably, R in formula (16) 2 and R 3 Each is independently selected from any one of hydrogen, C1-C10 chain alkyl or C3-C10 cycloalkyl.

[0059] Preferably, R in formula (19) 2 and R 3 Any one or a combination of at least two selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-bromomethane, 1-bromoethane, 1-bromopropane, 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-ethylene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

[0060] Preferably, R in formula (20) 4 Any one or a combination of at least two selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and phenyl, methanol, 1-ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-bromomethane, 1-bromoethane, 1-bromopropane, 1-bromobutane, 1-bromopentane, 1-bromohexane, 1-bromoheptane, 1-bromooctane, 1-ethylene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

[0061] Preferably, n in formula (21) is an integer from 0 to 10.

[0062] In the second aspect, the above-prepared anion exchange polymer containing a zwitterionic side chain structure can be applied to a water treatment device, a gas separator or the preparation of anion exchange polymers.

[0063] In particular, anion exchange polymers are used in alkaline water electrolysis scenarios. The anion exchange membrane, cathode hydrogen evolution catalyst, and anode oxygen evolution catalyst are bonded together. The anion exchange membrane separates the hydrogen evolution catalyst and the oxygen evolution catalyst in the middle, and then they are assembled into an electrolytic cell to achieve electrolysis of alkaline water.

[0064] In a third aspect, the present invention provides a method for preparing a side chain of an anion exchange polymer containing a zwitterionic side chain structure, comprising the following steps:

[0065] (1) The main chain structure is obtained through polymerization reaction, wherein the polymerization reaction refers to one of free radical polymerization, coordination polymerization, cationic polymerization and superacid polymerization.

[0066] In the super acid polymer, preferably, the solvent of the polymerization reaction includes any one or a combination of at least two of dichloromethane, chloroform, tetrachloroethane, toluene, trifluoroacetic acid or trifluoromethanesulfonic acid.

[0067] Preferably, the polymerization reaction is carried out in the presence of a catalyst, wherein the catalyst comprises any one or a combination of at least two of trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, pentafluoropropionic acid or heptafluorobutyric acid; Preferably, the polymerization reaction temperature is -20 to 80 o C;.

[0068] Preferably, the polymerization reaction time is 0.1 to 120 h.

[0069] (2) After obtaining a polymer having a structure of tertiary amine, piperidine, pyridine, imidazole or a combination thereof as the end of the side chain terminal group, a certain amount of propane sultone is added, dissolved in a DMSO solution, the temperature is raised to 60 degrees, and the reaction is carried out for 12 hours.

[0070] (2) The obtained reaction solution was dripped into diethyl ether dropwise to obtain a polymer precipitate, which was then washed with ethyl acetate and water for multiple times to obtain an anion exchange polymer with a zwitterionic side chain.

[0071] In a fourth aspect, the present invention provides an anion exchange membrane and a method for preparing the same. The anion exchange membrane is prepared by dissolving the above-mentioned anion exchange polymer containing a zwitterionic side chain structure in a solution and solidifying it or processing it on a cast film machine, or by blending the anion exchange polymer containing a zwitterionic side chain structure with other polymer materials and then dissolving it in a solution and solidifying it or processing it on a cast film machine. The polymer material is, for example, polyphenylene ether, polytetrafluoroethylene, polyvinyl alcohol, polysulfone, etc. (including but not limited to other anion exchange polymers, such as polyimidazole salt anion exchange polymers, polypiperidine tertiary amine anion polymers, etc.).

[0072] Preferably, the solvent for dissolving the anion exchange membrane is a polar solvent, including any one or a combination of at least two of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, glycerol or water.

[0073] Preferably, the anion exchange polymer solution is cast or flow-casted onto a substrate and then dried.

[0074] Preferably, the substrate comprises any one or a combination of at least two of a glass plate, a polytetrafluoroethylene plate, a ceramic plate, a steel belt, a polyethylene terephthalate-based film, a polyamide-based film, a polytetrafluoroethylene porous film, a polyethylene porous film, a polypropylene porous film, glass fiber or carbon fiber.

[0075] Preferably, the drying temperature is one temperature in the range of 80 to 280 °C or multiple temperature stage drying.

[0076] Preferably, the drying time is 0.1 to 120 hours.

[0077] Preferably, the anion exchange polymer is placed in a cast film machine to prepare a flat film. In some embodiments, the specific thickness of the film is 1-500 μm.

[0078] In a fifth aspect, the present invention provides a type of anion exchange polymer adhesive containing a zwitterionic side chain structure and a preparation method thereof. The anion exchange polymer containing a zwitterionic side chain structure is dissolved in a solvent to prepare an anion exchange polymer solution, wherein the solvent includes any one or a combination of at least two of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, glycerol or water, and the anion exchange polymer solution is sprayed or dripped on a metal substrate catalyst or mixed with a powder catalyst and then sprayed or dripped on a metal substrate or a carbon-based conductive substrate to prepare the anion exchange polymer solution.

[0079] Preferably, the substrate includes nickel mesh, nickel fiber felt, nickel foam, stainless steel mesh, stainless steel felt, stainless steel foam, titanium mesh, titanium fiber felt, titanium foam, copper mesh, PTFE-based magnetron sputtered copper, copper sheet, carbon paper, carbon cloth, etc.

[0080] The anion exchange membrane and anion exchange polymer adhesive provided by the scheme can be used in alkaline water electrolysis, alkaline fuel cells, carbon dioxide reduction and liquid flow batteries.

[0081] Compared with the prior art, the present technical scheme provides an anion exchange polymer containing a zwitterionic side chain structure, wherein the anion exchange polymer comprises a main chain structure and a zwitterionic side chain structure of a sulfonate group with a negative charge grafted on the main chain structure, an ammonium salt with a positive charge, and a carbon chain connecting the ammonium salt and the sulfonate group, thereby obtaining an anion exchange polymer having a zwitterionic side chain structure including at least one or more combinations of quaternary ammonium salt-sulfonate zwitterions, imidazolium salt-sulfonate zwitterions, cyclic quaternary ammonium salt-sulfonate zwitterions represented by cyclic piperidinium salt-sulfonates, and pyridinium salt-sulfonate zwitterions.

[0082] The reason why the anion exchange polymer with zwitterionic side chain structure provided in this scheme can show high chemical stability is that the sulfonate group is a negative ion group, which has a repulsive effect on the hydroxide group, making it more difficult for the hydroxide group to approach the ammonium salt group, thereby reducing the probability of degradation. Figure 3 As shown, the ionic conductivity of the anion exchange membrane after long-term treatment in 1 M potassium hydroxide solution at 80 degrees Celsius did not show obvious decay.

[0083] The reason why the anion exchange polymer with zwitterionic side chain structure provided by this scheme can show high ionic conductivity is that the content of zwitterionic on the side chain of the anion exchange polymer membrane is regulated, so that the hydroxide ions are accelerated to pass through under the action of electrostatic repulsion. After experimental testing, the ionic conductivity of the anion exchange polymer with zwitterionic side chain structure provided by this scheme is 54 mS / cm at room temperature and 80 o C can reach 147mS / cm. Under the action of the electric field, the hydroxide overcomes the repulsive barrier of the sulfonic acid group. When passing through the water channel of the hydrophilic phase, its repulsive effect becomes an accelerating effect to a certain extent, which speeds up the transfer of hydroxide. Therefore, the performance of the anion exchange membrane in the device is very good, achieving 1A / cm at a cell voltage of 1.58V. 2 of current density.

[0084] The reason why the anion exchange polymer with zwitterionic side chain structure provided by this scheme can show excellent mechanical strength is due to the electrostatic effect of sulfonate and ammonium salt between molecular chains. The electrostatic effect makes the molecular chains cross-linked through the force of sulfonate anions and ammonium salt cations, and the increase of cross-linking density enhances the mechanical strength of the polymer. After experimental testing, the tensile strength of the anion exchange polymer with zwitterionic side chain structure provided by this scheme is as high as 185Mpa. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 This is the H NMR spectrum of the anion exchange polymer obtained in Example 5 of the present invention.

[0086] Figure 2 It is a mechanical property diagram of Examples 1 to 6 of the present invention and Comparative Example 1. The test temperature is room temperature and the film is in a dry state.

[0087] Figure 3 It is the ion conductivity test diagram of Examples 1 to 6 of the present invention and Comparative Example 1. The test temperature is 80 degrees Celsius.

[0088] Figure 4 This is a stability test of the ion conductivity of the anion exchange polymers obtained in Examples 1 to 6 of the present invention. They were continuously immersed in a 1M KOH solution at 80 degrees Celsius.

[0089] Figure 5 It is a schematic diagram of a membrane electrode electrolytic cell for electrolyzing water.

[0090] Figure 6 This is the application of the anion exchange membrane obtained in Example 4 in a water electrolysis device.

[0091] Figure 7 This is the mechanism by which zwitterions increase the speed and stability of ion transport. DETAILED DESCRIPTION

[0092] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0093] Embodiment 1:

[0094] The ammonium salt containing the zwitterionic side chain structure is a quaternary ammonium salt, and the main chain structure of the polymer is a cyclic ammonium salt structure and a main chain structural unit structure, and the structure is shown in the following formula (26):

[0095]

[0096] The preparation method of this type of anion is as follows:

[0097]

[0098] 1) Weigh 10 mmol polyethyleneimine into a 100 mL flask, add 20 mmol propane sultone, and then add 20 mmol iodomethane. Add 10 mL dimethyl sulfoxide, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ethanol solvent to precipitate a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0099] 2) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour it into a glass petri dish with a diameter of 6 cm after it is fully dissolved. Dry it at 120°C to form a membrane, and then peel the membrane from the glass. The anion exchange membrane is immersed in a 1M KOH solution and ion exchange is performed at 80°C for 12 hours to obtain an anion of OH. - of alkaline membrane.

[0100] Embodiment 2:

[0101] The ammonium salt on the zwitterionic side chain structure is an imidazole salt, and the main chain structure of the polymer is a cyclic ammonium salt structure and a main chain structural unit structure, and the structure is shown in the following formula (27):

[0102] (27)

[0104] The preparation method of the anion is as follows:

[0105]

[0106] 1) Weigh 10 mmol vinylimidazole monomer and 20 mmol styrene monomer in a 100 mL flask, add 10 mL dimethyl sulfoxide and 0.1 mmol azobisisobutyronitrile and react at 60°C for 4 hours. Pour the reaction product into an ethanol solvent to precipitate a yellow precipitate, then wash it with ethyl acetate three times, wash it with water and dry it to obtain a polymer.

[0107] 2) Weigh 10 mmol of the above polymer in a 100 mL flask, add 20 mmol of propane sultone, and then add 20 mmol of iodomethane. Add 10 mL of dimethyl sulfoxide, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ethanol solvent to precipitate a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0108] 3) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour into a glass petri dish with a diameter of 6 cm after fully dissolving. Dry at 120°C to form a membrane, and peel the membrane from the glass. Immerse the anion exchange membrane in 1M KOH solution and perform ion exchange at 80°C for 12 hours to obtain an anion of OH - of alkaline membrane.

[0109] Embodiment three:

[0110] The ammonium salt on the zwitterionic side chain structure is a pyridinium salt, and the main chain structure of the polymer is a cyclic ammonium salt structure and a main chain structural unit structure, and the structure is shown in the following formula (28):

[0111]

[0112] The preparation method of this type of anion is as follows:

[0113]

[0114] 1) Weigh 10 mmol vinylpyridine monomer and 20 mmol styrene monomer in a 100 mL flask, add 10 mL dimethyl sulfoxide and 0.1 mmol azobisisobutyronitrile and react at 60°C for 4 hours. Pour the reaction product into an ethanol solvent to precipitate a yellow precipitate, then wash it with ethyl acetate three times, then wash it with water and dry it to obtain a polymer.

[0115] 2) Weigh 10 mmol of the above polymer in a 100 mL flask, add 20 mmol of propane sultone, and then add 20 mmol of iodomethane. Add 10 mL of dimethyl sulfoxide, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ethanol solvent to precipitate a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0116] 3) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour into a glass petri dish with a diameter of 6 cm after fully dissolving. Dry at 120°C to form a membrane, and peel the membrane from the glass. Immerse the anion exchange membrane in 1M KOH solution and perform ion exchange at 80°C for 12 hours to obtain an anion of OH - of alkaline membrane.

[0117] Embodiment 4:

[0118] The ammonium salt on the zwitterionic side chain structure is a cyclic ammonium salt, and the main chain structure of the polymer is a cyclic ammonium salt structure and a main chain structural unit structure, and the structure is shown in the following formula (29):

[0119]

[0120] The preparation method of this type of anion is as follows:

[0121] 1) Weigh 2.00 g (8.68 mmol) of terphenyl in a 100 mL flask, add 1.17 g (10.32 mmol) of N-methyl-4-piperidone, add tetraphenylmethane (0.26 mmol), add 9,9'-spirobifluorene (0.09 mmol), and then add 8.8 mL of dichloromethane to dissolve the reactants. Add 1.5 mL of trifluoroacetic acid and 8.8 mL of trifluoromethanesulfonic acid at 0°C and react for 6 hours. Pour the viscous purple product into 1M (mol / L) K 2 CO 3 The mixture was immersed in the solution at room temperature for 24 hours, filtered to obtain a white solid product, which was fully washed with deionized water and dried to obtain the target product.

[0122] 2) Quaternization reaction and preparation of zwitterionic side chains. Weigh 500 mg of the above intermediate polymer, add 10 mL of dimethyl sulfoxide, then add 1473.2 mg of methyl iodide and 752.38 mg of propane sultone, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ether solvent containing ethanol (the volume ratio of ether to ethanol is 6:1), precipitate to obtain a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0123] 3) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour it into a glass petri dish with a diameter of 6 cm after it is fully dissolved. Dry it at 120°C to form a membrane, and then peel the membrane from the glass. Immerse the anion exchange membrane in 1M KOH solution and exchange ions at 80°C for 12 hours to obtain an anion of OH- of alkaline membrane.

[0124] The obtained anion exchange polymer was characterized and analyzed using a Bruker AVANCE III HD (500MHz) nuclear magnetic resonance spectrometer. The hydrogen spectrum nuclear magnetic resonance diagram is shown in Figure 1 Deuterated dimethyl sulfoxide (d6-DMSO) was used to dissolve the samples in the test.

[0125]

[0126] Example 5 provides a structure in which the ammonium salt on the zwitterionic side chain structure is a cyclic ammonium salt, the main chain structure of the polymer is a cyclic ammonium salt structure and a main chain structural unit, and the structure is as follows:

[0127]

[0128] The preparation method of this type of anion is as follows:

[0129] 1) Weigh 2.00 g (8.68 mmol) of terphenyl in a 100 mL flask, add 1.17 g (10.32 mmol) of N-methyl-4-piperidone, add triptycene (0.26 mmol), add 9,9'-spirobifluorene (0.09 mmol), and then add 8.8 mL of dichloromethane to dissolve the reactants. Add 1.5 mL of trifluoroacetic acid and 8.8 mL of trifluoromethanesulfonic acid at 0°C and react for 6 hours. Pour the viscous purple product into 1M (mol / L) K 2 CO 3 The mixture was immersed in the solution at room temperature for 24 hours, filtered to obtain a white solid product, which was fully washed with deionized water and dried to obtain the target product.

[0130] 2) Quaternization reaction and preparation of zwitterionic side chains. Weigh 500 mg of the above intermediate polymer, add 10 mL of dimethyl sulfoxide, then add 1473.2 mg of methyl iodide and 752.38 mg of propane sultone, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ether solvent containing ethanol (the volume ratio of ether to ethanol is 6:1), precipitate to obtain a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0131] 3) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour it into a glass petri dish with a diameter of 6 cm after it is fully dissolved. Dry it at 120°C to form a membrane, and then peel the membrane from the glass. The anion exchange membrane is immersed in a 1M KOH solution and ion exchange is performed at 80°C for 12 hours to obtain an anion of OH - of alkaline membrane.

[0132]

[0133] Embodiment 6

[0134] The ammonium salt on the zwitterionic side chain structure is a cyclic ammonium salt, and the main chain structure of the polymer is a cyclic ammonium salt structure and a structure of the main chain structural unit, and the structure is as follows:

[0135]

[0136] The preparation method of this type of anion is as follows:

[0137]

[0138] 1) Weigh 2.00 g (8.68 mmol) of terphenyl in a 100 mL flask, add 10.32 mmol of 3-quinuclidine, add triptycene (0.33 mmol), add 9,9'-spirobifluorene (0.89 mmol), and then add 8.8 mL of dichloromethane to dissolve the reactants. Add 1.5 mL of trifluoroacetic acid and 8.8 mL of trifluoromethanesulfonic acid at room temperature and react for 6 hours. Pour the viscous purple product into 1M (mol / L) K 2 CO 3 The mixture was immersed in the solution at room temperature for 24 hours, filtered to obtain a white solid product, which was fully washed with deionized water and dried to obtain the target product.

[0139] 2) Quaternization reaction and preparation of zwitterionic side chains. Weigh 500 mg of the above intermediate polymer, add 10 mL of dimethyl sulfoxide, then add 1473.2 mg of methyl iodide and 752.38 mg of propane sultone, react at room temperature for 12 hours, then raise the temperature to 60°C and react for 4 hours. Pour the reaction product into an ether solvent containing ethanol (the volume ratio of ether to ethanol is 6:1), precipitate to obtain a yellow precipitate, then wash it three times with ethyl acetate, wash it with water and dry it to obtain an anion of I - anion exchange polymer.

[0140] 3) Membrane formation and ion exchange. Weigh 120 mg of the above anion exchange polymer, add 5 mL of dimethyl sulfoxide, and pour it into a glass petri dish with a diameter of 6 cm after it is fully dissolved. Dry it at 120°C to form a membrane, and then peel the membrane from the glass. Immerse the anion exchange membrane in 1M KOH solution and exchange ions at 80°C for 12 hours to obtain an anion of OH - of alkaline membrane.

[0141] Comparative Example 1

[0142] This solution provides an anion exchange polymer Sustainion ® 37-50-grade T, produced by Dioxidematerials.

[0143] Performance tests of Examples 1 to 4 and Comparative Example 1:

[0144] The following performance tests were conducted on the chemical formula (26) in Example 1, the chemical formula (27) in Example 2, the chemical formula (28) in Example 3, the chemical formula (29) in Example 4, the chemical formula (30) in Example 5, the chemical formula (31) in Example 6, and the comparative example 1:

[0145] 1) Ion exchange capacity test

[0146] The ion exchange capacity of the anion exchange membrane was measured using the H spectrum in the nuclear magnetic resonance test, as follows: a Bruker AVANCE NEO (500MHz) nuclear magnetic resonance spectrometer was used to characterize and analyze the obtained anion exchange polymer, and the hydrogen peak on the methyl group attached to the quaternary ammonium nitrogen and the hydrogen peak on the main chain benzene ring were integrated respectively, and the ion exchange capacity was calculated by the peak area ratio of the two.

[0147] 2) Tensile strength test

[0148] The tensile strength of the anion exchange membrane at room temperature was measured using a tensile testing machine (manufacturer: Shimadzu Corporation, model: AGS-X10KN). Figure 2 .

[0149] 3) Ionic conductivity test

[0150] Measurement of OH in pure water by four-electrode electrochemical impedance spectroscopy - Ionic conductivity, the specific test parameters are as follows: Take an area of ​​2 x 2cm 2 , the membrane material with a thickness of 25μm was tested by using Autolab 302N electrochemical workstation at a frequency of 0.1Hz~1000ΚHz, and the ionic conductivity was calculated by fitting the curve to obtain the test graph as shown in Figure 3 .

[0151] 4) Stability test

[0152] The residual cation rate in the anion exchange membrane was measured by immersing the anion exchange membrane in a 1 M NaOH solution at 80°C and observing the changes in the H NMR spectrum after 2000 h.

[0153] Take the chemical formula (26) in Example 1, the chemical formula (27) in Example 2, the chemical formula (28) in Example 3, the chemical formula (29) in Example 4, the chemical formula (30) in Example 5, and the chemical formula (31) in Example 6 and perform the following alkaline electrolyzed water test to obtain the test graph as shown below: Figure 4 .

[0154] 5) Application of the anion exchange membranes of Examples 1 to 6 and Comparative Example 1 in alkaline electrolyzed water.

[0155] The following alkaline electrolyzed water tests were performed using chemical formula (26) in Example 1, chemical formula (27) in Example 2, chemical formula (28) in Example 3, chemical formula (29) in Example 4, chemical formula (30) in Example 5, chemical formula (31) in Example 6, and Comparative Example 1:

[0156] The specific structure of the MEA electrolytic cell is shown in the attached Figure 5 As shown: component ① stainless steel pad; component ② copper electrode; component ③ graphite cathode electrolyte flow chamber; component ④ cathode catalyst; component ⑤ ion transport membrane; component ⑥ anode catalyst.

[0157] This test uses NiFeOOH / nickel mesh as the anode gas diffusion electrode (1.0 cm 2 ), with Pt / C cloth as cathode gas diffusion electrode (1.0 cm 2 ), the membrane electrode assembly (MEA) was assembled into the device using the selected anion exchange membrane as the membrane material. 100 mL min was continuously introduced into the anode and cathode. −1 The electrolytic cell was operated at room temperature, 40°C, 60°C, and 80°C, respectively, using an Autolab 30 2 N test performance. Before the polarization curve test, the cyclic voltammetry (CV) was used for activation for 1 h, the voltage range was 1.0 ~ 2.6 V, and the scan rate was 200 mV s−1. The voltage range used for the polarization curve test was 1.0 ~ 2.6 V, and the scan rate was 10 mV s−1. Figure 6 :

[0158] The results show that the anion exchange membrane represented by the chemical formula (28) in Example 4 exhibits excellent current density at room temperature, 40°C, 60°C, and 80°C at a cell voltage of 2.4V, and is at the forefront of the reported anion exchange membrane alkaline water electrolysis performance. At a cell voltage of 2.0V and 80°C, the current density of the MEA device based on the anion exchange membrane shown in Example 1 is 5.2A / cm 2 , showing a current density of 3.2 A / cm higher than that of the MEA device based on the anion exchange membrane shown in Comparative Example 1 Sustainion X37-50 Grade T 2 The superior performance of the anion exchange membrane represented by the chemical formula (28) in Example 4 was demonstrated.

[0159] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. Anion exchange polymers with zwitterionic side chain structures, It is characterized in that include: The main chain structure and the zwitterionic side chain structure grafted on the main chain structure, the structure of the zwitterionic side chain structure is shown in formula (6): ； Wherein n and m are integers not less than 1; The main chain structure of the polymer comprises an ammonium salt structure selected from one or a combination of cyclic ammonium salt structure and quinine ammonium salt structure and a main chain structural unit having an anion exchange effect, wherein the ammonium salt structure is selected from one or a combination of two or more of the structural formulas (10), (11) and (12) of the cyclic ammonium salt structure and the quinine ammonium salt structure: 。 2. The anion exchange polymer having a zwitterionic side chain structure according to claim 1, It is characterized in that The main chain structure of the polymer is selected from one or a combination of polystyrene, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polyethylene glycol, polysulfone, polyethylene, polypropylene, and polynorbornene.

3. The anion exchange polymer having a zwitterionic side chain structure according to claim 1, It is characterized in that The main chain structure of the polymer includes at least one of a tetraphenylmethane structural unit shown in formula (13), a 9,9'-spirobifluorene structural unit shown in formula (14), a triptycene structural unit shown in formula (15), a trifluoromethyl structural unit shown in formula (16), an aromatic hydrocarbon structural unit shown in formula (17) and formula (18), a fluorene structural unit shown in formula (19), a carbazole structural unit shown in formula (20), a diphenylalkane structural unit shown in formula (21), and a triphenylbenzene structural unit shown in formula (22): 。 4. The anion exchange polymer having a zwitterionic side chain structure according to claim 1, It is characterized in that Positively charged ammonium salt side chains of a certain length are grafted at other positions of the main chain structure, wherein the number of ammonium salts is o, o is an integer greater than or equal to 0, and the types of ammonium salt side chains include one or more combinations of pyridinium salts, imidazole salts, piperidinium salts, and quaternary ammonium salts.

5. The anion exchange polymer having a zwitterionic side chain structure according to claim 1, It is characterized in that The structure is as follows: 。 6. An anion exchange polymer having a zwitterionic side chain structure, It is characterized in that The structure is as follows: 。 7. An anion exchange polymer having a zwitterionic side chain structure, It is characterized in that The structure is as follows: 。 8. An anion exchange membrane, It is characterized in that The anion exchange polymer with zwitterionic side chain structure described in any one of claims 1 to 5, 6, and 7 is dissolved in a solution and solidified or processed by a cast film machine, or the anion exchange polymer with zwitterionic side chain structure described in any one of claims 1 to 5 is blended with other polymer materials and then dissolved in a solution and solidified or processed by a cast film machine.

9. An anion exchange polymer binder, It is characterized in that An anion exchange polymer solution is prepared by dissolving an anion exchange polymer with a zwitterionic side chain structure described in any one of 1 to 5, 6, and 7 in a solvent, wherein the solvent includes any one or a combination of at least two of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, glycerol or water, and the anion exchange polymer solution is sprayed or dripped on a metal substrate catalyst or mixed with a powder catalyst and then sprayed or dripped on a metal substrate or a carbon-based conductive substrate to obtain the anion exchange polymer solution.

10. Use of the anion exchange membrane according to claim 8, It is characterized in that Used in alkaline water electrolysis, alkaline fuel cells, carbon dioxide reduction and flow batteries.

11. Use of the anion exchange polymer binder according to claim 9, It is characterized in that Used in alkaline water electrolysis, alkaline fuel cells, carbon dioxide reduction and flow batteries.

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