Anion exchange membrane, method for preparing the same, and use thereof

Abstract

The application discloses an anion exchange membrane, a preparation method and application thereof. The anion exchange membrane comprises a mixed polymer matrix and a small molecule capturing agent. The polymer matrix comprises connected aromatic ring-containing groups and nitrogen-containing groups. The nitrogen-containing groups comprise piperidine groups and / or quinine groups. The small molecule capturing agent comprises a piperidine nitroxide radical derivative. The anion exchange membrane has excellent anti-radical aging performance and good compatibility.

Description

Technical Field

[0001] This invention relates to the field of anion exchange membrane technology, specifically to an anion exchange membrane, its preparation method, and its application. Background Technology

[0002] Alkaline water electrolysis for hydrogen production is a core technology in the hydrogen energy industry. Anion exchange membranes (AEMs), as the core component of the electrolyzer, directly determine the electrolyzer's lifespan and operating efficiency. Currently, polyarylene piperidine resins, due to their excellent alkali stability, have become one of the mainstream choices for AEM matrix resins.

[0003] However, traditional polyarylpiperidine resins exhibit poor resistance to free radical aging. Existing technologies primarily employ two methods to enhance their resistance: one is the addition of inorganic free radical inhibitors (such as CeO2 and ZrO2 nanoparticles), and the other is the addition of conventional organic antioxidants (such as phenols and amines). However, anion exchange membranes prepared using these two methods generally suffer from poor compatibility and unstable anti-aging effects. Therefore, improving the free radical aging resistance of traditional anion exchange membranes while ensuring good compatibility and strong stability has become crucial. Summary of the Invention

[0004] The purpose of this invention is to provide an anion exchange membrane, its preparation method, and its application, thereby solving the problem of unstable electro-aging performance of existing anion exchange membranes.

[0005] To achieve the objectives of this invention, the following technical solution is provided: In a first aspect, the present invention provides an anion exchange membrane comprising a mixed polymer matrix and a small molecule scavenger, wherein the polymer matrix comprises connected aromatic ring groups and nitrogen-containing groups, the nitrogen-containing groups comprising piperidine groups and / or quinine groups, and the small molecule scavenger comprises piperidine nitric oxide radical derivatives.

[0006] In some embodiments, the polymer matrix comprises a first repeating unit and a second repeating unit connected together, the first repeating unit comprising a first aromatic ring group and the piperidine group connected together, and the second repeating unit comprising a second aromatic ring group and the quinine group connected together.

[0007] In some embodiments, the polymer matrix further comprises a first functional group attached to the piperidine group and / or the quinine group.

[0008] In some embodiments, the polymer matrix further comprises anionic groups, and both the first repeating unit and the second repeating unit are connected to the anionic groups.

[0009] In some embodiments, the first functional group includes one or more of hydrogen, alkyl, alkenyl, or alkynyl.

[0010] In some embodiments, the anionic group includes OH. - Cl - ,Br - HCO3 - NO3 - CF3COO - or CH3COO - One or more of them.

[0011] In some embodiments, the polymer matrix further includes a third repeating unit connecting the first repeating unit and / or the second repeating unit, the third repeating unit including a third aromatic ring group and a second functional group connected together.

[0012] In some embodiments, the aromatic ring group includes one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylmethane, 1,3,5-triphenylbenzene, triphenylmethane, tris(triphenylene), 9,9-dimethylfluorene, and 9,9-spirodifluorene.

[0013] In some embodiments, the piperidine nitric oxide radical derivatives include one or more of the following: 2,2,6,6-tetramethylpiperidine-1-ox radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-ox radical, 4-(2-bromoethoxy)-2,2,6,6-tetramethylpiperidine-1-ox radical, 4-(3-bromopropoxy)-2,2,6,6-tetramethylpiperidine-1-ox radical, and 4-chloromethyl-2,2,6,6-tetramethylpiperidine-1-ox radical.

[0014] In some embodiments, the mass ratio of the small molecule scavenger is 0.1% to 10% of the mass of the polymer matrix.

[0015] In some embodiments, the number-average molecular weight of the polymer matrix is ​​40,000 g / mol to 80,000 g / mol.

[0016] In some embodiments, the nitrogen-containing group is present in the polymer matrix at a concentration of 2 mmol / g to 3.0 mmol / g.

[0017] In a second aspect, the present invention provides a method for preparing an anion exchange membrane, for preparing an anion exchange membrane as described in the first aspect, the method comprising: dissolving a polymer matrix and a small molecule scavenger in a solvent to obtain a casting solution; coating the casting solution onto a mold, and obtaining an intermediate membrane material after degassing and drying; and subjecting the intermediate membrane material to ion exchange, washing with water, and drying to obtain an anion exchange membrane.

[0018] In some embodiments, the vacuum degree of degassing is -0.08MPa to -0.1MPa, the degassing time is 10min to 30min, the drying adopts a gradient temperature increase of 60℃ to 120℃, and the drying time is 6h to 24h.

[0019] In some embodiments, the concentration of the alkaline solution for ion exchange is 1 mol / L to 5 mol / L, the temperature for ion exchange is 25°C to 60°C, and the duration of ion exchange is 12 h to 24 h.

[0020] Thirdly, the present invention provides an application of an anion exchange membrane, which is used in alkaline water electrolysis for hydrogen production or in fuel cells.

[0021] The anion exchange membrane provided by this invention incorporates a small molecule scavenger containing piperidine nitric oxide radical derivatives into a polymer matrix. The two molecules are uniformly dispersed, allowing the small molecule scavenger to rapidly and efficiently capture reactive oxygen species, inhibiting the oxidative degradation of the anion exchange membrane. This avoids the problems of inorganic inhibitor aggregation and organic antioxidant migration. Furthermore, the small molecule scavenger in this anion exchange membrane does not aggregate or stratify, resulting in a smooth surface without significant defects, thus preventing leakage. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is the molecular structural formula of an anion exchange membrane according to one embodiment; Figure 2 This is a flowchart illustrating one method for preparing anion exchange membranes. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0026] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0027] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0028] The present invention provides an anion exchange membrane comprising a mixed polymer matrix and a small molecule scavenger. The polymer matrix contains connected aromatic ring groups and nitrogen-containing groups, the nitrogen-containing groups including piperidine groups and / or quinine groups, and the small molecule scavenger contains piperidine nitric oxide radical derivatives.

[0029] In a specific embodiment, the polymer matrix serves as the framework for constructing the anion exchange membrane. It is a high-molecular-weight polymer material with a stable long-chain structure and excellent film-forming properties, ensuring the overall mechanical strength, structural integrity, and molding stability of the exchange membrane. The small-molecule scavenger is a small-molecule functional organic compound adapted to the main polymer framework. As a free radical scavenger, compared to traditional inorganic inhibitors, the small-molecule scavenger exhibits significantly improved compatibility with the polymer matrix, achieving uniform dispersion at the molecular level and completely avoiding problems such as powder agglomeration, component migration, and precipitation failure.

[0030] In specific embodiments, the aromatic ring groups include one or more aromatic monomers such as biphenyl, p-terphenyl, m-terphenyl, diphenylmethane, 1,3,5-triphenylbenzene, triphenylmethane, tris(ethylene), 9,9-dimethylfluorene, and 9,9-spirodifluorene. Specifically, the aromatic ring groups in the molecular structure have high rigidity and excellent chemical stability, which can significantly improve the membrane's resistance to acid and alkali corrosion, high-temperature aging resistance, and dimensional stability, effectively inhibiting problems such as swelling, deformation, and damage of the membrane in the electrolyte environment.

[0031] In specific embodiments, the piperidine group is a nitrogen-containing heterocyclic functional group, and the quinine group is a bicyclic nitrogen-containing aromatic functional group. It should be noted that the piperidine group provides chemical stability, while the quinine group possesses excellent anion complexing ability, ion selectivity, and charge regulation performance. The nitrogen-containing heterocyclic groups are characterized by high activity and strong charge stability, enabling efficient adsorption and conduction of anions, providing a stable ion transport channel for the exchange membrane, and ensuring basic ion conduction capacity.

[0032] In specific embodiments, the piperidine nitroxide radical derivatives include one or more of the following: 2,2,6,6-tetramethylpiperidine-1-oxo radical (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxo radical, 4-(2-bromoethoxy)-2,2,6,6-tetramethylpiperidine-1-oxo radical, 4-(3-bromopropoxy)-2,2,6,6-tetramethylpiperidine-1-oxo radical, and 4-chloromethyl-2,2,6,6-tetramethylpiperidine-1-oxo radical. Preferably, the piperidine nitroxide radical derivative is 4-hydroxy-TEMPO, which has better compatibility with the polymer matrix, can achieve uniform molecular-level dispersion, and is free from agglomeration and migration precipitation.

[0033] In specific embodiments, the anion exchange membrane balances resistance to free radical aging, ion conductivity, and mechanical properties. Furthermore, the anion exchange membrane obtained through organic blending exhibits good compatibility, preventing aggregation and stratification. After accelerated aging for 100 hours in a mixed alkaline solution of 1 mol / L KOH and 10 mmol / L H₂O₂ at 80°C, the anion exchange membrane retains ≥85% of its conductivity and ≥87% of its ion exchange capacity. This anion exchange membrane has low manufacturing costs and can be used in energy conversion devices such as alkaline water electrolysis for hydrogen production and alkaline fuel cells.

[0034] The anion exchange membrane provided by this invention incorporates a small molecule scavenger containing piperidine nitric oxide radical derivatives into a polymer matrix. The two molecules are uniformly dispersed, allowing the small molecule scavenger to rapidly and efficiently capture reactive oxygen species, inhibiting the oxidative degradation of the anion exchange membrane. This avoids the problems of inorganic inhibitor aggregation and organic antioxidant migration. Furthermore, the small molecule scavenger in this anion exchange membrane does not aggregate or stratify, resulting in a smooth surface without significant defects, thus preventing leakage.

[0035] In some embodiments, the polymer matrix adopts a segmented copolymer structure, and the polymer matrix includes a first repeating unit connected in phase ( Figure 1 Part P1) and the second repeating unit ( Figure 1In the P2 section, the first repeating unit comprises a first aromatic ring group and a piperidine group connected in sequence, and the second repeating unit comprises a second aromatic ring group and a quinine group connected in sequence. Specifically, the polymer matrix may comprise a first segment and a second segment connected in sequence, the first segment comprising a plurality of sequentially connected first repeating units, and the second segment comprising a plurality of sequentially connected second repeating units.

[0036] In a specific embodiment, the first segment is formed by the sequential covalent polymerization of multiple structurally identical first repeating units. Each first repeating unit integrates and bonds a first aromatic ring-containing group and a piperidine group. The rigid structure of the first aromatic ring-containing group ensures the structural stability of the first repeating unit; the nitrogen-containing reactive structure of the piperidine group provides anti-aging properties to the polymer matrix. Optionally, the proportion of the first repeating units in the first segment can be x, where x is any number between 0.00 and 1.00.

[0037] In a specific embodiment, the second segment is formed by the sequential covalent polymerization of multiple structurally identical second repeating units. Each second repeating unit is composed of a second aromatic ring group bonded to a quinine group. The rigid structure of the second aromatic ring group ensures the structural stability of the second repeating unit. The unique cage-like bicyclic aza-structure of the quinine group enhances the anion-selective adsorption and ion exchange capacity of the polymer matrix. Optionally, the proportion of second repeating units in the second segment can be y, where y is any number between 0.00 and 1.00, and x and y are not simultaneously 0 or 1.

[0038] For some implementation methods, please refer to Figure 1 The polymer matrix also contains a first functional group ( Figure 1 The first functional group (R3, R4, R5) is attached to the piperidine group and / or quinine group. Specifically, the active nitrogen atom sites of both the piperidine group and the quinine group can serve as grafting sites for attaching the first functional group; the functional group bonded to the nitrogen atom of the piperidine group is defined as the first sub-functional group, and the functional group bonded to the nitrogen atom of the quinine group is defined as the second sub-functional group. The first sub-functional group and the second sub-functional group can be the same or different.

[0039] In a specific embodiment, the first functional group includes one or more of hydrogen, alkyl, alkenyl, or alkynyl groups. The first functional group can be used to regulate the charge density, steric hindrance, hydrophilicity / hydrophobicity, and structural stability of the piperidine and quinine groups, thereby optimizing the overall ion exchange performance and fouling resistance of the exchange membrane. Optionally, two first sub-functional groups may be attached to the nitrogen atom of the piperidine group, and one second sub-functional group may be attached to the nitrogen atom of the quinine group.

[0040] In some embodiments, the polymer matrix further comprises anionic groups, with both the first and second repeating units connected to anionic groups. Specifically, the piperidine and quinine groups in the polymer matrix are protonable and ionizable nitrogen-containing heterocyclic functional structures, capable of stably forming positively charged cationic active centers in solution systems, providing reliable bonding sites for the anionic groups. The anionic groups are stably bonded to the charged piperidine and quinine cations through ionic bonds, forming complete ion-pair structures.

[0041] In a specific embodiment, the anionic group includes OH. - Cl - ,Br - HCO3 - NO3 - CF3COO - or CH3COO - One or more of the following. Wherein, OH - and HCO3 - It can make the exchange membrane exhibit alkaline characteristics, suitable for acidic anion adsorption, water acid-base neutralization, and conventional anion exchange scenarios; halogen anions have strong bonding stability, which can improve the structural stability of the tree exchange membrane; CF3COO - It exhibits extremely high chemical stability, resistance to acids, alkalis, and oxidation. By combining single or multiple anionic groups, the charge density, exchange flux, and environmental compatibility of the exchange membrane can be flexibly controlled.

[0042] For some implementation methods, please refer to Figure 1 The polymer matrix also includes a third repeating unit that connects the first repeating unit and / or the second repeating unit. Figure 1 Part P3), the third repeating unit contains a third aromatic ring group and a second functional group connected in series ( Figure 1 (R1, R2 in the original text). Specifically, the polymer matrix further includes a third linker connecting the first segment and / or the second segment, the third segment comprising a plurality of sequentially linked third repeating units. Optionally, the third aromatic ring group may be the same as or different from the first aromatic ring group or the second aromatic ring group, and the ratio of the number of third repeating units in the third segment may be 1-xy.

[0043] In a specific embodiment, the third repeating unit can adjust the flexibility and steric hindrance of the polymer matrix. By incorporating a third aromatic ring-containing group and a second functional group, the structural limitations of a single chain segment can be avoided, improving flexibility and optimizing the packing density of the polymer matrix. Simultaneously, the third aromatic ring-containing group can enhance the structural compatibility and regularity of the polymer matrix, reducing stress concentration within the chain segment; and piperidine nitroxide radical derivatives can also be bonded to the third aromatic ring-containing group. Optionally, the proportion of the third repeating unit can be less than the proportion of the first and second repeating units.

[0044] In specific embodiments, the second functional group includes one or more of trifluoromethyl, phenyl, alkyl, and trifluoromethylphenyl. The second functional group can be used to regulate the electronic effects and steric hindrance of the third segment. Specifically, the phenyl group possesses a rigid aromatic structure, which can further strengthen the polymer matrix skeleton and improve the temperature and solvent resistance of the exchange membrane; the alkyl group is a flexible saturated carbon chain, which can effectively increase the flexibility of the polymer chain, alleviate the excessive swelling problem of the exchange membrane in an aqueous environment, and optimize the internal ion transport channel structure.

[0045] In a specific embodiment, the polymer matrix adopts a three-segment ordered block copolymer structure, including a first segment, a second segment, and a third segment connected sequentially, i.e., the two ends of the second segment are connected to the first segment and the second segment, respectively. In another embodiment, the third segment can also be connected between the first segment and the second segment to reduce the stress between the first segment and the second segment, improve the overall flexibility of the segments, and allow the performance advantages of the first segment and the second segment to be fully utilized without interference, further improving the overall structural uniformity of the exchange membrane.

[0046] In some embodiments, the mass ratio of the small molecule scavenger is 0.1% to 10% of the polymer matrix mass. Optionally, the mass ratio of the small molecule scavenger is 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the polymer matrix mass.

[0047] In specific embodiments, by controlling the proportion of small molecule scavengers within the above-mentioned range, it is possible to ensure that the anion exchange membrane has sufficient antioxidant, anti-organic pollution, and auxiliary ion exchange activities, giving full play to the functional advantages of free radical modification; at the same time, it can effectively avoid defects such as excessive steric hindrance, decreased membrane regularity, and increased swelling rate that are prone to occur with high content of small molecule scavengers, ensuring the integrity and stability of the polymer matrix structure, so that the exchange membrane can maintain stable ion exchange efficiency and mechanical properties during long-term cyclic use.

[0048] In some embodiments, the number-average molecular weight of the polymer matrix is ​​40,000 g / mol to 80,000 g / mol. Optionally, the number-average molecular weight of the polymer matrix can be 40,000 g / mol, 45,000 g / mol, 50,000 g / mol, 55,000 g / mol, 60,000 g / mol, 65,000 g / mol, 70,000 g / mol, 75,000 g / mol, or 80,000 g / mol.

[0049] In specific embodiments, by controlling the number-average molecular weight of the polymer matrix within the above-mentioned range, the chain segments of the anion exchange membrane can maintain a moderate length and regular structure, taking into account excellent mechanical strength, anti-swelling performance and efficient ion transport capability. This ensures that its skeleton structure is stable and not easily damaged or deformed, while also ensuring unobstructed internal ion channels, fully releasing the ion exchange and antioxidant properties of each functional group, and improving the stability and cycle life of the exchange membrane.

[0050] In some embodiments, the content of nitrogen-containing groups in the polymer matrix is ​​2 mmol / g to 3.0 mmol / g. Optionally, the content of nitrogen-containing groups in the polymer matrix can be 2 mmol / g, 2.1 mmol / g, 2.2 mmol / g, 2.3 mmol / g, 2.4 mmol / g, 2.5 mmol / g, 2.6 mmol / g, 2.7 mmol / g, 2.8 mmol / g, 2.9 mmol / g, or 3.0 mmol / g.

[0051] In specific embodiments, by controlling the content of nitrogen-containing groups within the above-mentioned range, the anion exchange membrane can balance ion exchange activity and structural stability, ensuring both high capacity and high efficiency of anion exchange while maintaining a stable framework and pore structure. This fully matches the modification requirements of small molecule traps, fully releases the ion exchange and antioxidant properties of each functional group, and improves the stability and cycle life of the exchange membrane.

[0052] This invention also provides a method for preparing anion exchange membranes; please refer to [the relevant documentation]. Figure 2 This preparation method is used to prepare the anion exchange membrane as provided in the above embodiments. The preparation method includes: Step S100: Dissolve the polymer matrix and the small molecule scavenger in a solvent to obtain a casting solution; Step S200: The casting solution is coated onto the mold, and after degassing and drying, an intermediate film material is obtained; In step S300, the intermediate membrane material is subjected to ion exchange, washing, and drying to obtain an anion exchange membrane.

[0053] In a specific embodiment, in step S100, the solvent can be a polar aprotic solvent, specifically including but not limited to one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF).

[0054] In a specific embodiment, in step S100, the amount of small molecule scavenger added is based on the mass of the polymer matrix, and the amount of small molecule scavenger added is 0.1% to 10% of the mass of the polymer matrix. Optionally, the amount of small molecule scavenger added can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0055] In a specific embodiment, in step S200, the degassing process needs to be carried out under vacuum, and the vacuum degree can be -0.08MPa to -0.1MPa; optionally, the vacuum degree can be -0.08MPa, -0.09MPa, or -0.1MPa. The degassing time is 10min to 30min; optionally, the degassing time can be 10min, 15min, 20min, 25min, or 30min.

[0056] In a specific embodiment, in step S200, the drying process employs a gradient temperature increase to allow the solvent to fully evaporate. The gradient temperature increase range can be 60℃~120℃. The drying time is 6h~24h; optionally, the drying time can be 6h, 8h, 12h, 15h, 20h, 22h, or 24h.

[0057] In a specific embodiment, in step S300, the ion exchange process employs an alkaline solution treatment to convert the anion exchange membrane into a hydroxide form. Optionally, the alkaline solution treatment environment may include potassium hydroxide, sodium hydroxide, hydrogen peroxide, etc.

[0058] In a specific embodiment, in step S300, the concentration of the alkali solution for ion exchange is 1 mol / L to 5 mol / L; optionally, the alkali concentration can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L. The temperature for ion exchange is 25℃ to 60℃; optionally, the temperature can be 25℃, 30℃, 40℃, 50℃, or 60℃. The duration of ion exchange can be 12h to 24h; optionally, the duration can be 12h, 15h, 20h, 22h, or 24h.

[0059] In a specific embodiment, in step S300, the drying temperature can be 60℃~80℃; optionally, the drying temperature can be 60℃, 65℃, 70℃, 75℃, or 80℃. The drying time can be 4h~8h; optionally, the drying time can be 4h, 5h, 6h, 7h, or 8h.

[0060] The preparation method provided by this invention can be used to prepare the anion exchange membranes provided in the above embodiments. This method is simple, cost-controllable, and directly adaptable to existing industrial AEM production equipment. By using a polar aprotic solvent to simultaneously dissolve and blend the polymer matrix and small molecule scavenging agent, no additional surface modification is required, ensuring uniform mixing and solving the problem of poor compatibility in existing blending techniques. Simultaneously, by employing vacuum gradient heating for film formation, the slow evaporation of the solvent can be controlled, ensuring membrane density and quality, and avoiding membrane defects caused by excessively rapid solvent evaporation.

[0061] The technical solution of the present invention will be described in detail below through specific embodiments.

[0062] Example 1 This embodiment provides an anion exchange membrane, including a polymer matrix and a small molecule scavenger. The polymer matrix contains a terphenyl-piperidine copolymer polyarylpiperidine resin, and the small molecule scavenger contains 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (4-hydroxy-TEMPO).

[0063] The polymer matrix has a number average molecular weight of 50,000 g / mol, the content of nitrogen-containing groups in the polymer matrix is ​​2.5 mmol / g, and the mass percentage of the small molecule scavenger relative to the polymer matrix is ​​0.1%.

[0064] The preparation method of this anion exchange resin includes: (1) Add 100g of polymer matrix and 0.1g of small molecule scavenger to 500mL of DMSO solvent and stir at room temperature (25℃) for 24h (stirring rate 300r / min) until completely dissolved to obtain a uniform and transparent casting solution. (2) The casting solution was coated on a polytetrafluoroethylene plate with a coating thickness of 500 μm. After degassing in a vacuum oven at 60°C for 30 min (vacuum degree -0.09 MPa), the temperature was increased to 120°C at a rate of 10°C / h and kept at the temperature for 6 h to evaporate the solvent and form a film. (3) After the membrane material is cooled to room temperature, the membrane is peeled off, soaked in 1 mol / L KOH solution at 25°C for 12 h, rinsed with deionized water until neutral, and dried in an oven at 60°C for 8 h to obtain an anion exchange membrane.

[0065] Example 2 This embodiment provides an anion exchange membrane, including a polymer matrix and a small molecule scavenger. The polymer matrix contains a terphenyl-piperidine copolymer polyarylpiperidine resin, and the small molecule scavenger contains 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (4-hydroxy-TEMPO).

[0066] The polymer matrix has a number average molecular weight of 50,000 g / mol, the nitrogen-containing group content in the polymer matrix is ​​2.5 mmol / g, and the small molecule scavenger accounts for 2.5% of the mass of the polymer matrix.

[0067] The preparation method of this anion exchange resin includes: (1) Add 100g of polymer matrix and 2.5g of small molecule scavenger to 500mL of DMSO solvent, stir at 50℃ for 18h (stirring rate 350r / min) until completely dissolved to obtain a uniform and transparent casting solution. (2) The casting solution was coated onto a glass slide with a coating thickness of 120 μm. After degassing in a vacuum oven at 80 °C for 20 min (vacuum degree -0.09 MPa), the temperature was increased to 120 °C at a rate of 8 °C / h and kept at that temperature for 15 h to evaporate the solvent and form a film. (3) After the membrane material is cooled to room temperature, peel off the membrane, soak it in 1 mol / L KOH solution at 40°C for 18 hours, rinse it with deionized water until neutral, and dry it in an oven at 70°C for 6 hours to obtain an anion exchange membrane.

[0068] Example 3 This embodiment provides an anion exchange membrane, including a polymer matrix and a small molecule scavenger. The polymer matrix contains a terphenyl-piperidine copolymer polyarylpiperidine resin, and the small molecule scavenger contains 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (4-hydroxy-TEMPO).

[0069] The polymer matrix has a number average molecular weight of 50,000 g / mol, the content of nitrogen-containing groups in the polymer matrix is ​​2.5 mmol / g, and the mass percentage of the small molecule scavenger relative to the polymer matrix is ​​5%.

[0070] The preparation method of this anion exchange resin includes: (1) Add 100g of polymer matrix and 5g of small molecule scavenger to 550mL of DMSO solvent and stir at room temperature (25℃) for 20h (stirring rate 300r / min) until completely dissolved to obtain a uniform and transparent casting solution. (2) The casting solution was coated on a polytetrafluoroethylene plate with a coating thickness of 120 μm. After degassing in a vacuum oven at 100 °C for 20 min (vacuum degree -0.09 MPa), the temperature was increased to 120 °C at a rate of 5 °C / h and kept at the temperature for 24 h to evaporate the solvent and form a film. (3) After the membrane material is cooled to room temperature, the membrane is peeled off, soaked in 1 mol / L KOH solution at 60°C for 24 hours, rinsed with deionized water until neutral, and dried in an oven at 80°C for 4 hours to obtain an anion exchange membrane.

[0071] Example 4 This embodiment provides an anion exchange membrane, including a polymer matrix and a small molecule scavenger. The polymer matrix contains a terphenyl-piperidine copolymer polyarylpiperidine resin, and the small molecule scavenger contains 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (4-hydroxy-TEMPO).

[0072] The polymer matrix has a number average molecular weight of 50,000 g / mol, the content of nitrogen-containing groups in the polymer matrix is ​​2.5 mmol / g, and the mass percentage of the small molecule scavenger relative to the polymer matrix is ​​15%.

[0073] The preparation method of this anion exchange resin includes: (1) Add 100g of polymer matrix and 15g of small molecule scavenger to 550mL of DMSO solvent and stir at room temperature (25℃) for 20h (stirring rate 300r / min) until completely dissolved to obtain a uniform and transparent casting solution. (2) The casting solution was coated on a polytetrafluoroethylene plate with a coating thickness of 120 μm. After degassing in a vacuum oven at 100 °C for 20 min (vacuum degree -0.09 MPa), the temperature was increased to 120 °C at a rate of 5 °C / h and kept at the temperature for 24 h to evaporate the solvent and form a film. (3) After the membrane material is cooled to room temperature, the membrane is peeled off, soaked in 1 mol / L KOH solution at 60°C for 24 hours, rinsed with deionized water until neutral, and dried in an oven at 80°C for 4 hours to obtain an anion exchange membrane.

[0074] Comparative Example 1 This comparative example provides an anion exchange resin. The difference between this comparative example and Example 1 is that no small molecule scavenging agent is added.

[0075] Comparative Example 2 This comparative example provides an anion exchange membrane comprising a polymer matrix and an inorganic inhibitor. The polymer matrix contains a terphenyl-piperidine copolymer polyarylpiperidine resin, and the inorganic inhibitor contains CeO2 nanoparticles (particle size 20 nm).

[0076] The number average molecular weight of the polymer matrix is ​​50,000 g / mol, and the content of nitrogen-containing groups in the polymer matrix is ​​2.5 mmol / g, which is 2.5% of the mass of the polymer matrix.

[0077] The preparation method of this anion exchange resin includes: (1) Add 100g of polymer matrix to 600mL of DMSO solvent, dissolve it completely, add 2.5g of inorganic additive, ultrasonically disperse at room temperature (25℃) for 30min, and then stir for 18h (stirring rate 300r / min) to obtain casting solution; (2) The casting solution was coated on a polytetrafluoroethylene plate with a coating thickness of 120 μm. After degassing in a vacuum oven at 100 °C for 20 min (vacuum degree -0.09 MPa), the temperature was increased to 120 °C at a rate of 5 °C / h and kept at the temperature for 24 h to evaporate the solvent and form a film. (3) After the membrane material is cooled to room temperature, the membrane is peeled off, soaked in 1 mol / L KOH solution at 60°C for 24 hours, rinsed with deionized water until neutral, and dried in an oven at 80°C for 4 hours to obtain an anion exchange membrane.

[0078] The anion exchange membranes provided in Examples 1-4 and Comparative Examples 1-2 were subjected to the following tests: (1) Ion exchange capacity (IEC): The titration method is used to test the IEC. The sample is immersed in 0.1 mol / L HCl solution. After the reaction is complete, the remaining HCl is titrated with 0.1 mol / L NaOH solution. The IEC is calculated in mmol / g. (2) Hydroxide conductivity: The AC impedance method was used for testing. The test temperature was 80℃ and the test environment was a membrane sample soaked in deionized water. The unit is mS / cm. (3) Anti-free radical aging performance: The membrane sample was immersed in a simulated alkaline electrolytic aging solution containing 1 mol / L KOH and 10 mmol / L H2O2 and immersed at 80℃ for 100 h. The conductivity retention rate of the membrane before and after aging was tested (conductivity after aging / conductivity before aging × 100%). The higher the retention rate, the better the anti-free radical aging performance. (4) Alkali stability: The membrane sample was immersed in 3 mol / L KOH solution and kept at 80℃ for 200 h. The IEC retention rate of the membrane before and after immersion was tested (IEC after immersion / IEC before immersion × 100%). The higher the retention rate, the better the alkali stability. (5) Mechanical properties: The tensile strength (unit: MPa) and elongation at break (unit: %) of the membrane were tested using a universal testing machine at a tensile rate of 50 mm / min.

[0079] The test results are shown in Table 1: Table 1

[0080] As can be seen from the test results of the examples and comparative examples in Table 1, the use of a mixture of polymer matrix and small molecule scavenger exhibits excellent compatibility, achieving uniform molecular-level dispersion and a dense, defect-free membrane material. Compared to anion exchange membranes prepared with ordinary polymer matrices in existing technologies, this method significantly improves the mechanical properties of the membrane material while ensuring electrical performance. Furthermore, compared to existing inorganic inhibitors, the membrane material exhibits a better appearance and better compatibility. Moreover, by controlling the addition amount of small molecule scavenger within the range of 0.1% to 10%, a synergistic improvement in membrane anti-aging properties, alkali stability, ion conduction, and mechanical properties can be achieved.

[0081] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship of the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0082] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. An anion exchange membrane, characterized in that, The invention comprises a mixed polymer matrix and a small molecule scavenger, wherein the polymer matrix contains linked aromatic ring groups and nitrogen-containing groups, the nitrogen-containing groups including piperidine groups and / or quinine groups, and the small molecule scavenger contains piperidine nitroxide radical derivatives.

2. The anion exchange membrane according to claim 1, characterized in that, The polymer matrix comprises a first repeating unit and a second repeating unit connected in series. The first repeating unit comprises a first aromatic ring group and the piperidine group connected in series. The second repeating unit comprises a second aromatic ring group and the quinine group connected in series.

3. The anion exchange membrane according to claim 2, characterized in that, The polymer matrix further comprises a first functional group, which is attached to the piperidine group and / or the quinine group.

4. The anion exchange membrane according to claim 3, characterized in that, The polymer matrix further includes anionic groups, and both the first repeating unit and the second repeating unit are connected to the anionic groups.

5. The anion exchange membrane according to claim 4, characterized in that, The first functional group includes one or more of hydrogen, alkyl, alkenyl, or alkynyl; and / or, the anionic group includes OH. - Cl - ,Br - HCO3 - NO3 - CF3COO - or CH3COO - One or more of them.

6. The anion exchange membrane according to claim 5, characterized in that, The polymer matrix further includes a third repeating unit connecting the first repeating unit and / or the second repeating unit, the third repeating unit comprising a third aromatic ring group and a second functional group connected together.

7. The anion exchange membrane according to claim 1, characterized in that, The aromatic ring group includes one or more of biphenyl, p-terphenyl, m-terphenyl, diphenylmethane, 1,3,5-triphenylbenzene, triphenylmethane, tris(ethylene), 9,9-dimethylfluorene, and 9,9-spirodifluorene; and / or The piperidine nitric oxide radical derivatives include one or more of the following: 2,2,6,6-tetramethylpiperidine-1-ox radical, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-ox radical, 4-(2-bromoethoxy)-2,2,6,6-tetramethylpiperidine-1-ox radical, 4-(3-bromopropoxy)-2,2,6,6-tetramethylpiperidine-1-ox radical, and 4-chloromethyl-2,2,6,6-tetramethylpiperidine-1-ox radical.

8. The anion exchange membrane according to claim 1, characterized in that, The mass ratio of the small molecule scavenger is 0.1% to 10% of the polymer matrix; and / or The number-average molecular weight of the polymer matrix is ​​40,000 g / mol to 80,000 g / mol; and / or The nitrogen-containing group has a content of 2 mmol / g to 3.0 mmol / g in the polymer matrix.

9. A method for preparing an anion exchange membrane, characterized in that, The method for preparing the anion exchange membrane according to any one of claims 1-8 comprises: The polymer matrix and small molecule scavenger are dissolved in a solvent to obtain a casting solution; The casting solution is coated onto a mold, and after degassing and drying, an intermediate film material is obtained. The intermediate membrane material is subjected to ion exchange, washing, and drying to obtain an anion exchange membrane.

10. The preparation method according to claim 9, characterized in that, The vacuum degree of degassing is -0.08MPa to -0.1MPa, and the degassing time is 10min to 30min; the drying adopts a gradient temperature increase of 60℃ to 120℃, and the drying time is 6h to 24h.

11. The preparation method according to claim 9, characterized in that, The concentration of the alkaline solution for the ion exchange is 1 mol / L to 5 mol / L, the temperature for the ion exchange is 25℃ to 60℃, and the duration of the ion exchange is 12h to 24h.

12. The anion exchange membrane according to any one of claims 1-8, characterized in that, The anion exchange membrane is used in alkaline water electrolysis for hydrogen production or in fuel cells.

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