An anion exchange membrane electrode, its preparation method and application

Abstract

This invention discloses an anion exchange membrane electrode, its preparation method, and its application, belonging to the field of new energy materials and catalytic electrode preparation technology. The method includes: S1. Preparing an anode catalyst slurry comprising a hydrophobic covalent organic framework material, an anode catalyst, an anion exchange ionomer, and a solvent; S2. Preparing a cathode catalyst slurry comprising a cathode catalyst, anion exchange ionomer, and a solvent; S3. Spraying or coating the anode catalyst slurry and cathode catalyst slurry onto both sides of the anion exchange membrane or gas diffusion layer, respectively, and obtaining the anion exchange membrane electrode after heat treatment. This invention can solve the problems of high gas-liquid-ion three-phase mass transfer resistance, easy obscuring of active catalytic sites by ionomers, and water management imbalance in existing AEMWE devices.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials and catalytic electrode preparation technology, specifically relating to an anion exchange membrane electrode and its preparation method and application. Background Technology

[0002] Electrolysis of water for hydrogen production has become a promising green hydrogen production route due to its low carbon emissions, few byproducts, and high hydrogen purity. Currently, mainstream electrolysis technologies include alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), solid oxide electrolyzer (SOEC), and anion exchange membrane water electrolysis (AEMWE). Among these, AEMWE technology combines the low cost of AWE with the high energy efficiency and dynamic response characteristics of PEMWE, making it an important direction for future green hydrogen production.

[0003] The membrane electrode assembly (MEA) is the core component determining the electrolysis efficiency of AEMWE technology. The MEA consists of an anion exchange membrane (AEM) and two anode and cathode catalyst layers on either side. The catalyst layer is the core region of the reaction; the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) occur in the anode and cathode catalyst layers, respectively, and are typically composed of catalyst powder and ionomers. The ionomers not only act as binders to fix the catalyst particles but also construct gas-liquid-ion mass transfer channels, promoting the migration of hydroxide ions and the effective formation of the reaction interface. Currently, the preparation of AEMWE MEAs typically uses ionomers with similar structures to AEMs to improve the compatibility between the catalyst layer and the membrane and reduce interfacial resistance. However, this method has certain limitations in practical applications. First, the design of anion exchange membranes emphasizes gas barrier performance, but the corresponding ionomers tend to form a dense coating layer on the surface of the catalyst particles, hindering gas diffusion and product gas release, leading to the masking of active sites and reduced reaction efficiency. Second, existing ionomer systems struggle to control the local hydration environment of the catalyst layer. In conventional anolyte supply mode, flooding often occurs at the anode, while the cathode may experience insufficient water or localized drying, leading to an imbalance in water management. In particular, the inability to optimize water management for anodes and cathodes using the same ionomer system according to their different electrode requirements limits the improvement of membrane electrode performance. These problems are especially pronounced in the anolyte oxygen evolution reaction at high current densities.

[0004] To address the issue of poor compatibility between AEM membranes and catalysts / ionomers, researchers have developed various novel anion exchange membranes or ionomers. For example, Chinese patent document CN120842640A discloses an anion exchange membrane and membrane electrode preparation method based on isopropylpiperidone and biphenyl, and Chinese patent document CN115093559A discloses a self-polymerizing microporous ionomer, its preparation method, and its application. However, these methods suffer from high synthesis costs and difficulty in scaling up production.

[0005] In summary, limited mass transfer in the catalyst layer and imbalanced water management are key bottlenecks in improving the performance of AEMWE, affecting electrolysis efficiency and the sustainable operation of the equipment. Against this backdrop, there is an urgent need to introduce novel functional materials to construct membrane electrodes with tunable microstructures and synergistic mass transfer properties, thereby achieving synergistic optimization of mass transfer and water management at the microscopic level. Summary of the Invention

[0006] This invention addresses the problems of high gas-liquid-ion three-phase mass transfer resistance, easy obscuring of active catalytic sites by ionomers, and water management imbalance in existing AEMWE devices. It provides an anion exchange membrane electrode and its preparation method. By introducing a functional covalent organic framework (COF) material with regular pore structure and hydrophobic properties into the anode catalyst layer, a continuous gas dissipation and water management channel is constructed, and the hydration layer distribution of the anode catalyst layer is regulated. This reduces the energy barrier for oxygen desorption, reduces gas retention, and promotes efficient oxygen desorption, thereby significantly improving the electrolysis performance and operational stability of the AEMWE device.

[0007] The specific technical solution adopted is as follows: A method for preparing an anion exchange membrane electrode includes the following steps: S1. An anode catalyst slurry comprising a hydrophobic covalent organic framework material, an anode catalyst, an anion exchange ionomer, and a solvent; wherein the hydrophobic covalent organic framework material is selected from at least one of β-keto-enamine COF with fluorine-substituted aromatic structural units, benzotriazolyl β-keto-enamine COF with alkyl side chain modification, and carbon-carbon double bond linked COF; S2. Prepare a cathode catalyst slurry comprising a cathode catalyst, anion exchange polymer, and a solvent; S3. The anode catalyst slurry and cathode catalyst slurry are sprayed or coated onto both sides of the anion exchange membrane or gas diffusion layer, respectively, and after heat treatment, an anion exchange membrane electrode is obtained.

[0008] The anion exchange membrane electrode proposed in this invention incorporates a hydrophobic covalent organic framework (COF) in its anode catalyst layer. This COF possesses a regular pore structure and hydrophobic properties, significantly optimizing gas mass transfer and hydration management capabilities. Simultaneously, it effectively reduces the retention of reactant gases and the accumulation of hydration layers, promoting oxygen desorption and gas dispersion, thereby significantly improving electrolysis performance and catalytic reaction efficiency. Furthermore, ion conductivity is also enhanced, further optimizing ion migration during the reaction process and strengthening overall electrolysis efficiency.

[0009] Preferably, the hydrophobic covalent organic framework material has a particle size of 1-10 μm and a pore size of 1-5 nm.

[0010] Furthermore, the β-keto-enamine type COF containing fluorine-substituted aromatic structural units can specifically be COF-TpPa-CF3. The preparation method is as follows: using 1,3,5-tricarboxymethyl phloroglucinol and trifluoromethyl-substituted aromatic diamine as raw materials, dispersing them in a solvent, adding an acidic catalyst, and carrying out a solvothermal reaction to obtain the β-keto-enamine type COF containing fluorine-substituted aromatic structural units.

[0011] Furthermore, the alkyl-side-chain modified benzotriazole β-keto-enamine COF can specifically be COF-TzDa-octyl, which is prepared by using alkylated 2,5-dihydroxyterephthalaldehyde and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine as raw materials, dispersing them in a solvent, adding an acidic catalyst, condensing them and then carrying out a solvothermal reaction to obtain the alkyl-side-chain modified benzotriazole β-keto-enamine COF.

[0012] Specifically, the anode catalyst is a non-precious metal catalyst or a precious metal catalyst; the non-precious metal catalyst includes at least one metal selected from nickel, iron, cobalt, and manganese, or at least one of their alloys, oxides, hydroxides, spinel, or perovskite structure materials; the precious metal catalyst includes at least one metal selected from iridium and ruthenium, or at least one of their alloys or oxides.

[0013] Preferably, the mass ratio of the hydrophobic covalent organic framework material, the anode catalyst, and the anion exchange ionomer is 1:15-50:0.3-3; the anode catalyst is a nickel-molybdenum alloy, a nickel-iron alloy, a nickel-iron oxide hydroxyl compound, a nickel-iron layered double hydroxide, a nickel-iron oxide, a nickel-cobalt spinel oxide, cobalt tetroxide, a nickel-manganese oxide, a lanthanum-nickel oxide, a barium-strontium-cobalt-iron oxide, iridium oxide, iridium black, or an iridium-ruthenium alloy oxide.

[0014] Specifically, the cathode catalyst is a non-precious metal catalyst or a precious metal catalyst; the non-precious metal catalyst includes at least one metal selected from nickel, cobalt, and iron, or at least one of their alloys, oxides, hydroxides, or carbon-supported complexes; the precious metal catalyst includes at least one metal selected from platinum, palladium, and rhodium, or at least one of their alloys or oxides.

[0015] Preferably, the cathode catalyst is nickel, nickel-iron alloy, nickel-cobalt alloy, nickel-molybdenum alloy, cobalt-iron alloy, cobalt tetroxide, iron oxide, nickel-iron oxide, nickel-iron hydroxide, platinum-carbon, platinum-rhodium-carbon, platinum black, or palladium.

[0016] Specifically, the anion exchange polymer is PiperION. TM Sustainion TM Fumasep TM Aemion TM At least one of the series of anion exchange polymers.

[0017] Preferably, in steps S1 and S2, the solvent is a mixture of an organic solvent and water. The organic solvent is at least one of tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, isopropanol, and dichloromethane. The volume ratio of the organic solvent to water is 1:4 to 4:1.

[0018] Preferably, the solid content of the anode catalyst slurry is 0.5-10 wt%, and the solid content of the cathode catalyst slurry is 0.1-8 wt%.

[0019] Furthermore, in step S3, the slurry is sprayed or coated using either catalyst coating membrane (CCM) technology or catalyst coating substrate (CCS) technology; when using catalyst coating membrane (CCM) technology, the loading of the anolyte catalyst layer on the anion exchange membrane surface is 0.1-5.0 mg•cm. -2 The loading of the cathode catalyst layer on the surface of the anion exchange membrane was 0.1-5.0 mg•cm. -2 When using catalyst coating substrate (CCS) technology, the loading of the anolyte catalyst layer on the gas diffusion layer surface is 0.5-4.0 mg•cm. -2 The loading of the cathode catalyst layer on the surface of the gas diffusion layer is 0.5-4.0 mg•cm. -2 .

[0020] Furthermore, in step S3, the heat treatment temperature is 40-110℃ and the time is 1-12 hours.

[0021] The present invention also provides an anion exchange membrane electrode prepared by the method described above.

[0022] The present invention also provides the application of the anion exchange membrane electrode in water electrolysis for hydrogen production.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Improved gas mass transfer performance: The present invention introduces hydrophobic covalent organic framework material into the anode catalyst layer. The hydrophobic covalent organic framework material significantly improves the gas dissipation capacity of the anode catalyst layer through its regular one-dimensional channel structure and hydrophobic properties. By reducing gas retention and improving oxygen desorption efficiency, it effectively avoids bubble accumulation and blockage, keeps the gas-liquid-ion three-phase reaction interface unobstructed, and thus improves the overall reaction efficiency.

[0024] (2) Optimization of gas-liquid mass transfer and water management: This invention introduces a hydrophobic covalent organic framework material into the anode catalyst layer. The unique structure of the hydrophobic covalent organic framework material not only reduces the retention of liquid water, but also effectively regulates the distribution of the hydration layer. By reducing the interference of the hydration layer, oxygen can be smoothly desorbed and quickly discharged, avoiding the accumulation of hydration layer and flooding, thereby maintaining stable hydration conditions on the anode side and optimizing electrolysis performance.

[0025] (3) Improved exposure of active sites: The introduction of hydrophobic covalent organic framework material makes the surface of the anode catalyst layer uniformly modified. Its pore structure reduces the coating of ionomers on the catalyst surface, reduces the shielding of active sites, and combined with the improvement of gas dissipation performance, further improves the electrochemical active area of ​​the anode catalyst layer and optimizes the three-phase reaction interface of oxygen evolution reaction.

[0026] (4) Good process compatibility and application prospects: The anion exchange membrane electrode preparation method of the present invention has simple steps and mild conditions. It is well compatible with the current mainstream anode catalyst coated membrane or catalyst coated substrate membrane electrode preparation process, and has the feasibility of scale-up preparation and large-scale application. In particular, it has broad application prospects in high-efficiency and long-life AEMWE system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the chemical structure of the β-keto-enamine COF (COF-TpPa-CF3) with fluorine-substituted aromatic structural units used in Example 1.

[0028] Figure 2 The image is a scanning electron microscope image obtained by fully dispersing the β-keto-enamine COF (COF-TpPa-CF3) powder containing fluorine-substituted aromatic structural units used in Example 1 in an isopropanol-water (4:1) mixed solvent, coating it onto the surface of a silicon wafer, and then drying it.

[0029] Figure 3 This is a scanning electron microscope image of the surface of the anode catalyst layer obtained in Example 1.

[0030] Figure 4 This is a scanning electron microscope image of the surface of the anode catalyst layer obtained in Example 2.

[0031] Figure 5 This is a scanning electron microscope image of the surface of the anode catalyst layer obtained in Example 3.

[0032] Figure 6 This is a scanning electron microscope image of the surface of the anode catalyst layer obtained in Comparative Example 1.

[0033] Figure 7The current-voltage (IV) polarization curves of the membrane electrodes prepared in Examples 1-3 and the comparative examples are shown. Detailed Implementation

[0034] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.

[0035] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0036] Example 1 COF-TpPa-CF3 can be synthesized according to the methods described in the literature or by the following method: 1,3,5-tricarboxymethyl phloroglucinol and 2,5-diaminotrifluorotoluene are added in a certain proportion to a mixed solvent of mesitylene and 1,4-dioxane, allowing them to be fully dispersed or dissolved. Then, 6 mol / L aqueous acetic acid solution is added as a catalyst, and the reaction is carried out under closed conditions at 120 °C for 72 hours as a solvothermal reaction. After the reaction, the system is naturally cooled to room temperature, the reaction vessel is opened, the solid precipitate is collected by filtration, and washed repeatedly with acetone, tetrahydrofuran, and methanol to remove unreacted monomers and residual solvent. Finally, it is dried at 100 °C for 24 hours to obtain a β-keto-enamine COF (COF-TpPa-CF3) containing a fluorinated substituted aromatic structural unit.

[0037] Preparation of the anode catalyst slurry: Accurately weigh 15 mg of IrO2 powder and 56.25 mg of PiperION A5-HCO3 ionomer solution (methanol type) (solution solid content is 5 wt%, actual ionomer mass is 2.82 mg), and place them in a sample bottle. Then add 0.94 mg of COF-TpPa-CF3 powder. The COF-TpPa-CF3 powder has a particle size of 1-8 μm and a pore size range of 1.5-5 nm, ensuring that the mass ratio of PiperION A5-HCO3 anion exchange ionomer to TpPa-CF3 is 3:1. Finally, add 0.60 mL of isopropanol / deionized water mixed solvent (volume ratio of isopropanol to deionized water is 4:1), and ultrasonically disperse the mixture in an ultrasonic instrument for 1.5 hours to obtain a uniform and stable anode catalyst slurry.

[0038] Preparation of cathode catalyst slurry: Accurately weigh 10 mg of 60 wt% platinum content Pt / C catalyst and 50.1 mg of PiperION A5-HCO3 ionomer solution (methanol type) (solution solid content is 5 wt%, actual ionomer mass is 2.505 mg), place them in a sample bottle, and then add 1.50 mL of isopropanol / deionized water mixed solvent (isopropanol and deionized water volume ratio is 4:1), and ultrasonically disperse for 1.5 hours to obtain cathode catalyst slurry.

[0039] Preparation of anion exchange membrane electrodes: Using catalyst-coated membrane (CCM) technology, the above-mentioned anolyte catalyst slurry and cathode catalyst slurry were respectively sprayed onto both sides of the PiperION A40 anion exchange membrane, ensuring that the loading of the cathode catalyst layer on the surface of the anion exchange membrane was 2.5 mg·cm³. -2 The loading of the anolyte catalyst layer on the surface of the anion exchange membrane is 3.75 mg·cm³. -2 The electrode was then dried in a vacuum oven at 40°C for 12 hours to obtain anion exchange membrane electrode.

[0040] Example 2 COF-TzDa-octyl can be synthesized according to the methods described in the literature or by the following method: First, 2,5-dihydroxyterephthalaldehyde (Da) is modified by nucleophilic substitution to obtain the octyl-substituted dialdehyde monomer Da-octyl. Then, Da-octyl and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine are added in a certain proportion to a mixed solvent of toluene and 1,4-dioxane to ensure complete dispersion or dissolution. Subsequently, 3 mol / L aqueous acetic acid solution is added as a catalyst, and condensation is carried out under acidic conditions. The reaction is then carried out under closed conditions at 120°C for 72 hours in a solvothermal environment. After the reaction was completed, the system was naturally cooled to room temperature. The reaction vessel was opened, the solid precipitate was collected by filtration, and washed repeatedly with acetone, tetrahydrofuran and methanol to remove unreacted monomers and residual solvents. Finally, it was dried at 100 °C for 24 hours to obtain alkyl side chain modified benzotriazolyl β-keto-enamine COF (COF-TzDa-octyl).

[0041] Preparation of the anode catalyst slurry: Accurately weigh 20 mg of NiFe catalyst and 56.25 mg of Sustainion X37-60 ionomer solution (solution solid content 5 wt%, actual ionomer mass 2.82 mg), and place them in a sample vial. Then add 2.13 mg of COF-TzDa-octyl powder, with a particle size of approximately 5 μm and a pore size of approximately 5 nm, ensuring that the mass ratio of Sustainion X37-60 anion exchange ionomer to TzDa-octyl is 1.3:1. Finally, add 3.20 mL of isopropanol / deionized water mixed solvent (volume ratio of isopropanol to deionized water 4:1), and ultrasonically disperse the mixture in an ultrasonic instrument for 1.5 hours to obtain a uniform and stable anode catalyst slurry.

[0042] Preparation of cathode catalyst slurry: Accurately weigh 15 mg of NiMo powder and 50.00 mg of Sustainion X37-60 ionomer solution (solid content of solution is 5 wt%, actual ionomer mass is 2.5 mg), place them in a sample bottle, and then add 3.00 mL of isopropanol / deionized water mixed solvent (volume ratio of isopropanol and deionized water is 2:1), and ultrasonically disperse for 2.0 hours to obtain cathode catalyst slurry.

[0043] Preparation of anion exchange membrane electrode: Using catalyst coating substrate (CCS) technology, the above-mentioned anode catalyst slurry and cathode catalyst slurry were respectively sprayed onto both sides of the gas diffusion layer, ensuring that the loading of the anode catalyst layer on the surface of the anode gas diffusion layer was 3.5 mg·cm³. -2 The loading of the cathode catalyst layer on the cathode gas diffusion layer is 3.75 mg·cm³.-2 After being pressed with a Sustainion X37-60 anion exchange membrane to form a sandwich structure of a cathode gas diffusion layer supported on a cathode catalyst, an anion exchange membrane, and an anode gas diffusion layer supported on anode catalyst, the membrane was dried in a vacuum oven at 40°C for 12 hours to obtain an anion exchange membrane electrode.

[0044] Example 3 In this embodiment, when preparing the anode catalyst slurry, the 2.13 mg COF-TzDa-octyl in Example 2 was replaced with an equal amount of COF-TpPa-CF3 powder, and the COF-TpPa-CF3 powder had a particle size of 1-8 μm and a pore size range of 1.5-5 nm. The other raw material types, amounts, and operating steps were the same as in Example 2, and an anion exchange membrane electrode was prepared.

[0045] Comparative Example 1 In this comparative example, no hydrophobic covalent organic framework material (COF) was added when preparing the anode catalyst slurry. The other raw material types, amounts, and operating steps were the same as in Example 1, and an anion exchange membrane electrode was prepared.

[0046] Sample Analysis The anion exchange membrane electrodes prepared in Examples 1-3 and Comparative Example 1 were characterized and their performance was tested.

[0047] Figure 1 The diagram shows the chemical structure of COF-TpPa-CF3 in Example 1. As can be seen, it possesses both a regular one-dimensional pore structure and hydrophobic trifluoromethyl functional groups distributed on the pore wall surface at the molecular level. The synergistic effect between the regular one-dimensional pore structure and the hydrophobic properties helps to form efficient gas dissipation channels and hydration layer regulation channels inside the anode catalyst layer, thereby achieving synergistic optimization of the oxygen desorption process and local hydration management.

[0048] Figure 2 The image shows a scanning electron microscope (SEM) image of COF-TpPa-CF3 powder after it has been fully dispersed in an isopropanol-water (4:1) mixed solvent, coated onto a silicon wafer, and dried. The image demonstrates that COF-TpPa-CF3 is well dispersed in the mixed solvent system (isopropanol-water, volume ratio 4:1), exhibiting good dispersion stability.

[0049] like Figure 3-5 As shown, the anode catalyst layer prepared in Examples 1-3 has a uniform surface structure, and a continuous and uniformly distributed composite catalyst layer is formed between the COF material, catalyst particles and anion exchange polymer.

[0050] like Figure 6As shown in Comparative Example 1, the anion exchange ionomer formed an excessively dense coating layer on the catalyst surface, significantly hindering gas-liquid mass transfer. Due to the hydrophilicity of the ionomer, a thick hydrated layer formed on the catalyst surface, affecting oxygen desorption efficiency and gas dissipation. Hydration hinders effective water desorption, further exacerbating the accumulation of the hydrated layer, inhibiting reaction efficiency, and reducing the stability of the catalyst layer.

[0051] like Figure 7 As shown in the current-voltage (IV) polarization curves, under test conditions of 1 M KOH anode single-sided supply and operating temperature of 80 °C, the anion exchange membrane electrodes of the examples and the comparative examples exhibit significant differences under the same current density. Under the same current density, the voltage of Examples 1-3, which introduced hydrophobic covalent organic framework materials, was significantly lower than that of Comparative Example 1, which did not introduce COF materials, indicating that the introduction of hydrophobic covalent organic frameworks can effectively reduce polarization losses during electrolysis. Although the hydrophobic covalent organic framework material introduced in Example 2 is similar in chemical structure to that of Examples 1 and 3, it has a block structure. This morphology makes it difficult for the material to be uniformly distributed and stably embedded in the catalyst layer, limiting its advantages in mass transfer regulation. In contrast, the COF-TpPa-CF3 material in Examples 1 and 3 has better dispersibility and can be more uniformly embedded in the catalyst layer, thereby more effectively optimizing the reaction interface and improving the overall electrolysis performance.

[0052] It is worth noting that, compared with Comparative Example 1, Examples 1-3 exhibit a more significant voltage advantage in the high current density range. This indicates that the strategy of introducing hydrophobic covalent organic framework materials to regulate the microstructure of the catalyst layer in this invention has a more prominent synergistic optimization effect on the mass transfer process and water management process under high current density operating conditions.

[0053] The prepared membrane electrode was assembled into an anion exchange membrane water electrolysis cell for electrochemical performance testing. During the test, electrolyte solution was continuously introduced into the anode side at a flow rate controlled at 30 mL / min. -1 The polarization curve of the electrolyzer was tested under isothermal conditions. The electrolysis performance was evaluated by gradually changing the current density and recording the corresponding cell voltage. The anolyte flow rate was 30 mL / min. -1 The current density is 0.1-6 A cm⁻¹ -2 The current density is 0.1-1 Acm. -2 For every change of 0.1A cm -2 Record the corresponding scan voltage; current density is 1-6 A cm⁻¹ -2 For every 0.2 A cm⁻² change, the corresponding scan voltage is recorded once.

[0054] Under the above test conditions, the current density is 2.0 A·cm. -2 The operating range of 80% and above is defined as the high current density operating range. A comparison of the embodiments and comparative examples shows that the membrane electrode of the embodiments exhibits significantly improved water electrolysis performance in the high current density range, with reduced operating voltage or increased current output capability, resulting in an overall performance improvement of approximately 8%–40%.

[0055] In summary, this invention, by introducing a hydrophobic covalent organic framework material into the anodic catalyst layer of the anion exchange membrane electrode, effectively constructs a multi-scale synergistic microstructure combining regular one-dimensional channels and hydrophobic functional groups without altering existing membrane electrode fabrication processes. This significantly improves the gas-liquid mass transfer and water distribution behavior within the catalyst layer. Compared to the comparative example, the embodiment exhibits a lower polarization voltage under the same operating conditions and demonstrates more significant performance advantages in the high current density range. This fully verifies that the proposed hydrophobic covalent organic framework-based approach to regulating the catalyst layer microstructure can achieve synergistic optimization of mass transfer and water management, significantly improving the operational performance and stability of the AEMWE device under high current density conditions.

[0056] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an anion exchange membrane electrode, characterized in that, Includes the following steps: S1. An anode catalyst slurry comprising a hydrophobic covalent organic framework material, an anode catalyst, an anion exchange ionomer, and a solvent; the hydrophobic covalent organic framework material is selected from β-keto-enamine COFs with fluorinated substituted aromatic structural units or benzotriazolyl β-keto-enamine COFs modified with alkyl side chains; the β-keto-enamine COF with fluorinated substituted aromatic structural units is COF-TpPa-CF3; the benzotriazolyl β-keto-enamine COF modified with alkyl side chains is COF-TzDa-octyl; S2. Prepare a cathode catalyst slurry comprising a cathode catalyst, anion exchange polymer, and a solvent; S3. The anode catalyst slurry and cathode catalyst slurry are sprayed or coated onto both sides of the anion exchange membrane or gas diffusion layer, respectively, and after heat treatment, an anion exchange membrane electrode is obtained.

2. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, The hydrophobic covalent organic framework material has a particle size of 1-10 μm and a pore size of 1-5 nm.

3. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, The mass ratio of the hydrophobic covalent organic framework material, the anode catalyst, and the anion exchange ionomer is 1:15-50:0.3-3; and / or, the mass ratio of the cathode catalyst and the anion exchange ionomer is 1:0.15-0.

35.

4. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, The anode catalyst is a nickel-molybdenum alloy, a nickel-iron alloy, a nickel-iron oxide hydroxyl compound, a nickel-iron layered double hydroxide, a nickel-iron oxide, a nickel-cobalt spinel oxide, cobalt tetroxide, a nickel-manganese oxide, a lanthanum-nickel oxide, a barium-strontium-cobalt-iron oxide, an iridium oxide, an iridium black, or an iridium-ruthenium alloy oxide.

5. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, The cathode catalyst is nickel, nickel-iron alloy, nickel-cobalt alloy, nickel-molybdenum alloy, cobalt-iron alloy, cobalt tetroxide, iron oxide, nickel-iron oxide, nickel-iron hydroxide, platinum-carbon, platinum-rhodium-carbon, platinum black, or palladium.

6. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, In steps S1 and S2, the solvent is a mixture of organic solvent and water. The organic solvent is at least one of tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide, isopropanol, and dichloromethane. The volume ratio of the organic solvent to water is 1:4 to 4:

1.

7. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, In step S3, the slurry is sprayed or coated using either catalyst coating membrane technology or catalyst coating substrate technology; when using catalyst coating membrane technology, the loading of the anolyte catalyst layer on the anion exchange membrane surface is 0.1-5.0 mg•cm. -2 The loading of the cathode catalyst layer on the surface of the anion exchange membrane was 0.1-5.0 mg•cm. -2 When using catalyst coating substrate technology, the loading of the anolyte catalyst layer on the gas diffusion layer surface is 0.5-4.0 mg•cm. -2 The loading of the cathode catalyst layer on the surface of the gas diffusion layer is 0.5-4.0 mg•cm. -2 .

8. The method for preparing the anion exchange membrane electrode according to claim 1, characterized in that, In step S3, the heat treatment temperature is 40-110℃ and the time is 1-12 hours.

9. An anion exchange membrane electrode prepared by the method according to any one of claims 1-8.

10. The application of the anion exchange membrane electrode according to claim 9 in water electrolysis for hydrogen production.

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