Proton conductive hydrophilic polymer for self-humidifying membrane electrode and preparation method and application thereof

Abstract

The application belongs to the technical field of self-humidifying membrane electrode, and relates to a proton conductive hydrophilic polymer for a self-humidifying membrane electrode and a preparation method and application thereof. The preparation method comprises the following steps: 2-acrylamido-2-methylpropanesulfonic acid, amino or hydroxyl-containing olefin monomer, potassium persulfate, tetramethylethylenediamine and N,N'-methylenebisacrylamide are dissolved in water according to a molar ratio of 1:(0.05-0.15):(0.001-0.004):(0.002-0.01):(0.04-0.14) and uniformly mixed; the mixed solution is reacted at 50-70 DEG C for 6-12 h to obtain a crosslinked polymer; the crosslinked polymer is filtered, washed and dried, and the hydrophilic polymer is obtained; the amino or hydroxyl-containing olefin monomer is at least one of methacrylamide, hydroxyethyl methacrylate and hydroxypropyl methacrylate. The side chain of the hydrophilic polymer is rich in sulfonic acid groups and amino / hydroxyl groups, and the hydrophilic polymer has good hydrophilicity and proton conductivity.

Description

Technical Field

[0001] This invention belongs to the field of self-humidifying membrane electrode technology, specifically relating to a proton-conductive hydrophilic polymer for self-humidifying membrane electrodes, its preparation method, and its application. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] During the operation of a proton exchange membrane fuel cell (PEMFC), protons in the membrane electrode assembly require a water-rich environment to be effectively transported to the cathode for reaction. This necessitates that the catalyst layer and proton exchange membrane in the membrane electrode assembly maintain a well-wetted environment. When the water content is insufficient or even absent, the proton conductivity will drop sharply or even be lost. Therefore, maintaining sufficient water content in the proton exchange membrane and catalyst layer is crucial for ensuring the stable operation of PEMFC.

[0004] Under high temperature and low humidity conditions, the product water generated at the cathode in PEMFC is quickly evaporated or carried out of the battery by excess reactants. This moisture cannot provide a good wetting environment for the perfluorosulfonic acid resin and proton exchange membrane in the catalyst layer. Therefore, in order to keep the perfluorosulfonic acid resin and perfluorosulfonic acid membrane in the catalyst layer wetted, humidification equipment is often used to perform additional humidification treatment on the reactants before they enter the battery. However, these additional humidification devices increase the battery size and cost, and also make the battery system more complex, thus hindering the commercial development of the battery.

[0005] Existing research has found that by adding a thin layer of hydrophilic oxide (such as SiO2, TiO2, Al2O3) to the gas diffusion layer to prepare a self-humidifying gas diffusion layer, under high relative humidity conditions, the hydrophilic oxide can absorb excess moisture from the catalyst layer and discharge it from the battery, preventing flooding. Under low relative humidity conditions, the hydrophilic oxide can release the absorbed moisture, keeping the membrane electrode in a humidified environment, thereby improving the battery's low-humidity performance. Alternatively, adding a thin layer of Nafion-SiO2 between the proton exchange membrane and the anode catalyst layer can ensure good wetting of both the membrane and the catalyst layer.

[0006] However, neither inorganic materials such as SiO2, Al2O3, and ZnO, nor organic materials such as microcrystalline cellulose and polyvinyl alcohol, inherently possess high proton conductivity. Adding small amounts will not provide a self-humidifying effect, while excessive addition will reduce the proton conductivity of the membrane electrode and increase the battery's internal resistance. Furthermore, simply adding hydrophilic materials (such as SiO2 and γ-Al2O3) results in weak interactions between the hydrophilic materials, leading to aggregation as the reaction proceeds. This aggregation covers the active sites of the catalyst, reduces battery performance, and is detrimental to the long-term stable operation of the fuel cell. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a proton-conductive hydrophilic polymer for self-humidifying membrane electrodes, its preparation method, and its application.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a method for preparing a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, comprising the following steps: Dissolve 2-acrylamido-2-methylpropanesulfonic acid, an amino or hydroxyl-containing olefin monomer, potassium persulfate, tetramethylethylenediamine, and N,N'-methylenebisacrylamide in water at a molar ratio of 1:(0.05-0.15):(0.001-0.004):(0.002-0.01):(0.04-0.14) and mix thoroughly. The mixture was reacted at 50-70℃ for 6-12 hours to obtain the cross-linked polymer. The cross-linked polymer is filtered, washed, and dried to obtain the desired product. The amino or hydroxyl-containing olefin monomers are selected from methacrylamide, hydroxyethyl methacrylate, or hydroxypropyl methacrylate.

[0009] In a second aspect, the present invention provides a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, which is prepared by the aforementioned preparation method.

[0010] Thirdly, the present invention provides the application of the proton-conductive hydrophilic polymer for self-humidifying membrane electrodes in the preparation of self-humidifying membrane electrodes.

[0011] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: This invention prepares a proton-conductive hydrophilic polymer that is insoluble in water and rich in sulfonic acid and amino / hydroxyl groups in its side chains. It exhibits excellent hydrophilicity and proton conductivity. Adding a small amount of this polymer to the anode catalyst layer, between the anode catalyst layer and the proton exchange membrane, or between the anode catalyst layer and the anode gas diffusion layer can significantly improve the low-humidity performance of the fuel cell, achieving a self-humidifying effect. Simultaneously, its cross-linked network porous structure facilitates water vapor transport and prevents loss or aggregation. Furthermore, the catalyst layer can maintain hydration for extended periods under low humidity, mitigating catalyst layer degradation and thus improving the durability and stability of the PEMFC during operation.

[0012] The proton conduction mechanism primarily involves the ionization of sulfonic acid groups under acidic conditions, providing proton carriers and absorbing moisture to form continuous water molecule channels. Protons are rapidly transported along these channels mainly through the Grotthuss hopping mechanism, supplemented by the vehicle diffusion mechanism. Additionally, amino and hydroxyl groups can form hydrogen bond networks under acidic conditions, participating in the proton conduction process. Under high temperature and low humidity conditions, the addition of this cross-linked hydrophilic polymer to the membrane electrode assembly can promote the back diffusion of water from the cathode side to the anode side under the influence of the concentration gradient, thus promoting proton conduction, preventing the catalyst layer and membrane from drying out, maintaining good wetting of the membrane electrode assembly, and preserving high proton conductivity. This allows the fuel cell to achieve similar excellent performance under high humidity conditions while operating under low humidity conditions. Attached Figure Description

[0013] 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.

[0014] Figure 1 These are polarization curves of a fuel cell containing the self-humidifying membrane electrode from Example 1, under different humidity conditions.

[0015] Figure 2 This is a comparison of the polarization curves of fuel cell cells containing the membrane electrodes in Example 1 and Comparative Example 1 at 100% RH.

[0016] Figure 3 This is a comparison graph of the polarization curves of fuel cell cells containing the membrane electrode in Example 1 and Comparative Example 1 at 50% RH.

[0017] Figure 4 This is a comparison of the polarization curves of fuel cell cells containing the membrane electrode in Example 1 and Comparative Example 1 at 20% RH. Detailed Implementation

[0018] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, 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.

[0019] Regarding the issues mentioned in the background art, whether it's inorganic materials such as SiO2, Al2O3, and ZnO, or organic materials such as microcrystalline cellulose and polyvinyl alcohol, they themselves do not possess high proton conductivity. Adding small amounts does not achieve a self-humidifying effect, while excessive addition leads to a decrease in the proton conductivity of the membrane electrode and an increase in the battery's internal resistance. Furthermore, simply adding hydrophilic substances (such as SiO2, γ-Al2O3) results in weak interactions between the hydrophilic materials, leading to aggregation as the reaction proceeds. This aggregation covers the active sites of the catalyst, reduces battery performance, and is detrimental to the long-term stable operation of the fuel cell. Therefore, this invention provides a method for preparing a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, comprising the following steps: Dissolve 2-acrylamido-2-methylpropanesulfonic acid, an amino or hydroxyl-containing olefin monomer, potassium persulfate, tetramethylethylenediamine, and N,N'-methylenebisacrylamide in water at a molar ratio of 1:(0.05-0.15):(0.001-0.004):(0.002-0.01):(0.04-0.14) and mix thoroughly. The mixture was reacted at 50-70℃ for 6-12 hours to obtain the cross-linked polymer. The cross-linked polymer is filtered, washed, and dried to obtain the desired product. The amino or hydroxyl-containing olefin monomer is selected from at least one of methacrylamide, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0020] Methacrylamide, hydroxyethyl methacrylate, or hydroxypropyl methacrylate are chosen as amino or hydroxyl-containing olefin monomers because the amino (-NH2) or hydroxyl (-OH) groups in their molecular structures are highly hydrophilic. These monomers can combine with 2-acrylamido-2-methylpropanesulfonic acid (containing sulfonic acid groups) through free radical copolymerization, resulting in a final polymer side chain rich in both sulfonic acid groups and amino / hydroxyl groups. The amino and hydroxyl groups enhance the polymer's water retention capacity through a hydrogen bond network and also assist in proton conduction, synergistically improving the material's hydrophilicity and proton conductivity with the sulfonic acid groups. Furthermore, all three monomers contain polymerizable double bonds, allowing them to participate in the polymerization reaction with the crosslinking agent N,N'-methylenebisacrylamide, forming a stable three-dimensional crosslinked network structure. This avoids the aggregation or loss problems caused by simply adding hydrophilic substances.

[0021] When the amino or hydroxyl-containing olefin monomers are selected as methacrylamide, hydroxyethyl methacrylate, or hydroxypropyl methacrylate, the preparation routes of the proton-conducting hydrophilic polymers are as follows: ; ; .

[0022] The reaction principle of this invention is as follows: using potassium persulfate as a free radical initiator and tetramethylethylenediamine as a promoter (or a component of the redox initiation system), at a temperature of 50-70°C, 2-acrylamido-2-methylpropanesulfonic acid (an olefin monomer containing sulfonic acid groups) undergoes a free radical copolymerization reaction with an olefin monomer containing amino or hydroxyl groups (selected from at least one of methacrylamide, hydroxyethyl methacrylate, and hydroxypropyl methacrylate). Simultaneously, N,N'-methylenebisacrylamide acts as a crosslinking agent; its two double bonds participate in the polymerization reaction, crosslinking the linear polymer chains through covalent bonds to form a three-dimensional crosslinked network structure, ultimately yielding a water-insoluble crosslinked polymer. During the reaction, the monomers undergo chain growth through the opening of double bonds. The introduction of the crosslinking agent causes the polymer to form a porous network structure, with the side chains retaining sulfonic acid groups (from 2-acrylamido-2-methylpropanesulfonic acid) and amino / hydroxyl groups, endowing the polymer with good hydrophilicity and proton conductivity.

[0023] Excessively high reaction temperatures may lead to an excessively rapid decomposition rate of potassium persulfate initiator, resulting in excessive free radical generation, an overly vigorous reaction, and a tendency to trigger explosive polymerization or side reactions (such as increased chain transfer reactions). This can broaden the polymer's molecular weight distribution, reduce its molecular weight, and even destroy the cross-linked porous network structure, leading to decreased hydrophilicity and proton conductivity of the product. Conversely, excessively low reaction temperatures slow down the decomposition rate of potassium persulfate, resulting in insufficient free radical concentration, difficulty in initiating the polymerization reaction, and a reduced reaction rate. This can lead to low monomer conversion, incomplete cross-linking, and a loose product structure that cannot form a stable three-dimensional network structure, similarly affecting the polymer's water retention capacity and proton conductivity. A reaction temperature of 50-70℃ is essential to ensure stable copolymerization, a moderate degree of cross-linking, and stable product structure and properties.

[0024] In some embodiments, the 2-acrylamido-2-methylpropanesulfonic acid is first subjected to alkaline alumina chromatography to remove the internal polymerization inhibitor before use.

[0025] Alkaline alumina chromatography is a chromatographic separation technique based on the principle of adsorption. It uses alkaline alumina as the stationary phase and utilizes the differences in its adsorption capacity for different compounds to achieve separation and purification.

[0026] Polymer inhibitors can combine with initiators (such as potassium persulfate) or free radicals generated during the reaction, reducing the free radical concentration. This leads to difficulties in initiating the polymerization reaction, a slower rate, or even termination, resulting in low monomer conversion, incomplete cross-linking, and the inability to form a stable three-dimensional cross-linked network structure. Ultimately, this affects key properties of the polymer, such as hydrophilicity, proton conductivity, and water retention capacity. Removing polymer inhibitors is to avoid their inhibitory effect on free radical polymerization and ensure that monomers can successfully participate in the copolymerization reaction.

[0027] In some embodiments, after adding the various raw materials to water in proportion, they are stirred and mixed at 20-30°C for 30-90 minutes.

[0028] In some embodiments, the mixture is reacted at 50-70°C for 6-12 hours to obtain a crosslinked polymer. The reaction temperature can be 50°C, 52°C, 55°C, 58°C, 60°C, 63°C, 65°C, 67°C, or 70°C; the reaction time can be 6 hours, 8 hours, 10 hours, or 12 hours.

[0029] In some embodiments, the washing is performed using distilled water.

[0030] In some embodiments, the drying process involves drying in a vacuum oven at 30-50°C for 12-48 hours. Drying in a vacuum oven at 30-50°C is used to effectively remove moisture while avoiding damage to the polymer structure and properties caused by high temperatures.

[0031] In a second aspect, the present invention provides a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, which is prepared by the aforementioned preparation method.

[0032] Thirdly, the present invention provides the application of the proton-conductive hydrophilic polymer for self-humidifying membrane electrodes in the preparation of self-humidifying membrane electrodes.

[0033] In some embodiments, when preparing a self-humidifying membrane electrode, a proton-conductive hydrophilic polymer is partially or completely replaced with a perfluorosulfonic acid resin, and mixed with a catalyst and a solvent to prepare an anode catalyst slurry.

[0034] In some embodiments, when preparing a self-humidifying membrane electrode, a proton-conductive hydrophilic polymer is mixed uniformly with a solvent and then coated onto a proton exchange membrane. After hot pressing, an anode catalyst layer is coated onto its surface, and a cathode catalyst layer is coated or transferred onto the other side of the proton exchange membrane.

[0035] In some embodiments, when preparing a self-humidifying membrane electrode, a proton-conductive hydrophilic polymer is mixed with a solvent and then coated onto an anode gas diffusion layer to obtain an anode gas diffusion layer with a water-retaining layer.

[0036] The membrane electrode assembly (MEA) is a core component of a fuel cell, typically consisting of a gas diffusion layer, a catalyst layer, and a proton exchange membrane.

[0037] The gas diffusion layer is typically composed of conductive porous substrates such as carbon fiber paper or carbon cloth.

[0038] The embodiments of this application are described in detail below. The embodiments described below are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0039] Example 1 A method for preparing a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode specifically includes the following steps: (1) Dissolve 2-acrylamido-2-methylpropanesulfonic acid (3.7 mmol), N,N'-methylenebisacrylamide (0.3 mmol), potassium persulfate (0.007 mmol), tetramethylethylenediamine (0.02 mmol) and methacrylamide (0.4 mmol) in distilled water (20 mL) and stir at room temperature for 1 h to obtain a mixture; (2) The mixture was heated in an oven at 60 °C for 9 h to react. The polymer generated by the reaction precipitated out of the mixture to obtain a gel precipitate. (3) The gel precipitate obtained in step (2) was filtered and collected, washed with distilled water, and dried in a vacuum oven at 40 °C for 24 h to obtain a proton-conductive hydrophilic polymer.

[0040] The preparation route of the proton-conductive hydrophilic polymer is shown below: .

[0041] The preparation method of the self-humidifying film electrode is as follows: A proton-conducting hydrophilic polymer was mixed with 2g of Pt / C catalyst (50wt%), 30.2ml of isopropanol, and 8.4g of perfluorosulfonic acid resin (10wt%) to prepare an anode catalyst slurry, which was then coated onto one side of the proton exchange membrane at a coating amount of 0.05 mg / cm². 2 The other side of the proton exchange membrane is coated with a cathode catalyst layer of 0.35 mg / cm². 2 Finally, it is assembled with the commercial anode gas diffusion layer and cathode gas diffusion layer to form a self-humidifying membrane electrode.

[0042] The self-humidifying film electrode obtained in this embodiment was assembled into a single cell. The single cell temperature was set to 65°C, and polarization performance tests were conducted at different humidity levels (relative humidity of hydrogen gas and air introduced into the single cell) of 100%RH, 50%RH, and 20%RH. Figure 1 As shown in Table 1, 1A / cm 2 At 0.744V@100%RH, 0.733V@50%RH, and 0.709V@20%RH, the battery exhibits excellent performance over a wide humidity range. After 60 hours of continuous operation at a battery temperature of 65℃ and 20%RH, the single-cell durability (retention rate based on current density at 0.7 V) is shown in Table 2, with a retention rate of 94.4%, demonstrating good battery stability.

[0043] Example 2 The preparation method of the proton-conductive hydrophilic polymer for self-humidifying membrane electrodes specifically includes the following steps: (1) Dissolve 2-acrylamido-2-methylpropanesulfonic acid (3.5 mmol), N,N'-methylenebisacrylamide (0.4 mmol), potassium persulfate (0.01 mmol), tetramethylethylenediamine (0.02 mmol) and methacrylamide (0.2 mmol) in distilled water (20 mL) and stir at room temperature for 1 h to obtain a mixture; (2) The mixture was heated in an oven at 55°C for 10 hours to react. The polymer generated by the reaction precipitated out of the mixture to obtain a gel precipitate. (3) The gel precipitate obtained in step (2) was filtered and collected, washed with distilled water, and dried in a vacuum oven at 40°C for 40 h to obtain a proton-conductive hydrophilic polymer.

[0044] Preparation method of self-humidifying film electrode: The preparation method of the self-humidifying membrane electrode differs from that in Example 1 in that: 1g of the obtained proton-conductive hydrophilic polymer is mixed evenly with 10ml of isopropanol and then coated onto a proton exchange membrane to obtain a proton exchange membrane with a water-retaining layer. After hot pressing, an anode catalyst layer (containing 50wt% Pt / C catalyst and perfluorosulfonic acid ionomer) is coated on the water-retaining layer side of the proton exchange membrane, and a cathode catalyst layer (containing 50wt% Pt / C catalyst and perfluorosulfonic acid ionomer) is coated on the other side. Finally, it is assembled with a commercially available anode gas diffusion layer and cathode gas diffusion layer to form a self-humidifying membrane electrode.

[0045] The self-humidifying film electrode assembly of the single cell obtained in this embodiment was subjected to polarization performance tests at different humidity levels of 100%RH, 50%RH, and 20%RH, with a polarization performance of 1A / cm. 2 At 0.740V@100%RH, 0.730V@50%RH, and 0.705V@20%RH (Table 1), the battery exhibits excellent performance over a wide humidity range. In the durability test, the current density retention rate was 91.3% (Table 2), demonstrating good battery stability.

[0046] Example 3 The preparation method of the proton-conductive hydrophilic polymer for self-humidifying membrane electrodes specifically includes the following steps: (1) Dissolve 2-acrylamido-2-methylpropanesulfonic acid (3.7 mmol), N,N'-methylenebisacrylamide (0.2 mmol), potassium persulfate (0.006 mmol), tetramethylethylenediamine (0.03 mmol) and methacrylamide (0.3 mmol) in distilled water (20 mL) and stir at room temperature for 1 h to obtain a mixture; (2) The mixture was heated in an oven at 70°C for 6 hours to react. The polymer generated by the reaction precipitated out of the mixture to obtain a gel precipitate. (3) The gel precipitate obtained in step (2) was filtered and collected, washed with distilled water, and dried in a vacuum oven at 50°C for 12 h to obtain a proton-conductive hydrophilic polymer.

[0047] Preparation method of self-humidifying film electrode: The preparation method of the self-humidifying membrane electrode differs from that in Example 1 in that: 1g of the obtained proton-conductive hydrophilic polymer is mixed evenly with 20ml of ethanol, and then coated onto a commercial Jiazi anode gas diffusion layer to obtain the anode self-humidifying gas diffusion layer. This anode self-humidifying gas diffusion layer is then matched with a self-made three-in-one catalyst coating film CCM (containing 50wt% Pt / C catalyst, perfluorosulfonic acid ionomer, and proton exchange membrane) and a commercial Jiazi cathode gas diffusion layer to form the self-humidifying membrane electrode. Everything else is the same as in Example 1.

[0048] The self-humidifying film electrode prepared in this way achieves a speed of 1 A / cm. 2 At 0.742V@100%RH, 0.731V@50%RH, and 0.707V@20%RH (Table 1), the battery exhibits excellent performance over a wide humidity range. In the durability test, the current density retention rate was 93.3% (Table 2), demonstrating good battery stability.

[0049] Example 4 The preparation method of the proton-conductive hydrophilic polymer is the same as in Example 1, except that methacrylamide is replaced with hydroxyethyl methacrylate in the preparation of the proton-conductive hydrophilic polymer. Everything else is the same as in Example 1.

[0050] The self-humidifying film electrode prepared in this way achieves a speed of 1 A / cm. 2 At 0.743V@100%RH, 0.732V@50%RH, and 0.708V@20%RH (Table 1), the battery exhibits excellent performance over a wide humidity range. In the durability test, the current density retention rate was 93.4% (Table 2), demonstrating good battery stability.

[0051] Example 5 The preparation method of the proton-conductive hydrophilic polymer is the same as in Example 1, except that when preparing the proton-conductive hydrophilic polymer, methacrylamide (0.4 mmol) is replaced with methacrylamide (0.2 mmol) and hydroxyethyl methacrylate (0.2 mmol). Everything else is the same as in Example 1.

[0052] The prepared self-humidifying film electrode has an efficiency of 1 A / cm. 2At 0.745V@100%RH, 0.732V@50%RH, and 0.709V@20%RH (Table 1), the battery exhibits excellent performance over a wide humidity range. In durability testing, the current density retention rate is 93.5% (Table 2), demonstrating good battery stability.

[0053] Example 6 The preparation method of the proton-conductive hydrophilic polymer is the same as that in Example 1, except that when preparing the proton-conductive hydrophilic polymer, methacrylamide (0.4 mmol) is replaced with methacrylamide (0.2 mmol), hydroxyethyl methacrylate (0.1 mmol) and hydroxypropyl methacrylate (0.1 mmol).

[0054] The self-humidifying film electrode prepared in this way achieves a speed of 1 A / cm. 2 At 0.744V@100%RH, 0.731V@50%RH, and 0.707V@20%RH (Table 1), the battery exhibits excellent performance over a wide humidity range. In the durability test, the current density retention rate was 92.5% (Table 2), demonstrating good battery stability.

[0055] Comparative Example 1 The difference from Example 1 is that no proton-conductive hydrophilic polymer is added to the anode catalyst slurry, and neither the proton exchange membrane nor one side of the anode gas diffusion layer is coated with a proton-conductive hydrophilic polymer.

[0056] The polarization performance of this membrane electrode assembly was tested at different humidity levels (100%RH, 50%RH, and 20%RH). Figure 2 , Figure 3 , Figure 4 As shown in Table 1, 1A / cm 2 At 0.743V@100%RH, 0.696V@50%RH, and 0.595V@20%RH, humidity significantly affected performance. Performance at high humidity was close to that of the example, while performance at low humidity was poor. Performance decreased significantly as humidity decreased. In the durability test, the current density retention rate dropped rapidly to 1.35% after only 15 hours of operation (as shown in Table 2), indicating rapid deterioration of the membrane electrode in a short period of time.

[0057] Table 1

[0058] Table 2

[0059] 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 method for preparing a proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, characterized in that: Includes the following steps: Dissolve 2-acrylamido-2-methylpropanesulfonic acid, an amino or hydroxyl-containing olefin monomer, potassium persulfate, tetramethylethylenediamine, and N,N'-methylenebisacrylamide in water at a molar ratio of 1:(0.05-0.15):(0.001-0.004):(0.002-0.01):(0.04-0.14) and mix thoroughly. The mixture was reacted at 50-70℃ for 6-12 hours to obtain the cross-linked polymer. The cross-linked polymer is filtered, washed, and dried to obtain the desired product. The amino or hydroxyl-containing olefin monomer is selected from at least one of methacrylamide, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

2. The method for preparing the proton-conductive hydrophilic polymer for a self-humidifying membrane electrode according to claim 1, characterized in that: Before use, the 2-acrylamido-2-methylpropanesulfonic acid is first subjected to alkaline alumina chromatography to remove the internal polymerization inhibitor.

3. The method for preparing the proton-conductive hydrophilic polymer for a self-humidifying membrane electrode according to claim 1, characterized in that: After adding each ingredient to water in the specified proportions, stir and mix at 20-30℃ for 30-90 minutes.

4. The method for preparing the proton-conductive hydrophilic polymer for a self-humidifying membrane electrode according to claim 1, characterized in that: The mixture is reacted at 50-70℃ for 6-12 hours to obtain the cross-linked polymer.

5. The method for preparing the proton-conductive hydrophilic polymer for a self-humidifying membrane electrode according to claim 1, characterized in that: The washing process involves using distilled water.

6. The method for preparing the proton-conductive hydrophilic polymer for a self-humidifying membrane electrode according to claim 1, characterized in that: The drying process involves drying in a vacuum oven at 30-50°C for 12-48 hours.

7. A proton-conductive hydrophilic polymer for a self-humidifying membrane electrode, characterized in that: It is prepared by any one of the preparation methods described in claims 1-6.

8. The application of the proton-conductive hydrophilic polymer according to claim 7 in the preparation of a self-humidifying membrane electrode.

9. The application according to claim 8, characterized in that: In the preparation of self-humidifying membrane electrodes, proton-conductive hydrophilic polymers are partially or completely replaced with perfluorosulfonic acid resins and mixed with catalysts and solvents to prepare anode catalyst slurry. Alternatively, in the preparation of the self-humidifying membrane electrode, after uniformly mixing the proton-conductive hydrophilic polymer with a solvent, it is coated onto the proton exchange membrane. After hot pressing, an anode catalyst layer is coated on its surface, and a cathode catalyst layer is coated or transferred onto the other side of the proton exchange membrane.

10. The application according to claim 8, characterized in that: In the preparation of the self-humidifying membrane electrode, a proton-conductive hydrophilic polymer is mixed with a solvent and then coated onto the anode gas diffusion layer to obtain an anode gas diffusion layer with a water-retaining layer.

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