An anion exchange membrane, a method for preparing the same, and use thereof
By combining polyaryl biphenyl polymer with LDH nanosheets of a specific size into anion exchange membrane, the stability and ion conductivity issues of anion exchange membranes under strong alkali and high temperature were solved, and a high-performance composite membrane suitable for alkaline water electrolysis to produce hydrogen was prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-16
- Publication Date
- 2026-06-16
Smart Images
Figure CN122214958A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of alkaline water electrolysis for hydrogen production, and particularly to an anion exchange membrane, its preparation method, and its application. Background Technology
[0002] Alkaline water electrolysis is one of the mainstream technologies for large-scale, low-cost production of "green hydrogen." The membrane, as the core component of the electrolyzer, functions to conduct hydroxide ions, prevent cross-mixing of hydrogen and oxygen, and physically separate the electrodes. Traditional alkaline electrolyzers typically use porous membranes (such as composite membranes based on polysulfone / ZrO2), whose ion conduction depends on the pores filled by the electrolyte, resulting in an inherent contradiction between gas barrier properties and ion conductivity.
[0003] Anion exchange membranes are dense polymer membranes containing fixed cation groups (such as quaternary ammonium groups) that can selectively conduct anions (OH-). - Compared to porous membranes, an ideal anion exchange membrane can theoretically achieve high ion conductivity while providing better gas barrier properties due to its dense structure, thus potentially improving the current density, energy efficiency, and gas purity of the electrolyzer. However, existing anion exchange membranes face challenges under strong alkaline and high-temperature electrolysis conditions: firstly, quaternary ammonium groups are prone to degradation in concentrated alkali, leading to a decrease in ion conductivity; secondly, there is still room for improvement in the ion conductivity of simple polymer membranes.
[0004] Introducing inorganic fillers into polymer matrices is a common strategy for improving the overall performance of membrane materials. The addition of inorganic fillers can act as physical crosslinking points, reinforcing phases, and barrier layers, helping to suppress swelling, improve mechanical properties, and extend gas diffusion paths. However, the introduction of inorganic fillers is often accompanied by problems such as blocked ion conduction channels and defects caused by poor interfacial compatibility. Therefore, how to prepare anion exchange membranes with synergistically optimized ion conductivity, gas barrier properties, mechanical strength, and chemical stability is a pressing technical problem to be solved in this field. Summary of the Invention
[0005] This invention addresses the shortcomings and deficiencies of existing anion exchange membranes used in alkaline water electrolysis in terms of long-term stability and ion conductivity. It provides an anion exchange membrane prepared by a casting solution formed from a specific polyaryl biphenyl polymer matrix resin combined with specific layered double hydroxide (LDH) nanosheet inorganic filler. This membrane not only exhibits excellent ion conductivity but also superior mechanical strength and alkali-resistant chemical stability, making it suitable for alkaline water electrolysis hydrogen production systems. It also helps reduce electrolyzer voltage and improve operational durability.
[0006] Another object of the present invention is to provide a method for preparing anion exchange membranes.
[0007] Another object of the present invention is to provide an application of anion exchange membrane in the field of alkaline water electrolysis for hydrogen production.
[0008] Another object of the present invention is to provide an alkaline water electrolysis device.
[0009] In a first aspect, the present invention protects an anion exchange membrane comprising a polyaryl biphenyl polymer matrix containing cationic functional groups and layered double metal hydroxide nanosheets dispersed in the matrix, wherein the thickness of the LDH nanosheets is 5-20 nm and the lateral dimension is 100-1000 nm.
[0010] According to the anion exchange membrane protected by the present invention, preferably, the LDH nanosheets are composed of a mixture of two LDH nanosheets with different lateral dimensions, wherein the average lateral dimension D1 of the smaller LDH nanosheets and the average lateral dimension D2 of the larger LDH nanosheets satisfy: D2 / D1>5.
[0011] According to the anion exchange membrane protected by the present invention, preferably, the average lateral dimension D1 of the small-sized LDH nanosheets is 20~100nm, and the average lateral dimension D1 of the large-sized LDH nanosheets is 100~1000nm.
[0012] According to the anion exchange membrane protected by the present invention, preferably, the mass ratio of the small-sized LDH nanosheets to the large-sized LDH nanosheets is (1~2):(2~9).
[0013] According to the anion exchange membrane protected by the present invention, preferably, the mass ratio of the LDH nanosheets to the polyarylbiphenyl polymer matrix is (5~20):(30~50).
[0014] According to the anion exchange membrane protected by the present invention, preferably, the polyaryl biphenyl polymer matrix is selected from one or more of polybiphenylpiperidine, triphenylmethane-modified polybiphenylpiperidine, dibromohexane-crosslinked polyterphenylpiperidine, cyanuric chloride-crosslinked polybiphenylpiperidine, polyarylquinine, hyperbranched pyrene-polyterphenylpiperidine, and poly(terphenyl-fluorene-piperidine).
[0015] According to the anion exchange membrane protected by the present invention, preferably, the LDH nanosheets are selected from at least one of magnesium aluminum hydrotalcite, zinc aluminum hydrotalcite, nickel iron hydrotalcite, and calcium aluminum hydrotalcite.
[0016] Secondly, the present invention also specifically protects a method for preparing anion exchange membrane, comprising the following steps: The polyaryl biphenyl polymer matrix is dispersed and dissolved in a dispersant, LDH nanosheets are added, and the mixture is stirred for 2-5 hours to form a casting solution, thus preparing a film.
[0017] According to the preparation method of the anion exchange membrane protected by the present invention, preferably, the dispersant is selected from at least one of N-methylpyrrolidone, dichloromethane, dimethyl sulfoxide, and N,N-dimethylformamide.
[0018] According to the preparation method of the anion exchange membrane protected by the present invention, preferably, the amount of the dispersant is 30-65% of the mass of the casting solution.
[0019] Thirdly, the present invention also specifically protects the application of anion exchange membrane in the field of alkaline water electrolysis for hydrogen production.
[0020] Fourthly, the present invention also specifically protects an alkaline water electrolysis device, including the anion exchange membrane as a diaphragm assembly.
[0021] Beneficial effects: This invention provides an anion exchange membrane that uses a specific alkali-resistant polyaryl biphenyl polymer as a substrate and is composited with LDH nanosheets of a specific size. This allows the inorganic filler LDH nanosheets to be well dispersed in the polymer matrix and exert a synergistic reinforcing effect, thereby obtaining a high-performance composite anion exchange membrane with high ionic conductivity, low swelling ratio and good mechanical properties. It can be widely used in the field of alkaline water electrolysis for hydrogen production. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0023] Figure 1 This is a scanning electron microscope (SEM) image of the cross-section of the anion exchange membrane prepared in Example 1. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0025] In a specific embodiment, the present invention provides an anion exchange membrane comprising a polyaryl biphenyl polymer matrix containing cationic functional groups and layered double metal hydroxide nanosheets dispersed in the matrix, wherein the thickness of the LDH nanosheets is 5-20 nm and the lateral dimension is 100-1000 nm.
[0026] It should be noted that: The anion exchange membrane of the present invention uses a specific alkali-resistant polyaryl biphenyl polymer as a substrate and is composited with LDH nanosheets of a specific size, so that the inorganic filler LDH nanosheets are well dispersed in the polymer matrix and play a synergistic reinforcing role, thereby obtaining a high-performance composite anion exchange membrane.
[0027] LDH nanosheets have a suitable aspect ratio, making them easier to orient in the film plane under shear forces (such as during the coating process), which helps to reduce the resistance to in-plane ion transport.
[0028] To further optimize the microstructure and performance of the membrane, in some specific embodiments, the LDH nanosheets dispersed in the matrix mentioned in this invention can preferably be combined LDH nanosheets, which are composed of two different lateral sizes of LDH nanosheets. The average lateral size D1 of the small-sized LDH nanosheets and the average lateral size D2 of the large-sized LDH nanosheets satisfy: D2 / D1>5.
[0029] The LDH nanosheet filler system employs a dual-size distribution, where the larger filler mainly serves as a mechanical reinforcing framework, while the smaller filler fills the spaces between large particles and polymer chain segments, thereby refining the structure, increasing density, and enhancing gas barrier properties.
[0030] In some specific embodiments, in the combined LDH nanosheets mentioned in this invention, the average lateral dimension D1 of the small-sized LDH nanosheets is 20~100nm, and the average lateral dimension D1 of the large-sized LDH nanosheets is 100~1000nm.
[0031] In some specific embodiments, the present invention further controls the mass ratio of small-sized LDH nanosheets to large-sized LDH nanosheets to be (1~2):(2~9).
[0032] For example, in some specific exemplary embodiments, the mass fraction of small-sized LDH nanosheets can be 1 part or 2 parts, and the mass fraction of large-sized LDH nanosheets can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or any other range of values.
[0033] For example, in some specific exemplary embodiments, LDH nanosheets can be selected as follows: Combination 1: LDH nanosheets (nickel-iron hydrotalcite), 5% by mass (of which 5 nm thick and 20-100 nm laterally account for 10%; 20 nm thick and 100-1000 nm laterally account for 90%).
[0034] Combination 2: LDH nanosheets (nickel-iron hydrotalcite), 20% by mass (of which 10 nm thick and 20-100 nm lateral dimensions account for 20%; 20 nm thick and 100-1000 nm lateral dimensions account for 80%).
[0035] Combination 3: LDH nanosheets (nickel-iron hydrotalcite), 10% by mass (of which 5 nm thick and 20-100 nm laterally account for 15%; 15 nm thick and 100-1000 nm laterally account for 85%).
[0036] Combination 4: LDH nanosheets (nickel-iron hydrotalcite), 15% by mass (of which 8 nm thick and 20-100 nm laterally account for 12%; 18 nm thick and 100-1000 nm laterally account for 88%).
[0037] Combination 5: LDH nanosheets (nickel-iron hydrotalcite), 8% by mass (of which 10 nm thick, 20-100 nm lateral dimension, account for 18%; 20 nm thick, 100-1000 nm lateral dimension, account for 82%).
[0038] Combination 6: LDH nanosheets (nickel-iron hydrotalcite), mass fraction 18% (of which 6 nm thickness and 20-100 nm lateral dimensions account for 16%; 15 nm thickness and 100-1000 nm lateral dimensions account for 84%).
[0039] In some specific embodiments, the mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix mentioned in this invention is (5~20):(30~50). For example, the mass of LDH nanosheets can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, or any other range of values, and the mass of polyarylbiphenyl polymer matrix can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or any other range of values.
[0040] The anion exchange membrane of the present invention uses polyarylbiphenyl polymer as a continuous matrix, with inorganic LDH nanosheets uniformly dispersed therein. By further adjusting the mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix, the enhancement effect and processing performance can be better balanced. While enhancing stability and ion conduction performance, the membrane embrittlement problem can be better avoided, and the mechanical strength can be enhanced.
[0041] In some specific exemplary embodiments, the polyaryl biphenyl polymer matrix mentioned in this invention is selected from one or more of the following: polybiphenylpiperidine, triphenylmethane-modified polybiphenylpiperidine, dibromohexane-crosslinked polyterphenylpiperidine, cyanuric chloride-crosslinked polybiphenylpiperidine, polyarylquinine, hyperbranched pyrene polyterphenylpiperidine, and poly(terphenyl-fluorene-piperidine).
[0042] The polyaryl biphenyl polymer matrix selected in the embodiments of the present invention can have better alkali resistance.
[0043] In some specific exemplary embodiments, the LDH nanosheets mentioned in this invention are selected from at least one of magnesium aluminum hydrotalcite, zinc aluminum hydrotalcite, nickel iron hydrotalcite, and calcium aluminum hydrotalcite.
[0044] The aforementioned preferred LDH nanosheets exhibit excellent chemical stability in a strongly alkaline environment, and their surface properties facilitate their bonding with the polymer matrix, making it more advantageous to prepare composite membranes with good stability.
[0045] In a specific embodiment, the present invention also specifically protects a method for preparing anion exchange membrane, comprising the following steps: The polyaryl biphenyl polymer matrix is dispersed and dissolved in a dispersant, LDH nanosheets are added, and the mixture is stirred for 2-5 hours to form a casting solution, thus preparing a film.
[0046] In some specific exemplary embodiments, the dispersant mentioned in this invention may be selected from at least one of N-methylpyrrolidone (NMP), dichloromethane (DCM), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF).
[0047] In some specific exemplary embodiments, the content of the dispersant mentioned in the present invention in the casting solution can preferably be controlled to be 30-65% of the mass of the casting solution, for example, it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, etc.
[0048] In some specific exemplary embodiments, to further promote better dispersion of the polyarylbiphenyl polymer matrix in the dispersant, the dispersion and dissolution of the polyarylbiphenyl polymer matrix can be achieved by stirring at 60-80°C until complete dissolution. Adding LDH nanosheets and stirring for 2-5 hours can further promote the formation of a uniform and stable slurry system.
[0049] In specific embodiments, in order to promote uniform dispersion of LDH nanosheets, high-speed shearing or ultrasonic treatment can also be used to achieve uniform dispersion and obtain a stable and homogeneous casting solution.
[0050] In the preparation method of the anion exchange membrane of the present invention, the casting solution can be cast onto a flat substrate (such as glass or polyester film) by casting or blade coating, and the final anion exchange membrane is obtained after controlled solvent evaporation and drying.
[0051] In a specific embodiment, the present invention also provides an application of anion exchange membrane in the field of alkaline water electrolysis for hydrogen production.
[0052] In a specific embodiment, the present invention further provides an alkaline water electrolysis device, including the anion exchange membrane as a diaphragm assembly.
[0053] The anion exchange membrane of the present invention serves as an ion-selective membrane separating the anode and cathode chambers, and can efficiently conduct OH- in the device. - The ions effectively block the penetration of H2 and O2, thereby ensuring the safe, efficient and stable operation of the electrolyzer under high current density and producing high-purity hydrogen.
[0054] Example 1 An anion exchange membrane includes a polyarylbiphenyl polymer matrix (polybiphenylpiperidineonium) and LDH nanosheets dispersed in the matrix.
[0055] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 5 nm and a lateral dimension of 20-100 nm, accounting for 10%; and the other with a thickness of 20 nm and a lateral dimension of 100-1000 nm, accounting for 90%.
[0056] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 5:30.
[0057] This embodiment 1 also provides a method for preparing anion exchange membrane, comprising the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, 5% by mass; Polymer (polyphenylpiperidine): 30% by mass; Dispersant (NMP): 65% by mass.
[0058] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 70°C for about 5 hours until completely dissolved to obtain a transparent viscous solution.
[0059] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 2 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0060] Example 2 An anion exchange membrane includes a polyarylbiphenyl polymer matrix (triphenylmethane-modified polybiphenylpiperidinium) and LDH nanosheets dispersed in the matrix.
[0061] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 10 nm and a lateral dimension of 20~100 nm, accounting for 20%; and the other with a thickness of 20 nm and a lateral dimension of 100~1000 nm, accounting for 80%.
[0062] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 20:50.
[0063] This embodiment 2 also provides a method for preparing anion exchange membrane, including the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, 20% by mass; Polymer (triphenylmethane-modified poly(biphenylpiperidinium)): 50% by mass; Dispersant (DCM): 30% by mass.
[0064] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 65°C for about 4 hours until completely dissolved to obtain a transparent viscous solution.
[0065] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 4 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0066] Example 3 An anion exchange membrane includes a polyarylbiphenyl polymer matrix (poly(terphenylpiperidine) crosslinked with dibromohexane) and LDH nanosheets dispersed in the matrix.
[0067] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 5 nm and a lateral dimension of 20-100 nm, accounting for 15%; and the other with a thickness of 15 nm and a lateral dimension of 100-1000 nm, accounting for 85%.
[0068] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 10:30.
[0069] This embodiment 3 also provides a method for preparing anion exchange membrane, including the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, 10% by mass; Polymer (dibromohexane-crosslinked poly(terphenylpiperidineonium)): 30% by mass; Dispersant (DCM): 60% by mass.
[0070] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 70°C for about 3 hours until completely dissolved to obtain a transparent viscous solution.
[0071] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 3 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0072] Example 4 An anion exchange membrane includes a polyarylbiphenyl polymer matrix (polybiphenylpiperidineonium crosslinked with cyanuric chloride) and LDH nanosheets dispersed in the matrix.
[0073] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 8 nm and a lateral dimension of 20-100 nm, accounting for 12%; and the other with a thickness of 18 nm and a lateral dimension of 100-1000 nm, accounting for 88%.
[0074] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 15:40.
[0075] This embodiment 4 also provides a method for preparing anion exchange membrane, comprising the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, 15% by mass; Polymer (crosslinked cyanuric chloride polybis(piperidinium)): 40% by mass; Dispersant (DCM): 45% by mass.
[0076] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 60°C for about 3 hours until completely dissolved to obtain a transparent viscous solution.
[0077] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 5 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0078] Example 5 An anion exchange membrane includes a polyarylbiphenyl polymer matrix (polyarylquinine) and LDH nanosheets dispersed in the matrix.
[0079] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 10 nm and a lateral dimension of 20~100 nm, accounting for 18%; and the other with a thickness of 20 nm and a lateral dimension of 100~1000 nm, accounting for 82%.
[0080] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 20:50.
[0081] This embodiment 5 also provides a method for preparing anion exchange membrane, comprising the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, 8% by mass; Polymer (polyarylquinine): 35% by mass; Dispersant (DCM): 57% by mass.
[0082] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 80°C for about 3 hours until completely dissolved to obtain a transparent viscous solution.
[0083] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 2 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0084] Example 6 An anion exchange membrane includes a polyaryl biphenyl polymer matrix (hyperbranched pyrene polyterphenyl piperidine) and LDH nanosheets dispersed in the matrix.
[0085] LDH nanosheets (nickel-iron hydrotalcite) are composed of two types of LDH nanosheets with different lateral dimensions: one with a thickness of 6 nm and a lateral dimension of 20-100 nm, accounting for 16%; and the other with a thickness of 15 nm and a lateral dimension of 100-1000 nm, accounting for 84%.
[0086] The mass ratio of LDH nanosheets to polyarylbiphenyl polymer matrix is 20:50.
[0087] This embodiment 6 also provides a method for preparing anion exchange membrane, comprising the following steps: The formulation of the casting solution slurry is as follows: LDH nanosheets, mass fraction 18%; Polymer (hyperbranched pyrene-based poly(terphenylpiperidine): 45% by mass); Dispersant (DCM): 37% by mass.
[0088] Weigh the required amount of polymer powder and add it to the corresponding mass of dispersant. Stir mechanically at 60°C for about 2 hours until completely dissolved to obtain a transparent viscous solution.
[0089] Under continuous stirring, pre-dried LDH nanosheets were slowly added to the polymer solution. After all the nanosheets were added, stirring continued for 2 hours until the slurry was uniform, fine, and free of visible particles or agglomerates, thus obtaining the final casting solution slurry. The casting solution slurry was then cast onto a flat glass substrate. After controlled solvent evaporation and drying, the dispersant was removed, resulting in the final anion exchange membrane.
[0090] Example 7 An anion exchange membrane is basically the same as in Example 1, except that the added LDH nanosheets are of a single size. The LDH nanosheets (nickel-iron hydrotalcite) are 5 nm thick, with a lateral dimension of 20-100 nm, and account for 100%.
[0091] Comparative Example 1 An anion exchange membrane is basically the same as in Example 1, except that LDH nanosheets are not added.
[0092] Comparative Example 2 An anion exchange membrane is basically the same as in Example 1, except that the size of the added LDH nanosheets does not meet the requirements of this invention: the LDH nanosheets (nickel-iron hydrotalcite) are composed of two different types of LDH nanosheets with different lateral dimensions: one with a thickness of 2 nm and a lateral dimension of 10-20 nm, accounting for 10%; and the other with a thickness of 100 nm and a lateral dimension of 2000-3000 nm, accounting for 90%.
[0093] Result detection The performance of the anion exchange membranes in the above embodiments and comparative examples was tested. The specific testing methods are described below: Ionic conductivity (mS cm) -1 GB / T 20042.3-2022 Swelling rate (%): GB / T 20042.3-20222 Tensile strength (MPa): GB / T 20042.3-20222 The relevant test results are shown in Table 1: Table 1. Performance test results of anion exchange membranes in the examples and comparative examples Test Project Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Ionic conductivity 200 205 210 209 220 215 198 130 145 swelling rate 23 18 19 22 18 20 27 45 40 Tensile strength 65 75 70 68 72 70 60 72 68 Insulation performance Non-conductive Non-conductive Non-conductive Non-conductive Non-conductive Non-conductive Non-conductive Non-conductive Non-conductive As can be seen from the data in Table 1 above, the anion exchange membranes provided in Examples 1-7 of the present invention all exhibit good ionic conductivity, with values significantly higher than those of Comparative Examples 1 and 2. Furthermore, the swelling rates of Comparative Examples 1 and 2 are both 40% or higher, and the swelling rates of the anion exchange membranes in Examples 1-7 are also significantly higher than those of Comparative Examples 1 and 2. This indicates that the anion exchange membranes provided by the present invention possess good alkali-resistant chemical stability and can meet the performance requirements for application in the field of alkaline water electrolysis for hydrogen production.
[0094] Figure 1 The image shows a scanning electron microscope image of the anion exchange membrane of Example 1. As can be seen from the image, the main body of the membrane exhibits a dense structure. This dense structure can ensure that the anion exchange membrane has good alkali resistance, chemical stability and mechanical strength. The membrane interior shows obvious layered or wavy textures. The orientation structure of the polymer chain segments helps to optimize the ion transport channels and improve the ionic conductivity of the membrane.
[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. An anion exchange membrane, characterized in that, The invention comprises a polyaryl biphenyl polymer matrix containing cationic functional groups and layered bimetallic hydroxide nanosheets dispersed in the matrix, wherein the layered bimetallic hydroxide nanosheets have a thickness of 5-20 nm and a lateral dimension of 20-1000 nm.
2. The anion exchange membrane according to claim 1, characterized in that, The layered bimetallic hydroxide nanosheets are composed of a mixture of two types of layered bimetallic hydroxide nanosheets with different lateral dimensions. The average lateral dimension D1 of the smaller layered bimetallic hydroxide nanosheets and the average lateral dimension D2 of the larger layered bimetallic hydroxide nanosheets satisfy the condition: D2 / D1>5.
3. The anion exchange membrane according to claim 2, characterized in that, The average lateral dimension D1 of the small-sized layered bimetallic hydroxide nanosheets is 20~100nm, and the average lateral dimension D2 of the large-sized layered bimetallic hydroxide nanosheets is 100~1000nm.
4. The anion exchange membrane according to claim 2 or 3, characterized in that, The mass ratio of the small-sized layered bimetallic hydroxide nanosheets to the large-sized layered bimetallic hydroxide nanosheets is (1~2):(2~9).
5. The anion exchange membrane according to claim 4, characterized in that, The mass ratio of the layered bimetallic hydroxide nanosheets to the polyaryl biphenyl polymer matrix is (5~20):(30~50).
6. The anion exchange membrane according to claim 5, characterized in that, The polyaryl biphenyl polymer matrix is selected from one or more of the following: polybiphenylpiperidine, triphenylmethane-modified polybiphenylpiperidine, dibromohexane-crosslinked polyterphenylpiperidine, cyanuric chloride-crosslinked polybiphenylpiperidine, polyarylquinine, hyperbranched pyrene polyterphenylpiperidine, and poly(terphenyl-fluorene-piperidine).
7. The anion exchange membrane according to claim 5, characterized in that, The layered bimetallic hydroxide nanosheets are selected from at least one of magnesium aluminum hydrotalcite, zinc aluminum hydrotalcite, nickel iron hydrotalcite, and calcium aluminum hydrotalcite.
8. A method for preparing an anion exchange membrane according to any one of claims 1 to 7, characterized in that, Includes the following steps: The polyaryl biphenyl polymer matrix is dispersed and dissolved in a dispersant, layered bimetallic hydroxide nanosheets are added, and the mixture is stirred for 2-5 hours to form a casting solution, thus preparing a film.
9. The application of the anion exchange membrane according to any one of claims 1 to 7 in the field of alkaline water electrolysis for hydrogen production.
10. An alkaline water electrolysis device, characterized in that, The anion exchange membrane described in any one of claims 1 to 7 is used as a membrane assembly.