COF material for self-humidifying membrane electrode and preparation method and application thereof
By grafting sulfonate groups into COF materials, a hydrophilic group structure with high specific surface area and high porosity is formed, which solves the problems of non-conductivity of hydrophilic materials and instability of phosphoric acid in PEMFC self-humidification technology, realizing a high-performance and stable membrane electrode, and improving proton conductivity and environmental adaptability.
Patent Information
- Application Number
- CN202611530145.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-30
- Publication Date
- 2026-11-03
AI Technical Summary
Existing proton exchange membrane fuel cells (PEMFCs) suffer from problems in self-humidification technology, such as the non-conductivity and non-proton conductivity of hydrophilic materials, and the low and unstable proton conductivity of phosphate, which leads to increased ohmic impedance and catalyst poisoning, affecting battery performance and lifespan.
The COF material for self-humidifying membrane electrodes is adopted. By grafting sulfonate groups into the COF material, a hydrophilic group structure with high specific surface area and high porosity is formed, which improves water retention capacity and proton conductivity, and ensures stability through chemical grafting.
It achieves high-performance membrane electrodes under both high and low humidity conditions, with strong environmental adaptability, stable and reliable sulfonate groups that do not leak with liquid water, significantly improved durability and reliability, and reduced ohmic impedance.
Smart Images
Figure CN123026767A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fuel cell technology, and in particular to a COF material for a self-humidifying membrane electrode, its preparation method, and its application. Background Technology
[0002] Proton exchange membrane fuel cells (PEMFCs) require sufficient moisture to maintain the high proton conductivity of the proton exchange membrane for efficient operation. Traditional PEMFCs use an external humidification system to humidify the reaction gas. However, this method not only complicates the PEMFC system and increases manufacturing costs, but also results in low dynamic response capability, difficulty in real-time matching of changes in operating conditions, poor environmental adaptability, damage to battery performance and lifespan, and hinders the commercialization of PEMFCs.
[0003] In existing self-humidifying technologies, adding hydrophilic substances to the catalyst layer is a relatively simple and efficient strategy. However, commonly used hydrophilic substances (such as inorganic materials like silicon dioxide and titanium dioxide, and organic materials like polyvinyl alcohol) have the disadvantage of being non-conductive and non-proton-conductive. Although adding these substances to the catalyst layer can improve the water retention capacity of the membrane electrode under low humidity, it will also lead to an increase in ohmic impedance and a reduction in battery power.
[0004] In existing technologies, phosphoric acid, which has proton conductivity, is embedded in the pores of COF materials in a physically confined manner. Although this achieves a simultaneous improvement in the hydrophilicity and proton conductivity of COF materials in the short term, the proton conductivity of phosphoric acid is low at normal operating temperatures. Phosphoric acid molecules are not stable enough as they are physically confined in the pores. During battery operation, the generated liquid water can easily carry away phosphoric acid molecules, leading to phosphoric acid molecule loss and a decrease in proton conductivity. The lost phosphoric acid molecules can poison the catalyst and cause irreversible damage to the membrane electrode. Summary of the Invention
[0005] In view of this, the present invention provides a COF material for a self-humidifying membrane electrode, its preparation method, and its application. The COF material provided by the present invention has abundant hydrophilic groups, which improves water retention capacity while also enhancing the proton conductivity of the membrane electrode.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a COF material for a self-humidifying membrane electrode, which includes the following structural units: ; In the structural formula, the wavy line represents the connection of repeating units of that type.
[0007] The COF material provided by this invention not only possesses abundant hydrophilic groups such as -NH- and -SO3H, but also boasts advantages such as high specific surface area and high porosity, making it an excellent water-retaining material. Grafting sulfonate groups into the COF material enhances both water retention capacity and proton conductivity of the membrane electrode. When the self-humidifying membrane electrode COF material of this invention is incorporated into the proton exchange membrane, it exhibits higher proton conductivity and better stability compared to phosphoric acid, and it does not leak or poison the catalyst during battery operation.
[0008] Secondly, the present invention provides a method for preparing the above-mentioned COF material for a self-humidifying film electrode, comprising the following steps: Melamine and terephthalaldehyde are mixed in a mass ratio of 1:1.5-2 and dissolved in a solvent. The mixture is then reacted under anhydrous and oxygen-free conditions at a temperature of 150-200℃ for 60-100 hours to obtain the reaction product. The reaction product was then subjected to sulfonation and dried to obtain the final product.
[0009] The reaction route is shown below: ; .
[0010] Furthermore, the solvent is dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane, tetrahydrofuran, etc., preferably anhydrous dimethyl sulfoxide.
[0011] Furthermore, the mass of the solvent is 45-60 times the mass of melamine.
[0012] Furthermore, the reaction temperature under the anhydrous and oxygen-free conditions is 150-180℃; the reaction time is 60-80h.
[0013] Furthermore, the mass ratio of melamine to terephthalaldehyde is 1:1.5-1.8.
[0014] Furthermore, the reaction under anhydrous and oxygen-free conditions is carried out under an inert atmosphere.
[0015] Furthermore, the sulfonation reaction temperature is 60-80℃, and the reaction time is 40-120 min.
[0016] Furthermore, the sulfonating agent in the sulfonation reaction is concentrated sulfuric acid or sulfur trioxide.
[0017] Thirdly, the present invention provides the application of the COF material for the self-humidifying membrane electrode described in the first aspect in the preparation of the self-humidifying membrane electrode.
[0018] The self-humidifying membrane electrode provided by this invention exhibits high performance under both high and low humidity conditions and strong environmental adaptability. The sulfonate group is chemically grafted onto the COF material, ensuring stability and reliability. It will not be lost with liquid water or poison the catalyst, significantly improving durability and reliability. The self-humidifying membrane electrode provided by this invention simultaneously enhances the hydrophilicity and proton conductivity of the membrane electrode, breaking the paradox that the two cannot be simultaneously achieved. It effectively reduces ohmic impedance while improving water retention.
[0019] Fourthly, the present invention provides a self-humidifying membrane electrode, the raw material of which includes the COF material for the self-humidifying membrane electrode described in the first aspect.
[0020] This invention employs a strategy of grafting proton-conductive sulfonate groups onto a hydrophilic porous COF material to prepare a high-performance, high-durability, wide-humidity-adaptive self-humidifying membrane electrode. The hydrophilic porous COF material not only possesses abundant hydrophilic groups such as -NH- and -SO3H, but also exhibits advantages like high specific surface area and high porosity, making it an excellent hydrophilic material. Proton-conductive sulfonate grafting involves sulfonating the prepared COF material with concentrated sulfuric acid or other sulfonating agents at high temperatures, followed by a substitution reaction to graft sulfonate groups onto the electrophilic positions adjacent to the benzene ring. The introduction of sulfonate groups provides higher proton conductivity compared to phosphoric acid and is extremely stable, preventing loss and catalyst poisoning during battery operation.
[0021] Fifthly, the present invention provides a method for preparing the self-humidifying film electrode described in the fourth aspect, comprising the following steps: The self-humidifying membrane electrode COF material prepared by the method described in the first aspect or the preparation method described in the second aspect is mixed with the anode catalyst, deionized water, ethanol and Nafion solution, and dispersed to obtain the anode catalyst layer slurry. The cathode catalyst, deionized water, ethanol, and Nafion solution were mixed and dispersed to obtain a cathode catalyst slurry. The anodic catalyst layer slurry and the cathode catalyst layer slurry are sprayed onto both sides of the proton exchange membrane to obtain the self-humidifying membrane electrode.
[0022] Furthermore, the anode and cathode catalysts are Pt / C catalysts; the concentration of the Nafion solution is 4-6%, where % is a mass percentage.
[0023] Furthermore, in the anode catalyst slurry, the mass ratio of COF material to anode catalyst is 0.01-0.06:1.
[0024] Preferably, in the anode catalyst slurry, the mass ratio of anode catalyst, deionized water, ethanol and Nafion solution is 0.8-1:3.5-6:35-60:4-8.
[0025] Furthermore, the Pt loading at the anode is 0.04-0.06 mg / cm³. 2 The Pt loading at the cathode is 0.3-0.5 mg / cm³. 2 .
[0026] Furthermore, in the cathode catalyst slurry, the mass ratio of cathode catalyst, deionized water, ethanol and Nafion solution is 0.8-1:3.5-6:35-60:4-8.
[0027] Compared with the prior art, the present invention has achieved the following beneficial effects: The COF material provided by this invention has abundant hydrophilic groups, which enhances water retention capacity and proton conductivity of the membrane electrode. Applying the COF material to membrane electrode fabrication results in membrane electrodes with high performance under both high and low humidity conditions, exhibiting strong environmental adaptability. Simultaneously, it improves the hydrophilicity and proton conductivity of the membrane electrode. Sulfonate groups are chemically grafted onto the COF material, ensuring stability and reliability, preventing loss with liquid water, and avoiding catalyst poisoning, thus significantly improving durability and reliability. Attached Figure Description
[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0029] Figure 1 This is the infrared spectrum of the COF material prepared in Example 1. Detailed Implementation
[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0031] Explanation of related terms Proton exchange membrane: A semi-permeable polymer membrane that conducts only protons and isolates electrons and gases.
[0032] Self-humidifying membrane electrode: A membrane electrode that does not require external humidification equipment and relies on water generated by its own electrochemical reaction and structural design to achieve a self-balancing supply of moisture between the membrane and the catalyst layer.
[0033] Covalent organic frameworks are a class of porous materials composed of organic molecules linked by strong covalent bonds and characterized by long-range order.
[0034] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0035] Example 1 A method for preparing COF material for a self-humidifying film electrode, the specific steps of which are as follows: (1) Add 4.695 g of melamine, 7.5 g of terephthalaldehyde and 232.5 g of anhydrous dimethyl sulfoxide to a three-necked flask. Install a condenser and a three-way valve on top of the three-necked flask. Tie a balloon to the top of the three-way valve with a rubber band and plug the other two openings of the three-necked flask with a rubber stopper. Seal all connections with sealing film. Place the reaction system in an oil bath at 180°C under an anhydrous and oxygen-free reaction environment and let it stand under reflux for 72 h to obtain COF material.
[0036] The reaction equation for COF materials is shown below: .
[0037] (2) Using 50 g of 98% concentrated sulfuric acid, the COF material prepared in step (1) was subjected to a sulfonation reaction at approximately 70°C for 60 min. Sulfonate groups with proton conductivity were grafted onto the adjacent positions of the benzene ring in the COF. After thorough drying, the sulfonate-grafted COF material was obtained. Its chemical reaction formula is as follows: .
[0038] Its infrared spectrum is as follows Figure 1 As shown, it can be seen in the infrared spectrum that at 1000 cm⁻¹ -1 The nearby peak is the SO stretching vibration peak, at 1250 cm⁻¹. -1 The nearby peak represents the S=O stretching vibration of the sulfonate group, confirming successful grafting of the sulfonate group. (1150 cm⁻¹) -1 The nearby peak is the NH stretching vibration peak, at 1400 cm⁻¹. -1 The vicinity is near the triazine ring vibration peak, 1550 cm⁻¹. -1 The nearby peak is the C=O stretching vibration peak, at 2900 cm⁻¹. -1 The nearby peak is the CH stretching vibration peak, at 3300 cm⁻¹. -1 The presence of NH characteristic peaks nearby confirms the successful synthesis of the sulfonic acid-grafted COF material.
[0039] Example 2 A method for preparing a self-humidifying film electrode, the specific steps of which are as follows: (1) Weigh 0.042 g of sulfonic acid-grafted COF material prepared in Example 1 into a 150 mL beaker using an analytical balance. Then add 1.4 g EC300J 60% Pt / C catalyst, 5.676 g deionized water, 7.84 g 5% Nafion solution and 56.764 g anhydrous ethanol to the beaker.
[0040] (2) Use Primix to disperse the above slurry between 0℃ and 10℃ for 20 min (divided into two 10 min intervals) to obtain a uniform and stable anode catalyst layer slurry.
[0041] (3) Weigh 1.4 g EC300J 60% Pt / C catalyst, 5.676 g deionized water, 7.84 g 5% Nafion solution and 56.764 g anhydrous ethanol into a 150 mL beaker using an analytical balance.
[0042] (4) The above slurry was dispersed at 0℃-10℃ for 20 min (divided into two parts, 10 min each time) using a high-speed disperser / emulsifier Primix to obtain a uniform and stable cathode catalyst layer slurry.
[0043] (5) The anode catalyst layer slurry and the cathode catalyst layer slurry are respectively sprayed onto both sides of the proton exchange membrane, and dried to obtain the membrane electrode, wherein the Pt loading of the anode is 0.05 mg / cm³. 2 The Pt loading at the cathode is 0.4 mg / cm³. 2 .
[0044] Example 3 A method for preparing COF material for a self-humidifying film electrode, the specific steps of which are as follows: (1) Add 4.213 g of melamine, 7.54 g of terephthalaldehyde, and 245.6 g of anhydrous dimethyl sulfoxide to a three-necked flask. Install a condenser and a three-way valve on top of the three-necked flask. Tie a balloon to the top of the three-way valve with a rubber band and plug the other two openings of the three-necked flask with a rubber stopper, ensuring that all connections are sealed with sealing film. Under an anhydrous and oxygen-free reaction environment, place the reaction system in an oil bath at 170°C and allow it to stand under reflux for 80 h to obtain COF material.
[0045] (2) Use 50 g of concentrated sulfuric acid with a mass fraction of 98% to carry out a sulfonation reaction with the COF material prepared in step (1) at a temperature of 80°C for 100 min, and then graft sulfonate groups with proton conductivity onto the ortho position of the benzene ring in the COF. After thorough drying, the target product is obtained.
[0046] The self-humidifying membrane electrode was prepared using the preparation method of Example 2.
[0047] Comparative Example 1 The preparation method of phosphorylated COF material is as follows: (1) The preparation of COF material is the same as in Example 1.
[0048] Specifically, 4.695 g of melamine, 7.5 g of terephthalaldehyde, and 232.5 g of anhydrous dimethyl sulfoxide were added to a three-necked flask. A condenser and a three-way valve were then installed on top of the flask. A balloon was tied to the top of the three-way valve with a rubber band, and the other two openings of the three-necked flask were sealed with rubber stoppers. All connections were sealed with sealing film. Under an anhydrous and oxygen-free reaction environment, the reaction system was placed in an oil bath at 180°C and allowed to stand under reflux for 72 hours.
[0049] (2) The COF material prepared in step (1) is vacuum treated at 120°C for 24 hours to remove the residual solvent and air in the pores.
[0050] The mixture was then cooled to 70°C and kept under vacuum. A 25 wt% phosphoric acid solution was thoroughly mixed with the COF material at a mass ratio of 100:1. The vacuum was then removed to press the phosphoric acid molecules into the pores of the COF. After centrifugation at room temperature, washing, and vacuum drying, the phosphoric acid-loaded COF material was obtained.
[0051] Comparative Example 2 This comparative example provides a method for preparing a membrane electrode, the specific steps of which are as follows: (1) Weigh 2.8 g EC300J 60% Pt / C catalyst, 11.325 g deionized water, 15.68 g 5% Nafion solution and 113.528 g anhydrous ethanol into a 250 mL beaker using an analytical balance.
[0052] (2) Use Primix to disperse the above slurry between 0℃ and 10℃ for 20 min (divided into two 10 min intervals) to obtain a uniform and stable anode catalyst layer slurry and cathode catalyst layer slurry.
[0053] (3) The anode catalyst layer slurry and the cathode catalyst layer slurry are respectively sprayed onto both sides of the proton exchange membrane, and dried to obtain the membrane electrode, wherein the Pt loading of the anode is 0.05 mg / cm³. 2 The Pt loading at the cathode is 0.4 mg / cm³. 2 .
[0054] Comparative Example 3 This comparative example provides a method for preparing a membrane electrode, the specific steps of which are as follows: (1) Weigh 2.8 g EC300J 60% Pt / C catalyst, 11.325 g deionized water, 15.68 g 5% Nafion solution, 113.528 g anhydrous ethanol and 0.006 g nano silica into a 250 mL beaker using an analytical balance.
[0055] (2) Use Primix to disperse the above slurry between 0℃ and 10℃ for 20 min (divided into two 10 min intervals) to obtain a uniform and stable anode catalyst layer slurry and cathode catalyst layer slurry.
[0056] (3) The anode catalyst layer slurry and the cathode catalyst layer slurry are respectively sprayed onto both sides of the proton exchange membrane, and dried to obtain the membrane electrode, wherein the Pt loading of the anode is 0.05 mg / cm³. 2 The Pt loading at the cathode is 0.4 mg / cm³. 2 .
[0057] Comparative Example 4 Phosphorylated COF material is used to prepare a film electrode: (1) Weigh 0.042 g of the phosphorylated COF material prepared in Comparative Example 1 into a 150 mL beaker using an analytical balance. Then add 1.4 g EC300J 60% Pt / C catalyst, 5.676 g deionized water, 7.84 g 5% Nafion solution and 56.764 g anhydrous ethanol to the beaker.
[0058] (2) Use Primix to disperse the above slurry between 0℃ and 10℃ for 20 min (divided into two 10 min intervals) to obtain a uniform and stable anode catalyst layer slurry.
[0059] (3) Weigh 1.4 g EC300J 60% Pt / C catalyst, 5.676 g deionized water, 7.84 g 5% Nafion solution and 56.764 g anhydrous ethanol using an analytical balance, and add the above substances to a 150 mL beaker.
[0060] (4) Use Primix to disperse the above slurry between 0℃ and 10℃ for 20 min (divided into two 10 min intervals) to obtain a uniform and stable cathode catalyst slurry.
[0061] (5) The anode catalyst layer slurry and the cathode catalyst layer slurry are sprayed onto both sides of the proton exchange membrane, and dried to form a membrane electrode, wherein the Pt loading of the anode is 0.05 mg / cm³. 2 The Pt loading at the cathode is 0.4 mg / cm³. 2 .
[0062] The membrane electrodes prepared in Examples 2-3 and Comparative Examples 2-4 were subjected to single-cell performance tests under different humidity conditions. The test conditions were as follows: humidity 100% and 20%, anode and cathode pressure 70 kPa, battery test temperature 75 °C, anode and cathode dew point temperatures 75 °C and 40 °C, respectively, anode metering flow rate 1.5, and cathode metering flow rate 2.5. A current corresponding to 0.4 V was selected as the starting point, and derating tests were performed at 5 A intervals, with a dwell time of 2 min at each point, until the current dropped to 0 A. The current was recorded at 1 A / cm. 2 The corresponding voltage (V) and 2 A / cm 2 The corresponding voltage (V) is shown in Table 1. The test results are shown in Table 1.
[0063] Table 1 Single cell data before 200 h durability test
[0064] As can be seen from the data in Table 1, Example 2 exhibited the best performance under both high and low humidity conditions. This is because the sulfonate COF material formed a continuous proton conduction network in the anode catalyst layer, which greatly reduced the ohmic resistance. At the same time, under low humidity conditions, the sulfonate COF material, with its porous structure and hydrophilic groups, locked in a large amount of water, ensuring sufficient wetting of the proton exchange membrane. Under high humidity conditions, the sulfonate COF material, with its abundant pore structure, facilitated the storage and discharge of liquid water, effectively preventing water flooding and under-gas phenomenon, thus exhibiting the best performance under both high and low humidity conditions.
[0065] Because the raw material ratio during the synthesis of COF in Example 3 was slightly smaller, the COF skeleton of Example 3 was slightly smaller than that of Example 1, and the pore structure was not as rich, resulting in its performance being slightly lower than that of Example 1.
[0066] Comparative Example 2, lacking water-retaining components, exhibited poor performance under low humidity. Although Comparative Example 3 incorporated hydrophilic nano-silica, improving hydrophilicity and thus performance under low humidity, the introduction of non-conductive and non-proton-conducting nano-silica increased the battery's contact resistance, resulting in a decrease in battery performance compared to Example 1.
[0067] Comparative Example 4, due to the addition of phosphoric acid-loaded COF material, exhibits good performance under both high and low humidity conditions. However, because the proton conductivity of phosphoric acid is lower than that of sulfonate under battery testing conditions of 75°C, its battery performance is poor.
[0068] In addition, single-cell 200-h durability tests were conducted on the membrane electrodes prepared in Examples 2-3 and Comparative Examples 2-4. The durability conditions were 0.67 V stable for 200 h, and the battery performance was tested after the durability test.
[0069] The test conditions were as follows: humidity 100% and 20% respectively; anode and cathode pressure 70 kPa; battery test temperature 75 ℃; anode and cathode dew point temperatures 75 ℃ and 40 ℃ respectively; anode metering specific flow rate 1.5; and cathode metering specific flow rate 2.5. The current corresponding to 0.4 V was selected as the starting point, and descent tests were performed at 5 A intervals, with a dwell time of 2 minutes at each point, until the current dropped to 0 A. The current was recorded at 1 A / cm. 2 The corresponding voltage (V) and 2 A / cm 2 The corresponding voltage (V) is shown in Table 2. The test results are shown in Table 2.
[0070] Table 2 Single cell data after 200 h durability test
[0071] As shown in Table 2, after 200 hours of durability testing, Examples 2-3 all exhibited only slight performance degradation, remaining within the normal range and demonstrating good durability. However, Comparative Example 4 showed a significant performance decline after the durability test. This is because the phosphoric acid molecules in Comparative Example 4 were physically confined within the COF pores, making them less secure. During battery operation, some phosphoric acid was lost along with the liquid water generated by the battery. This resulted in a decrease in proton conductivity and, more importantly, the lost phosphoric acid poisoned the catalyst, leading to a severe decline in battery performance.
[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A COF material for a self-humidifying film electrode, characterized in that, It includes the following structural units: ； In the structural formula, the wavy line represents the connection of that type of structural unit.
2. The method for preparing COF material for self-humidifying film electrodes as described in claim 1, characterized in that, Includes the following steps: Melamine and terephthalaldehyde are mixed in a mass ratio of 1:1.5-2 and dissolved in a solvent. The mixture is then reacted under anhydrous and oxygen-free conditions at a temperature of 150-200℃ for 60-100 hours to obtain the reaction product. The reaction product was then subjected to sulfonation and dried to obtain COF material.
3. The preparation method according to claim 2, characterized in that, The solvent is selected from at least one of dimethyl sulfoxide, N,N-dimethylformamide, 1,4-dioxane or tetrahydrofuran; And / or, the mass of the solvent is 45-60 times the mass of melamine.
4. The preparation method according to claim 2, characterized in that, The reaction temperature under anhydrous and oxygen-free conditions is 150-180℃; the reaction time is 60-80h. And / or, the mass ratio of melamine to terephthalaldehyde is 1:1.5-1.8; And / or, the reaction under anhydrous and oxygen-free conditions is carried out under an inert atmosphere.
5. The preparation method according to claim 2, characterized in that, The sulfonation reaction temperature is 60-80℃, and the reaction time is 40-120 min; And / or, the sulfonating agent in the sulfonation reaction is concentrated sulfuric acid or sulfur trioxide.
6. The application of the COF material for self-humidifying membrane electrodes as described in claim 1 in the preparation of self-humidifying membrane electrodes.
7. A self-humidifying film electrode, characterized in that, The raw materials include the COF material for self-humidifying membrane electrodes as described in claim 1.
8. The method for preparing the self-humidifying film electrode as described in claim 7, characterized in that, Includes the following steps: The self-humidifying membrane electrode COF material prepared by the preparation method described in claim 1 or any one of claims 2 to 5 is mixed and dispersed with an anode catalyst, deionized water, ethanol and Nafion solution to obtain an anode catalyst layer slurry. The cathode catalyst, deionized water, ethanol, and Nafion solution are mixed and dispersed to obtain the cathode catalyst slurry. The anodic catalyst layer slurry and the cathode catalyst layer slurry are sprayed onto both sides of the proton exchange membrane to obtain the self-humidifying membrane electrode.
9. The preparation method according to claim 8, characterized in that, The anode and cathode catalysts are Pt / C catalysts; the Nafion solution concentration is 4-6%, where % is a mass percentage; And / or, in the anode catalyst slurry, the mass ratio of COF material to anode catalyst is 0.01-0.06:1; And / or, in the anode catalyst slurry, the mass ratio of anode catalyst, deionized water, ethanol and Nafion solution is 0.8-1:3.5-6:35-60:4-8.
10. The preparation method according to claim 8, characterized in that, The Pt loading at the anode is 0.04-0.06 mg / cm³. 2 The Pt loading at the cathode is 0.3-0.5 mg / cm³. 2 ; And / or, in the cathode catalyst slurry, the mass ratio of cathode catalyst, deionized water, ethanol and Nafion solution is 0.8-1:3.5-6:35-60:4-8.