Anion exchange polymer with high alkali-resistant stability, anion exchange membrane, method and application

Abstract

The invention provides an anion exchange polymer with high alkali-resistant stability, an anion exchange membrane, a method and application, by introducing a cationic group (3-quinuclidinone hydrochloride or 3-quinuclidinone) with high alkali resistance into a polymer skeleton structure, the alkali-resistant stability is improved while the high ionic conductivity of the anion exchange membrane is maintained; aryl groups (such as biphenyl, p-terphenyl, m-terphenyl, diphenylethane or 9, 9-dimethyl fluorene) in the polymer provide multiple choices, and customized design can be carried out according to different application scenes and performance requirements; after the alkali-resistant group is introduced, the polymer still keeps high ionic conductivity, and efficient operation of an electrochemical device is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular to an anion exchange polymer with high alkali resistance and stability, an anion exchange membrane, a method and an application. Background Art

[0002] Anion exchange membrane is a membrane material that can selectively conduct anions. It has broad application prospects in electrochemical devices such as water electrolysis to produce hydrogen, alkaline fuel cells, flow batteries and electrodialyzers. However, there are relatively few anion exchange membranes with excellent comprehensive performance on the market, especially in terms of alkali resistance and stability, which are difficult to meet the needs of practical applications. Therefore, the development of an anion exchange membrane with high ion conductivity and excellent alkali resistance and stability has become a hot topic in current research.

[0003] In order to meet the above needs, researchers are constantly exploring new anion exchange membrane materials. Among them, an ideal anion exchange membrane material should have high chemical stability to operate stably for a long time in a strong alkaline environment. At the same time, the material should also have excellent ionic conductivity to ensure the efficient operation of the electrochemical device.

[0004] Although some existing anion exchange membrane preparation technologies have made certain progress, such as anion exchange polymers disclosed in certain patents and their preparation methods and applications, the chemical stability of anion exchange membranes prepared by these technologies still needs to be improved. In particular, in the assembly process of actual battery stacks, higher requirements are placed on the alkali resistance stability of membrane materials. Therefore, future research needs to continue to explore new anion exchange membrane materials to further improve their comprehensive performance and meet the practical application needs of electrochemical devices. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an anion exchange polymer, anion exchange membrane, method and application with high alkali resistance and stability, which improves the alkali resistance and stability while maintaining the high ion conductivity of the anion exchange membrane by introducing highly alkali-resistant cationic groups into the polymer skeleton structure.

[0006] To achieve the above object, the present invention provides the following technical solution: an anion exchange polymer with high alkali resistance and stability, the general structural formula of which is as follows:

[0007] Among them, part A is an aromatic group, and the value of x ranges from 50 to 100.

[0008] Furthermore, the aromatic group is one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylethane, and 9,9-dimethylfluorene.

[0009] Furthermore, the value range of x is 85~100.

[0010] Furthermore, X - OH - or halogen anions or HCO3 ⁻ .

[0011] The present invention also provides a method for preparing an anion exchange polymer with high alkali resistance and stability, and the specific steps are as follows: The aromatic compound, 3-quinuclidine hydrochloride or 3-quinuclidine and trifluoroacetophenone are mixed in a solvent, Lewis acid is added to catalyze the reaction at 0°C, and excess reactants are removed to obtain an intermediate polymer; The intermediate polymer, potassium carbonate and methyl iodide are mixed in a solvent and reacted at room temperature to obtain a mixture 4; The mixture 4 was poured into ethyl acetate to obtain a precipitate, and the precipitate was washed to obtain an anion exchange polymer.

[0012] Further, the structural formula of the anion exchange polymer is as follows:

[0013] Among them, part A is an aromatic group, and the aromatic group is one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylethane, and 9,9-dimethylfluorene; x is determined according to the molar ratio of 3-quinuclidine hydrochloride or 3-quinuclidine and trifluoroacetophenone, and the value range is 50~100.

[0014] The present invention also provides an anion exchange membrane with high alkali resistance and stability, which is prepared by the anion exchange polymer.

[0015] Furthermore, an anion exchange polymer solution with a solid content of 1wt%-40wt% is placed in a mold and allowed to stand and dry to form a membrane, and after demoulding, the membrane is immersed in an ion exchange solution to obtain an anion exchange membrane with the desired anion.

[0016] Furthermore, the ion exchange solution contains OH - , halogen anions or ‌HCO3 ⁻ of solution.

[0017] The present invention also provides an electrochemical device, which adopts the above-mentioned anion exchange membrane with high alkali resistance stability.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides an anion exchange polymer with high alkali resistance and stability. By introducing a highly alkali-resistant cationic group (3-quinuclidine hydrochloride or 3-quinuclidine) into the polymer skeleton structure, the alkali resistance and stability of the polymer are significantly improved, so that it can operate stably for a long time in a highly alkaline environment; the aromatic groups in the polymer (such as biphenyl, p-terphenyl, m-terphenyl, diphenylethane or 9,9-dimethylfluorene) provide a variety of options, and can be customized according to different application scenarios and performance requirements; after the introduction of the alkali-resistant group, the polymer still maintains a high ion conductivity, ensuring the efficient operation of the electrochemical device. The present invention can prepare a polymer with a specific structure and performance by precisely controlling the raw material ratio and reaction conditions, thereby improving the quality and consistency of the product.

[0019] The present invention provides an anion exchange membrane with high alkali resistance stability. By introducing a highly alkali-resistant cationic group (3-quinuclidine hydrochloride or 3-quinuclidine) into the polymer skeleton structure, the alkali resistance stability of the polymer is significantly improved, so that it can operate stably for a long time in a highly alkaline environment; through a simple solution casting and ion exchange process, an anion exchange membrane with high alkali resistance stability can be prepared, reducing production costs and complexity. In addition, the anion exchange membrane of the present invention has high ion conductivity, ensuring that ions in an electrochemical device can be efficiently transferred, and can also maintain stable performance for a long time in a highly alkaline environment, thereby extending the service life of the membrane. The electrochemical device of the present invention adopts the anion exchange membrane with high alkali resistance and stability of the present invention. The device can operate efficiently and stably for a long time in a high alkaline environment, thereby improving the reliability and durability of the device. Due to the high alkali resistance and stability and high ion conductivity, the electrochemical device can be applied to various fields, such as liquid flow energy storage batteries, anion exchange membrane water electrolysis hydrogen production equipment, alkaline anion exchange membrane fuel cells, etc., providing new impetus and possibilities for the development and progress of electrochemical technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the OH of the anion exchange membrane of the embodiment of the present invention at 80°C - Plot of ionic conductivity data.

[0021] Figure 2 The OH value of the anion exchange membrane of the embodiment of the present invention after alkali immersion at 80°C for 2000 hours - Ionic conductivity retention data graph. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the present invention, unless otherwise specified, all the embodiments and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0024] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0025] In the present invention, unless otherwise specified, percentage (%) or part refers to the weight percentage or weight part relative to the composition.

[0026] In the present invention, unless otherwise specified, the components or preferred components involved can be combined with each other to form a new technical solution.

[0027] In the present invention, unless otherwise specified, the numerical range "a-b" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "6-22" represents that all real numbers between "6-22" are listed in this document, and "6-22" is just an abbreviation of these numerical combinations.

[0028] The “range” disclosed in the present invention is in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0029] In the present invention, the term "and / or" used herein refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0030] In the present invention, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0031] Unless otherwise specified, the professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to the present invention.

[0032] The present invention provides an anion exchange membrane with high alkali resistance and stability, and the skeleton structure is as follows:

[0033] The present invention improves the alkali resistance stability while maintaining the high ion conductivity of the anion exchange membrane by introducing a highly alkali-resistant cationic group (the red frame portion of the structural formula below) into the polymer skeleton structure.

[0034]

[0035] In the general formula of the skeleton structure, part A is an aromatic group, and the aromatic group can be: biphenyl, p-terphenyl, m-terphenyl, diphenylethane, 9,9-dimethylfluorene, etc.

[0036] The value range of x is 50~100, preferably 85~100.

[0037] X is an anion, which can be OH - or halogen anions or HCO3 ⁻ ; The present invention provides a method for preparing an anion exchange membrane with high alkali resistance and stability, which is specifically as follows: (1) Friedel-Crafts alkylation reaction to obtain an intermediate polymer.

[0038] Under the catalysis of Lewis acid (trifluoromethanesulfonic acid and trifluoroacetic acid), aromatic compounds, 3-quinuclidine hydrochloride or 3-quinuclidine and trifluoroacetophenone react. During the reaction, the hydrogen atoms on the benzene ring of the aromatic compound are replaced by the alkyl group of quinuclidine, forming a new CC bond, and obtaining a polymer chain containing a quinuclidine structure, i.e., an intermediate polymer. Specifically: Mixing an aromatic compound, 3-quinuclidinone hydrochloride or 3-quinuclidinone and trifluoroacetophenone in a solvent to obtain a mixture 1; At 0°C, trifluoromethanesulfonic acid and trifluoroacetic acid were added to mixture 1, and the mixture was stirred for 6 hours to obtain a viscous mixture 2; Add 1M K2CO3 solution to mixture 2 (K2CO3 is used to neutralize unreacted trifluoromethanesulfonic acid and trifluoroacetic acid and promote the precipitation of the product), soak at room temperature for 24 hours, filter to obtain a white solid product, wash it thoroughly with deionized water and dry it to obtain an intermediate polymer; (2) Synthesis of functionalized polymers.

[0039] In an alkaline environment, the intermediate polymer undergoes a nucleophilic substitution reaction with a halogen compound, and the halogen anion is introduced into the polymer chain to form a functionalized polymer, namely an anion exchange polymer. Specifically: The intermediate polymer was dissolved in a solvent, potassium carbonate was added after it was completely dissolved, and the mixture was reacted at 60° C. for 16 hours to obtain a mixture 3; Add iodomethane to mixture 3 and react at room temperature for 24 h to obtain mixture 4; The mixture 4 was poured into ethyl acetate to precipitate a yellow precipitate, which was washed with ethyl acetate several times and then washed with water and dried to obtain an anion exchange polymer, wherein the anion is I - ; Preferably, the mass ratio of the intermediate polymer to the solvent is (1-10):100; the amount of potassium carbonate and methyl iodide added exceeds 25% of the amount of the intermediate polymer added; (3) Film formation, cross-linking and ion exchange.

[0040] Dissolving an anion exchange polymer in a solvent to obtain an anion exchange polymer solution having a solid content of 1 wt % to 40 wt %; The anion exchange polymer solution is placed in a mold for drying, and then immersed in a KOH solution after demoulding. The anions obtained by ion exchange are OH - anion exchange membrane.

[0041] Example 1: x=85

[0042] (1) Synthesis of intermediate polymers.

[0043] Weigh 1.54g (10.0mmol) of biphenyl in a 100mL three-necked flask, add 1.37g (8.5mmol) of 3-quinuclidine hydrochloride and 0.26g of trifluoroacetophenone (1.5mmol), and add 10mL of dichloromethane to dissolve the reactants. Add 12mL of trifluoromethanesulfonic acid and 1mL of trifluoroacetic acid at 0℃, and react for 6 hours with mechanical stirring. Pour the viscous product into 1M K2CO3 solution, soak at room temperature for 24 hours, filter to obtain a white solid product, wash it thoroughly with deionized water and dry it, and obtain a polymer chain containing a quinuclidine structure, i.e., an intermediate polymer, with the following structure: .

[0044] (2) Synthesis of functionalized polymers.

[0045] Weigh 1.2g of the intermediate polymer in a 100mL single-necked flask, add 15mL of dimethyl sulfoxide, and add 150μL of trifluoroacetic acid to promote the dissolution of the polymer. After it is completely dissolved, add 0.36g of potassium carbonate and react at 60°C for 16 hours. Then add 300μL of iodomethane and react at room temperature for 24 hours. Pour the reaction product into ethyl acetate to precipitate a yellow precipitate, wash it with ethyl acetate several times, then wash it with water and dry it to obtain an anion of I - of functionalized polymers.

[0046] (3) Film formation and cross-linking film formation.

[0047] Weigh 1 g of the anion exchange polymer, add 50 mL of dimethyl sulfoxide, and pour into the groove of a flat glass plate after fully dissolving. Dry at 80° C. for 48 hours to form a membrane, thereby obtaining an anion exchange membrane.

[0048] After the membrane was peeled off from the glass plate, it was immersed in 1M KOH solution and ion exchanged at room temperature for 48 hours to obtain anions of OH. - The OH content of the fully wet anion exchange membrane in pure water was measured by four-electrode electrochemical impedance spectroscopy. - Ionic conductivity. Figure 1 As shown, the ionic conductivity of the anion exchange membrane obtained in this embodiment is 174 mS / cm at 80°C; Figure 2 As shown in the figure, the ion conductivity retention rate of the anion exchange membrane obtained in this embodiment after alkali immersion for 2000 hours is 96.2%. The introduction of alkali-resistant cations enables the anion exchange membrane to maintain high ion conductivity while showing excellent alkali resistance stability.

[0049] Example 2: x=50 The amounts of 3-quinuclidinone hydrochloride and trifluoroacetophenone in Example 1 were adjusted to 5 mmol and 5 mmol, respectively, and the obtained product structural formula was:

[0050] like Figure 1 As shown, the ionic conductivity of the anion exchange membrane obtained in this embodiment at 80°C is 157 mS / cm; Figure 2 As shown, the ion conductivity retention rate of the anion exchange membrane obtained in this embodiment after alkali leaching for 2000 hours is 92.9%.

[0051] Example 3: x=100 The amounts of 3-quinuclidinone hydrochloride and trifluoroacetophenone in Example 1 were adjusted to 10 mmol and 0 mmol, respectively, and the obtained product structural formula was:

[0052] like Figure 1 As shown, the ionic conductivity of the anion exchange membrane obtained in this embodiment at 80°C is 138 mS / cm. Figure 2 As shown, the ion conductivity retention rate of the anion exchange membrane obtained in this embodiment after alkali leaching for 2000 hours is 93.4%.

[0053] Example 4: x=85 The biphenyl in Example 1 was replaced with 2.30 g (10.0 mmol) of p-terphenyl, and 3-quinuclidinone hydrochloride was replaced with 3-quinuclidinone. The product structure was as follows:

[0054] like Figure 1 As shown, the ionic conductivity of the anion exchange membrane obtained in this embodiment is 170 mS / cm at 80°C; Figure 2 As shown, the ion conductivity retention rate of the anion exchange membrane obtained in this embodiment after alkali leaching for 2000 hours was 97.5%.

[0055] Example 5: x=85 The biphenyl in Example 1 was replaced with a combination of 80% p-terphenyl and 20% m-terphenyl in A, and the product structure was:

[0056] Example 6: x=85 The biphenyl in Example 1 is replaced by a combination of 80% p-terphenyl and 20% diphenylethane, and the product structure is:

[0057] Example 7: x=85 The biphenyl in Example 1 was replaced with a combination of A of 90% p-terphenyl + 10% dimethylfluorene, and the obtained product structure was:

[0058] In summary, the anion exchange membrane of the present invention has excellent alkali resistance stability and high ion conductivity, and can be widely used in various electrochemical devices, such as liquid flow energy storage batteries, anion exchange membrane water electrolysis hydrogen production equipment, alkaline anion exchange membrane fuel cells, etc. The expansion of these application fields provides new impetus and possibilities for the development and progress of electrochemical technology. The anion exchange membrane and polymer of the present invention have little impact on the environment during preparation and use, which conforms to the concept of sustainable development. At the same time, due to the improvement of alkali resistance stability, the waste generated by membrane aging or damage is reduced, which is beneficial to environmental protection and has significant technical advantages and application prospects.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anion exchange polymer with high alkali resistance stability, characterized in that The general structure is as follows: Among them, part A is an aromatic group, and the value of x ranges from 50 to 100.

2. The anion exchange polymer with high alkali stability according to claim 1, characterized in that: The aromatic group is one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylethane, and 9,9-dimethylfluorene.

3. The anion exchange polymer with high alkali stability according to claim 1, characterized in that: The value range of x is 85~100.

4. The anion exchange polymer with high alkali stability according to claim 1, characterized in that: X - OH - or halogen anions or HCO3 ⁻ .

5. A method for preparing an anion exchange polymer with high alkali resistance and stability, characterized in that: The specific steps are as follows: The aromatic compound, 3-quinuclidine hydrochloride or 3-quinuclidine and trifluoroacetophenone are mixed in a solvent, Lewis acid is added to catalyze the reaction at 0°C, and excess reactants are removed to obtain an intermediate polymer; The intermediate polymer, potassium carbonate and methyl iodide are mixed in a solvent and reacted at room temperature to obtain a mixture 4; The mixture 4 was poured into ethyl acetate to obtain a precipitate, and the precipitate was washed to obtain an anion exchange polymer.

6. The method for preparing an anion exchange polymer with high alkali resistance stability according to claim 5, characterized in that: The structural formula of anion exchange polymer is as follows: Among them, part A is an aromatic group, and the aromatic group is one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylethane, and 9,9-dimethylfluorene; x is determined according to the molar ratio of 3-quinuclidine hydrochloride or 3-quinuclidine and trifluoroacetophenone, and the value range is 50~100.

7. An anion exchange membrane with high alkali resistance stability, characterized in that: The method is prepared by using the anion exchange polymer described in any one of claims 1 to 4.

8. The anion exchange membrane with high alkali resistance stability according to claim 7, characterized in that: An anion exchange polymer solution with a solid content of 1wt%-40wt% is placed in a mold and allowed to stand and dry to form a film. After demoulding, the film is immersed in an ion exchange solution to obtain an anion exchange membrane with the required anions.

9. The anion exchange membrane with high alkali resistance stability according to claim 8, characterized in that: The ion exchange solution contains OH - , halogen anions or ‌HCO3 ⁻ of solution.

10. An electrochemical device, characterized in that: An anion exchange membrane with high alkali resistance stability as described in any one of claims 7 to 9 is used.

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