Preparation method of frequent start-stop resistant membrane electrode of PEM electrolytic cell

Abstract

The invention provides a preparation method of a frequent start-stop resistant membrane electrode of a PEM electrolytic cell. The preparation method comprises the following steps: providing composite slurry I; coating one side of the proton exchange membrane with the composite slurry I, and drying to obtain a composite layer; coating the surface of the composite layer with anode catalyst slurry containing a catalyst self-repairing material, and drying by adopting a first drying process to obtain an anode catalyst layer; preparing composite slurry II by using a support; coating the composite slurry II on the surface of the anode catalyst layer, and drying by adopting a second drying process; coating the cathode catalyst slurry on the other side of the proton exchange membrane, and drying to form a gel state layer; providing a support layer; and the membrane is attached to the surface of the gel state layer, and the frequent start-stop resistant membrane electrode of the PEM electrolytic cell is obtained through drying and hot pressing. The problem of membrane electrode damage caused by frequent start and stop of the PEM electrolytic cell is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of PEM electrolytic cell, in particular, to a preparation method of a PEM electrolytic cell resistant to frequent start-stop membrane electrode. BACKGROUND

[0002] With the country vigorously promoting the development of hydrogen energy industry and the continuous expansion of China's wind power, photovoltaic and other clean and green power sources, hydrogen energy will gradually become one of China's important energies. Through wind power and photovoltaic power generation (green electricity), hydrogen production will gradually replace coal chemical industry and become the main way to obtain hydrogen energy. Green hydrogen production, as an important development direction of China's hydrogen energy industry, on the one hand, meets the country's "clean and low-carbon" requirements for the hydrogen energy industry, and on the other hand, hydrogen energy has great advantages in large-scale energy storage and flexible power regulation, promoting the development of new energy. Since green hydrogen production in China is still in the "pilot" stage, some demonstration projects are sporadically distributed in China, and different technical routes are not yet fully mature, and scale benefits have not yet been realized.

[0003] PEM is the abbreviation of proton exchange membrane water electrolysis technology. Unlike traditional alkaline water hydrogen production technology, PEM hydrogen production technology uses proton exchange membrane as solid electrolyte, unlike alkaline water electrolysis hydrogen production, which uses pure water as raw material for electrolysis hydrogen production, avoiding potential alkali pollution and corrosion problems. PEM hydrogen production technology has the advantages of high hydrogen purity, high output hydrogen pressure, high running current density, wide load range, fast dynamic response speed, etc. In the PEM electrolytic cell, oxidation reaction occurs at the anode, where water is oxidized to produce oxygen, protons and electrons in the half-reaction, and then the electrons flow to the cathode through the external circuit. Reduction reaction occurs at the cathode, and the protons produced at the anode combine with the electrons from the external circuit to form hydrogen gas.

[0004] PEM electrolyzers can operate at low temperatures and respond more quickly to changes in power supply, making them ideal for integration with variable renewable energy sources such as solar and wind power. In the coupling process with renewable energy, the lifespan of the PEM electrolyzer directly determines the feasibility of cost-reduction pathways for hydrogen production. Current predictions for the lifespan of PEM electrolyzers range from 60,000 to 80,000 hours, but complete empirical data is still lacking. Furthermore, in both prediction and actual testing, many researchers have overlooked the impact of frequent load increases and decreases, as well as start-ups and shutdowns, on the lifespan of electrolyzers. These complex operating conditions can significantly lead to irreversible degradation of core components and materials, thereby drastically shortening the lifespan of PEM electrolyzers. In actual operation, PEM electrolyzers are subject to the combined damage of multiple physical field effects such as mechanical, chemical, and thermal stress. This can lead to puncture or thinning of the proton exchange membrane in the core component, the membrane electrode assembly (MEA), causing hydrogen-oxygen crosstalk and potentially resulting in localized hotspots or even the risk of combustion and explosion. The catalyst layer undergoes grain coarsening, dissolution / migration, and detachment during intense oxidation / reduction reactions, resulting in the permanent loss of active sites. More critically, at the moment of shutdown, when the system no longer forces water splitting, the anode becomes a "mixed potential" electrode. If the hydrogen concentration is sufficiently high, the hydrogen-hydrogen reaction will dominate. This reaction generates electrons, but since there is no external circuit to consume these electrons, the anode potential is pulled down, potentially even below the cathode potential, resulting in "reverse polarity" (cathode potential higher than anode potential). When the anode potential is pulled down (e.g., from +1.6V to +0.8V or even lower), it enters a potential range that is extremely dangerous for the iridium-based catalyst material. Iridium-based catalysts form oxides during catalysis; these oxides are stable at normal high potentials, forming a protective oxide layer. However, when the potential drops to the range of approximately 0.8–1.4 V (relative to the reversible hydrogen electrode), iridium will change from a stable +4 oxidation state to a soluble +3 oxidation state (such as IrO3²). - Iridium ions (Ir³⁺) dissolve into the aqueous phase of the membrane, further forming soluble substances. This leads to permanent loss of the anode catalyst, a reduction in catalytic active sites, and a sharp decline in electrolyzer performance. +These metal ions migrate into the membrane, even reaching the cathode side. They occupy sulfonate sites within the membrane, reducing its proton conductivity and potentially catalyzing the generation of hydroxyl radicals, accelerating the chemical degradation of the polymer membrane, leading to structural damage and a continuous increase in ohmic and concentration overpotentials. Furthermore, in dynamic scenarios involving coupled renewable energy sources, they accelerate the rapid thermal expansion and contraction of the membrane electrode assembly (MEA), which is particularly damaging in electrolyzers where the cathode is only weakly supported. Especially during frequent start-ups and shutdowns, the high water flow at the anode and the instantaneous pressure increase during rapid anode startup cause the MEA to directly compress the cathode carbon cloth or paper, resulting in the MEA becoming embedded in the cathode flow field, hindering mass transfer and reducing contact. This leads to a rapid voltage increase and may cause widespread hotspot formation, posing an explosion risk.

[0005] Currently, many studies address the issue of frequent start-ups and shutdowns in PEM electrolyzers during bioenergy hydrogen production by employing a flow-channel-less cathode design or thicker metal support materials. However, these methods increase manufacturing difficulty and cost, and also increase electrolyzer energy consumption due to the increased contact interface, significantly hindering current low-energy technology development. Current research has not comprehensively addressed the multi-dimensional problems arising from frequent start-ups and shutdowns through material repair and structural optimization. Therefore, proposing a novel composite membrane electrode fabrication method to avoid this problem is urgently needed. Summary of the Invention

[0006] In view of one of the defects in the prior art, the purpose of this application is to provide a method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode.

[0007] This application provides a method for preparing a PEM electrolyzer resistant to frequent start-stop membrane electrode, comprising: Provide composite slurry one; The composite slurry is coated on one side of a proton exchange membrane and dried to obtain a composite layer. An anode catalyst slurry containing a self-healing catalyst material is provided. The anode catalyst slurry is coated on the surface of the composite layer and dried using a first drying process to obtain the anode catalyst layer. Preparation of composite slurry using a support; The composite slurry is coated onto the surface of the anode catalyst layer and dried using a second drying process. A cathode catalyst slurry is provided, and the cathode catalyst slurry is coated on the other side of a proton exchange membrane and dried to form a gel layer. Provide a support layer; The support layer is attached to the surface of the gel layer, and after drying and hot pressing, a PEM electrolytic cell resistant to frequent start-stop membrane electrode is obtained.

[0008] Optionally, the provision of the composite slurry includes: Weigh out the free radical scavenger, hydrogen elimination catalyst, and sulfonated graphene oxide separately, and wet them with deionized water; Add binder, proton exchange membrane self-healing material and organic solvent, heat and stir evenly to obtain composite slurry one.

[0009] Optionally, the composite slurry is coated on one side of the proton exchange membrane and dried to obtain a composite layer, wherein the coating speed of the composite slurry is 1-3 m / min, the wet coating thickness is 200-400 μm, and the drying temperature is 70-90℃.

[0010] Optionally, the provision of the anode catalyst slurry containing a catalyst self-healing material includes: Weigh out the anode catalyst and the catalyst self-healing material, add deionized water, and then add the binder to obtain a mixed solution; Disperse the mixed solution; An organic solvent is added, and the mixture is homogeneously dispersed to obtain an anode catalyst slurry. The parameters of the first drying process are: drying temperature 30-50℃, drying time 5-10min.

[0011] Optionally, the preparation of composite slurry II using a support includes: Weigh the support, add the emulsion and binder, then add deionized water and alcohol solvent, and disperse evenly to obtain composite slurry II.

[0012] Optionally, the composite slurry II is coated onto the surface of the anode catalyst layer and dried using a second drying process, wherein: the coating speed of the composite slurry II is 1-3 m / min, and the wet coating thickness is 400-800 μm; the parameters of the second drying process are: drying temperature 70-90℃, and drying time 20-40 min.

[0013] Optionally, the cathode catalyst slurry is provided, wherein: The cathode catalyst slurry comprises a platinum-carbon catalyst, a binder, deionized water, and an alcohol solvent, wherein the mass percentage of platinum in the platinum-carbon catalyst is 40-70%.

[0014] Optionally, the cathode catalyst slurry is coated on the other side of the proton exchange membrane and dried to form a gel layer, wherein: the coating speed of the cathode catalyst slurry is 1-3 m / min, the wet coating thickness is 400-600 μm, the drying temperature is 40-60℃, and the drying time is 3-7 min.

[0015] Optionally, the support layer is provided, wherein the support layer is any one of porous titanium mesh, titanium fiber felt, and porous titanium plate.

[0016] Optionally, the support layer is attached to the surface of the gel layer, and after drying and hot pressing, a PEM electrolytic cell resistant to frequent start-stop membrane electrode is obtained, wherein: the drying temperature is 60-80℃, the hot pressing temperature is 100-120℃, and the hot pressing pressure is 0.5-1.5MPa.

[0017] The method for preparing a PEM electrolyzer resistant to frequent start-stop cycles provided in this application addresses the risk of hydrogen permeation from the cathode to the anode during frequent start-stop cycles by coating the anode with a composite layer, effectively solving the hydrogen-oxygen crosstalk problem and promptly eliminating any hydrogen permeation into the anode. The use of an anode catalyst material containing self-healing catalyst material prevents catalyst dissolution and detachment during frequent start-stop cycles. Through the coordinated process steps, the double support layer and catalyst layer form a unified whole, reducing contact resistance and preventing the support layer from oxidizing when exposed to air. The support layer also effectively protects the cathode catalyst layer, cathode gas diffusion layer, and proton exchange membrane from stretching and cutting damage, meeting the requirements for long-term operation. This application features a simple manufacturing process that effectively solves the multi-dimensional problems of hydrogen-oxygen crosstalk during frequent start-stop cycles in PEM electrolyzers, hydrogen entering the anode side from the cathode after shutdown, and high contact resistance causing membrane electrode damage.

[0018] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0019] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating a method for preparing a PEM electrolyzer resistant to frequent start-stop membrane electrode according to an exemplary embodiment; Figure 2 The morphology of the membrane electrode in Application Examples 1-3 and Comparative Example 1 is shown. Figure 3 This is a morphology diagram of the membrane electrode in Comparative Example 2; Figure 4 This is a morphology diagram of the membrane electrode in Comparative Example 3; Figure 5 The image shows the morphology of the membrane electrode in Comparative Example 4. Figure 6 The image shows the morphology of the membrane electrode in Comparative Example 5. Figure 7 This is a morphology diagram of the membrane electrode in Comparative Example 6. Detailed Implementation

[0020] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0021] Existing methods for preparing membrane electrodes for PEM electrolyzers cannot effectively address the damage issues caused by frequent load increases and decreases, as well as start-ups and shutdowns of the electrolyzer, such as hydrogen-oxygen crosstalk, reduction of catalytic active sites, and high contact resistance. To address these problems, this application provides a method for preparing a membrane electrode for PEM electrolyzers that is resistant to frequent start-ups and shutdowns, thereby resolving these issues.

[0022] Reference Figure 1 As shown in one embodiment of this application, the preparation method of the PEM electrolyzer resistant to frequent start-stop membrane electrode includes the following steps: S1. Provide composite slurry; S2. The composite slurry is coated on one side of the proton exchange membrane and dried to obtain the composite layer. S3. Provide an anode catalyst slurry containing a catalyst self-healing material, coat the anode catalyst slurry onto the surface of the composite layer, and dry it using a first drying process to obtain the anode catalyst layer; S4. Preparation of composite slurry II using a support; S5. The composite slurry is coated onto the surface of the anode catalyst layer and dried using the second drying process. S6. Provide cathode catalyst slurry, coat the cathode catalyst slurry on the other side of the proton exchange membrane, and dry to form a gel layer; S7. Provides a support layer; S8. The support layer is attached to the surface of the gel layer, and after drying and hot pressing, a PEM electrolytic cell resistant to frequent start-stop membrane electrode is obtained.

[0023] The method for preparing a PEM electrolyzer resistant to frequent start-stop cycles provided in this application addresses the risk of hydrogen permeation from the cathode to the anode during frequent start-stop cycles by coating the anode with a composite layer, effectively solving the hydrogen-oxygen crosstalk problem and promptly eliminating hydrogen permeation into the anode. The use of an anode catalyst material containing self-healing catalyst material prevents catalyst dissolution and detachment during frequent start-stop cycles. Through the coordinated process steps, a novel membrane electrode with bidirectional support is obtained. The double support layer and catalyst layer form a unified whole, reducing contact resistance and preventing the support layer from oxidizing when exposed to air. The support layer also effectively protects the cathode catalyst layer, cathode gas diffusion layer, and proton exchange membrane from stretching and cutting damage, meeting the requirements for long-term operation. This application features a simple manufacturing process that effectively solves the multi-dimensional problems of hydrogen-oxygen crosstalk during frequent start-stop cycles in PEM electrolyzers, hydrogen entering the anode side from the cathode after shutdown, and high contact resistance causing membrane electrode damage, thus contributing to reduced energy consumption in the electrolyzer.

[0024] In order to provide a slurry with both hydrogen removal and barrier functions, in some specific embodiments of this application, S1, providing a composite slurry may include: S11. Weigh out the free radical scavenger, hydrogen elimination catalyst, and sulfonated graphene oxide respectively, and wet them with deionized water. S12. Add binder, proton exchange membrane self-healing material and organic solvent, heat and stir evenly to obtain composite slurry one.

[0025] Specifically, the free radical scavenger is any one of nano-cerium dioxide, nano-manganese dioxide, and nano-zirconia, with a nanoparticle size of 2-7 nm. The hydrogen elimination catalyst is nano-platinum black or nano-ruthenium, with a nanoparticle size of 4-10 nm. The sulfonated graphene oxide has a particle size of 200-500 nm. The proton exchange membrane self-healing material is any one of sulfonated polyvinyl alcohol, sulfonated graphene, and a mixture of perfluorosulfonic acid resin. The binder is a 5-15% solution of short-side-chain perfluorosulfonic acid resin; the organic solvent is any one of ethanol, isopropanol, and n-propanol. The mass ratio of the free radical scavenger, hydrogen elimination catalyst, sulfonated graphene oxide, proton exchange membrane self-healing material, deionized water, binder, and organic solvent is 1:(5-10):(0.2-0.4):(3-7):(15-30):(25-40):(300-500).

[0026] For example, the heating and stirring temperature is 40-60℃, and the stirring time is 24-48h.

[0027] In order to form a composite layer on one side of the proton exchange membrane, in some specific embodiments of this application, in step S2, the coating speed of the composite slurry is 1-3 m / min, the wet coating thickness is 200-400 μm, and the drying temperature is 70-90℃.

[0028] In the embodiments described above, during the fabrication of the membrane electrode, a composite layer containing short-chain perfluorosulfonic acid resin, a free radical scavenger, a proton exchange membrane self-healing material, and a hydrogen removal catalyst is coated on the anode. On the one hand, due to its crystalline structure, the short-chain perfluorosulfonic acid resin forms a resin layer with excellent hydrogen barrier capabilities, preventing the risk of hydrogen from the cathode permeating into the anode during frequent start-ups and shutdowns, effectively solving the hydrogen-oxygen crosstalk problem. On the other hand, after shutdown, a large amount of hydrogen from the cathode will instantly enter the anode side due to the concentration difference, causing a hydrogen oxidation reaction at the anode, which may generate a large number of free radicals, thereby damaging the proton exchange membrane and the binder in the catalyst layer. Therefore, the free radical scavenger and hydrogen removal catalyst in the composite layer, located adjacent to the proton exchange membrane, promptly eliminate the hydrogen permeating into the anode, avoiding the occurrence of risks.

[0029] The proton exchange membrane repair material added to the composite layer can solve problems such as cracking, pinholes, and thinning caused by continuous impact during frequent start-ups and shutdowns of the proton exchange membrane. These polymer materials and the hydroxyl groups in sulfonated graphene oxide easily form hydrogen bond networks, or are combined with a small amount of dynamically covalent monomers, which can endow it with self-healing ability. In the humid environment of the electrolyzer, the dynamic recombination of hydrogen bonds can help repair the micro-cracks in the proton exchange membrane, avoiding the risk of proton exchange membrane rupture or perforation.

[0030] To effectively prevent the reduction of active sites on the anode catalyst, in some specific embodiments of this application, in step S3, an anode catalyst slurry containing a catalyst self-healing material is provided, including: S31. Weigh the anode catalyst and the catalyst self-healing material and place them in a container. Add deionized water and then add the binder to obtain a mixed solution. S32. Disperse the mixed solution in a planetary stirrer for 10-30 minutes; S33. Add organic solvent and homogenize and disperse 3-5 times using a homogenizer with a pressure of 3-5 MPa to obtain the anode catalyst slurry.

[0031] Specifically, the anode catalyst slurry includes an anode catalyst, a catalyst repair agent, a binder, deionized water, and an organic solvent. The anode catalyst is any one of iridium black, iridium oxide, ruthenium oxide, or platinum-iridium composite catalysts with a nanoparticle size of 7-15 nm. The catalyst repair agent is any one of iridium-doped manganese dioxide, sulfonated manganese dioxide, or iridium-doped cobalt-manganese oxide, with a nanoparticle size of 20-40 nm. The binder is a 5-20% solution of long-side-chain perfluorosulfonic acid resin. The organic solvent is a mixture of alcohol solvents and high-boiling-point solvents, wherein the alcohol solvent is any one of ethanol, isopropanol, or n-propanol, and the high-boiling-point organic solvent is any one of N,N-dimethylpyrrolidone, N,N-diformamide, or N,N-diacetamide. The mass ratio of the anode catalyst, catalyst self-healing material, binder, deionized water, alcohol solvent, and high-boiling-point organic solvent is 1:(0.1-0.3):(10-25):(5-10):(100-180):(2-5).

[0032] For example, in S3, the coating parameters are: coating speed 1-3 m / min, coating wet thickness 400-600 μm. The parameters for the first drying process are: drying temperature 30-50℃, drying time 5-10 min.

[0033] In the embodiments described above, a self-healing material with catalytic activity was added during the preparation of the anode catalyst layer. The "self-healing" capability of this material is essentially a "dynamic dissolution-redeposition" and "surface electrochemical reconstruction" that occur under harsh anode oxygen evolution conditions. By adding this material, the inevitable "reconstruction" process is steered in a direction that is conducive to maintaining or regenerating active sites, thus preventing the complete collapse of the anode catalyst and the dissolution and detachment of the catalyst layer. On the other hand, the catalyst-based repair material easily forms complexes with polymers such as perfluorosulfonic acid resins. These complexes can encapsulate the catalyst particles, reducing the impact of mechanical vibrations on the catalyst during start-up and shutdown, and minimizing detachment. Furthermore, they can resist free radicals generated during the reaction, preventing the catalyst structure from being damaged, thereby reducing abnormal grain growth and dissolution.

[0034] In order to form a support layer on the anode catalyst layer side of the proton exchange membrane, in some specific embodiments of this application, S4, preparing composite slurry II using the support may include: weighing the support, adding emulsion and binder, then adding deionized water and alcohol solvent, and dispersing evenly to obtain composite slurry II.

[0035] Specifically, the support is either titanium fiber or titanium nanotube with a length of 8-18μm and a diameter of 100-200nm. The pretreated support is then cleaned and formulated into a composite slurry.

[0036] The pretreatment steps for the support are as follows: A1. Clean the support with deionized water using ultrasonic cleaning for 30-50 minutes; A2. Place the support after ultrasonic cleaning with deionized water into ethanol and continue ultrasonic cleaning for 10-30 minutes; then rinse it with deionized water. A3. Prepare a formic acid solution with a mass concentration of 3-5 wt.%, immerse the support treated in step A2 in the solution and heat and ultrasonically clean it for 20-40 minutes at a temperature of 40-60℃. Then rinse it with deionized water and dry it in an inert atmosphere to obtain the pretreated support. The inert atmosphere is any one of nitrogen, helium, or argon.

[0037] The preparation of composite slurry II is as follows: Weigh the pretreated support, add the emulsion and binder, then add deionized water and alcohol solvent, and disperse evenly to obtain composite slurry II; wherein the emulsion is 10-20% polytetrafluoroethylene emulsion, the binder is 5-20% long side chain perfluorosulfonic acid resin solution, and the alcohol solvent is either ethanol or isopropanol; the mass ratio of the support, emulsion, binder, deionized water and alcohol solvent is 1:(3-6):(15-50):(100-150):(100-150).

[0038] In order to obtain a semi-finished membrane electrode, in some specific embodiments of this application, in step S5, the coating speed of composite slurry II is 1-3 m / min, and the wet coating thickness is 400-800 μm; the parameters of the second drying process are: drying temperature 70-90℃, drying time 20-40 min.

[0039] In the embodiments described above, after the anode catalyst layer is dried using the first drying process to form a semi-fluid state, a layer of composite slurry containing a support is applied to the surface of the semi-fluid state, which allows the support layer and the catalyst layer to form a whole. Furthermore, considering that in the actual electrolytic cell manufacturing process, a thin titanium felt is used as a diffusion layer for the anode to save costs and also serves to support the membrane electrode, but there is still a risk of weak support under high cathode operating conditions, a support layer is prepared on the anode catalyst layer of the membrane electrode, and this is done in a semi-fluid state. Considering that in the semi-fluid state, under no pressure or low pressure, the felt of the support layer will not puncture the coating or the proton exchange membrane, and under the action of the self-healing material (heat drying), the damaged or punctured coating begins to self-repair, thereby automatically achieving a tight and secure connection between the support layer and the coating. After heat treatment and complete drying, further treatment such as hot pressing is performed to ensure the interlayer bonding strength. In actual operation, this effectively increases the contact conductive surface, promotes rapid electron conduction, reduces contact resistance, and improves performance.

[0040] It should be noted that in the current preparation method, the anode titanium felt is a separate component that is stacked during assembly. It serves two purposes: first, to support the film electrode, and second, to act as a current collector (anode gas diffusion layer).

[0041] In order to achieve the preparation of the cathode catalyst layer, in some specific embodiments of this application, in step S6, the cathode catalyst slurry includes a platinum-carbon catalyst, a binder, deionized water and an alcohol solvent, and the mass percentage of platinum in the platinum-carbon catalyst is 40-70%.

[0042] Specifically, the binder in the catalyst slurry is a 5-20% long-side-chain perfluorosulfonic acid resin solution; the alcohol solvent is any one of ethanol, isopropanol, and n-propanol; the mass ratio of platinum carbon catalyst, binder, deionized water and alcohol solvent is 1:(10-30):(5-10):(120-150).

[0043] In order to form a gel-like cathode catalyst layer, in some specific embodiments of this application, in step S6, the coating speed of the cathode catalyst slurry is 1-3 m / min, the wet coating thickness is 400-600 μm, the drying temperature is 40-60℃, and the drying time is 3-7 min.

[0044] In order to provide support for the cathode catalyst layer side of the proton exchange membrane, in some specific embodiments of this application, in step S7, the support layer is any one of porous titanium mesh, titanium fiber felt and porous titanium plate.

[0045] Specifically, the support layer is any one of the following: a porous titanium mesh with a thickness of 0.2-0.4 mm, a titanium fiber felt with a porosity of 50-80% and a thickness of 0.2-0.4 mm, or a porous titanium plate with a thickness of 0.08-0.2 mm and a porosity of 30-55%. The support layer undergoes pretreatment, and the pretreatment steps are as follows: B1. Place the support layer in a processor containing fine sand and sandblast for 5-10 minutes; B2. Place the treated support layer in an alcohol solvent and ultrasonically clean it for 20-40 minutes. B3. Place the cleaned support layer in a formic acid solution with a mass concentration of 5-8 wt.% and heat for 30-60 minutes at a temperature of 50-70°C. Then remove it, rinse off the residual formic acid solution on the surface with deionized water, and dry it in an inert atmosphere for later use. The inert atmosphere can be any one of nitrogen, helium, or argon.

[0046] In the above embodiments of this application, deionized water, ethanol and acidic solutions are used for cleaning during the pretreatment of the support and support layer to ensure that the surface is clean, effectively remove surface dust, oil and surface oxides, reduce the resistance and improve the overall performance of the electrolytic cell.

[0047] In order to prepare the double support layer and the catalyst layer into a whole, in some specific embodiments of this application, in step S8, the drying temperature is 60-80°C, the hot pressing temperature is 100-120°C, and the hot pressing pressure is 0.5-1.5 MPa.

[0048] Specifically, in this step, by setting the drying and hot pressing parameters, excess solvent is first evaporated, and then the multilayer composite structure of the membrane electrode is more tightly bonded together under the hot pressing temperature and pressure, avoiding defects such as bubbles. In particular, during the hot pressing process, the binder is in a slightly molten state, which is more conducive to the bonding of the catalyst and the support layer.

[0049] In the above embodiments of this application, when preparing the cathode catalyst layer, a support layer is attached to the surface of the catalyst layer in a gel state. Before attachment, the support layer is sandblasted. The fine burrs on the surface of the support layer are polished by the high-speed impact of fine sand, so as to avoid puncturing the proton exchange membrane. In addition, the high-speed jet impact on the surface of the support layer achieves the purpose of cleaning, removing the oxide layer and strengthening, thereby improving the bonding force between the support layer and the cathode catalyst layer.

[0050] The treated support layer and cathode catalyst layer are integrated to reduce contact resistance and avoid the risk of oxidation of the support layer when exposed to air. In addition, the presence of the support layer can prevent the membrane electrode from being compressed and deformed towards the cathode flow field due to the frequent transient high pressure at the anode when the anode water content is much higher than that at the cathode during frequent start-up and shutdown. It can effectively protect the cathode catalyst layer, cathode gas diffusion layer and proton exchange membrane from stretching and cutting damage, and meet the requirements of long-term operation.

[0051] It should be noted that the parameter settings in the above steps of this application take into account the high temperature resistance of the material, the selection of solvent, the evaporation and drying characteristics, the pressure resistance of the catalyst layer and the proton exchange membrane, etc., thereby effectively solving the problem of membrane electrode damage caused by frequent start-up and shutdown of PEM electrolyzer.

[0052] The preferred features in the above embodiments can be used individually in any embodiment, or in any combination thereof, provided they do not conflict with each other. Furthermore, parts not described in detail in the embodiments can be implemented using existing technologies.

[0053] The following examples and comparative examples will be used to further illustrate this application in order to better understand the above-mentioned technical solutions. It should be understood that the following are only some examples and are not intended to limit this application.

[0054] Application Example 1: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the anode catalyst layer in a semi-fluid state using a first drying process with a drying temperature of 30℃ and a drying time of 10 min. 6. Weigh 20g of titanium fiber with a length of 8μm and a diameter of 100nm, and ultrasonically clean it in deionized water for 50min; take it out and continue to ultrasonically clean it in ethanol for 30min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 6g of 99% pure formic acid, dissolve it in 194g of deionized water to prepare a 3% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 40℃, ultrasonically clean it for 40 minutes, then clean it with deionized water and dry it in a nitrogen atmosphere for later use. 8. Weigh 10g of titanium fiber treated in step 7, add 30g of 20% polytetrafluoroethylene emulsion and 500g of 5% long side chain perfluorosulfonic acid resin solution, then add 1000g of deionized water and 1000g of ethanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 400 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 5. Dry it under the second drying process at a temperature of 70℃ and a time of 40 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long-side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to 3 m / min and 600 μm wet coating thickness, coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode, and dry it at 60°C for 3 min to form a gel layer. 12. Take a porous titanium mesh with a thickness of 0.2 mm that is the same size as the cathode gel layer coated in step 11, place it in a processor containing fine sand and sandblast it for 5 min; then take it out and place it in ethanol for ultrasonic cleaning for 20 min; then place it in a solution containing 5% formic acid and soak it at 50°C for 60 min, take it out and rinse it with plenty of deionized water, and dry it in a nitrogen atmosphere for later use. 13. The support layer after the pretreatment in step 12 is attached to the surface of the gel layer prepared in step 11, dried at 60°C, and hot-pressed at 100°C and 1.5MPa to obtain a membrane electrode for PEM electrolysis cell that is resistant to frequent start-stop.

[0055] Application Example 2: 1. Weigh 5g of 7nm nano manganese dioxide, 50g of 10nm nano ruthenium, and 2g of 500nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 125g of 15% short-side-chain perfluorosulfonic acid resin solution and 35g of a mixture of sulfonated graphene oxide and perfluorosulfonic acid resin, and finally add 2500g of n-propanol. After mixing, heat to 60℃ and stir continuously for 24 hours to obtain a composite slurry for later use. 3. Set the coating speed to 1 m / min and the wet coating thickness to 400 μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 90°C to obtain a proton exchange membrane with a composite layer. 4. Weigh 10g of 15nm iridium oxide catalyst and 3g of 40nm iridium-doped manganese dioxide, add 100g of deionized water to fully wet, then add 100g of 20% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 30min; then weigh 1800g of n-propanol and 50g of N,N-dicarboxamide, mix them, place them in a homogenizer, and disperse them 3 times under a pressure of 5MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 1 m / min and the wet coating thickness to 600 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the anode catalyst layer in a semi-fluid state using a first drying process with a drying temperature of 50℃ and a drying time of 5 min. 6. Weigh 10g of titanium fiber with a length of 18μm and a diameter of 200nm, and place it in deionized water for ultrasonic cleaning for 30min; take it out and continue to place it in ethanol for ultrasonic cleaning for 10min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 10g of 99% pure formic acid, dissolve it in 190g of deionized water to prepare a 5% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 60℃, ultrasonically clean it for 20 minutes, then clean it with deionized water and dry it in a helium atmosphere for later use. 8. Weigh 5g of titanium fiber treated in step 7, add 30g of 10% polytetrafluoroethylene emulsion and 75g of 20% long side chain perfluorosulfonic acid resin solution, then add 750g of deionized water and 750g of isopropanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 1 m / min and a wet coating thickness of 800 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 5. Dry it under the second drying process at a temperature of 90℃ and a time of 20 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 70% platinum-carbon catalyst, add 50g of deionized water to fully wet it, then add 100g of 20% long side-chain perfluorosulfonic acid resin solution and 1500g of n-propanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to 3 m / min and 400 μm wet coating thickness, and coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode. Dry it at 40°C for 7 min to form a gel layer. 12. Take a titanium fiber felt with a thickness of 0.2 mm and a porosity of 50%, which is the same as the cathode gel layer coated in step 11. Place it in a processor containing fine sand and sandblast it for 10 min. Then take it out and place it in ethanol for ultrasonic cleaning for 40 min. Next, place it in a solution containing 8% formic acid and soak it at 70°C for 30 min. Take it out and rinse it with plenty of deionized water. Then dry it in a helium atmosphere for later use. 13. The support layer after the pretreatment in step 12 is attached to the surface of the gel layer prepared in step 11, dried at 80°C, and hot-pressed at 120°C and 0.5MPa to obtain a membrane electrode for PEM electrolysis cell that is resistant to frequent start-stop.

[0056] Application Example 3: 1. Weigh 10g of 5nm nano-zirconia, 80g of 8nm platinum black and 3g of 300nm sulfonated graphene oxide and add them to a container. Add 250g of deionized water to fully wet the material. 2. Add 300g of 10% short-side-chain perfluorosulfonic acid resin solution and 50g of sulfonated polyvinyl alcohol, and finally add 4000g of ethanol. After mixing, heat to 50℃ and stir continuously for 36 hours to obtain a composite slurry for later use. 3. Set the coating speed to 2m / min and the wet coating thickness to 300μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 80℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 10nm ruthenium oxide catalyst and 1g of 30nm iridium-doped cobalt manganese oxide, add 40g of deionized water to fully wet, then add 75g of 15% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 20min; then weigh 750g of ethanol and 20g of N,N-diacetamide, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 2 m / min and the wet coating thickness to 500 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the anode catalyst layer in a semi-fluid state using a first drying process with a drying temperature of 40℃ and a drying time of 8 min. 6. Weigh 20g of titanium nanotubes with a length of 8μm and a diameter of 100nm, and place them in deionized water for ultrasonic cleaning for 40min; remove them and continue ultrasonic cleaning in ethanol for 20min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 8g of 99% pure formic acid, dissolve it in 192g of deionized water to prepare a 4% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 50℃, ultrasonically clean it for 30 minutes, then clean it with deionized water and dry it in an argon atmosphere for later use. 8. Weigh 10g of titanium nanotubes treated in step 7, add 45g of 15% polytetrafluoroethylene emulsion and 300g of 10% long side chain perfluorosulfonic acid resin solution, then add 1200g of deionized water and 1200g of ethanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 2 m / min and a wet coating thickness of 600 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 5. Dry it under the second drying process at a temperature of 80℃ and a time of 30 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 60% platinum-carbon catalyst, add 80g of deionized water to fully wet it, then add 200g of 10% long-side-chain perfluorosulfonic acid resin solution and 1300g of ethanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to a coating speed of 2 m / min and a wet coating thickness of 500 μm, and coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode. Dry it at 50°C for 5 min to form a gel layer. 12. Take a porous titanium plate with a thickness of 0.1 mm and a porosity of 30%, which is the same as the cathode gel layer coated in step 11. Place it in a processor containing fine sand for sandblasting for 7 min. Then take it out and place it in ethanol for ultrasonic cleaning for 30 min. Next, place it in a solution containing 6% formic acid and soak it at 60°C for 40 min. Take it out and rinse it with plenty of deionized water. Then dry it in an argon atmosphere for later use. 13. The support layer after the pretreatment in step 12 is attached to the surface of the gel layer prepared in step 11, dried at 70°C, and hot-pressed at 110°C and 1.0 MPa to obtain a membrane electrode for PEM electrolysis cell that is resistant to frequent start-stop.

[0057] Comparative Example 1: In this comparative example, the fabrication process of the membrane electrode does not involve a composite layer. The specific steps are as follows: 1. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 2. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm, and coat the anode catalyst slurry prepared in step 4 onto the surface of the proton exchange membrane; use the first drying process with a drying temperature of 30℃ and a drying time of 10 min to dry the anode catalyst layer in a semi-fluid state. 3. Weigh 20g of titanium fiber with a length of 8μm and a diameter of 100nm, and place it in deionized water for ultrasonic cleaning for 50min; take it out and continue to place it in ethanol for ultrasonic cleaning for 30min; then rinse off the excess ethanol with plenty of deionized water. 4. Weigh 6g of 99% pure formic acid, dissolve it in 194g of deionized water to prepare a 3% formic acid solution, then place the titanium fiber cleaned in step 3 into the formic acid solution, heat it to 40℃, ultrasonically clean it for 40 minutes, then clean it with deionized water and dry it in a nitrogen atmosphere for later use. 5. Weigh 10g of titanium fiber treated in step 4, add 30g of 20% polytetrafluoroethylene emulsion and 500g of 5% long side chain perfluorosulfonic acid resin solution, then add 1000g of deionized water and 1000g of ethanol, and disperse evenly to obtain composite slurry. 6. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 400 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 2. Dry it at a temperature of 70℃ for 40 min to obtain a semi-finished membrane electrode. 7. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 8. Set the coating parameters to 3 m / min and 600 μm wet coating thickness, and coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode. Dry it at 60°C for 3 min to form a gel layer. 9. Take a porous titanium mesh with a thickness of 0.2 mm that is the same size as the cathode gel layer coated in step 8, place it in a processor containing fine sand and sandblast it for 5 min; then take it out and place it in ethanol for ultrasonic cleaning for 20 min; then place it in a solution containing 5% formic acid and soak it at 50°C for 60 min, take it out and rinse it with plenty of deionized water, and dry it in a nitrogen atmosphere for later use. 10. The support layer after pretreatment in step 9 is attached to the surface of the gel layer prepared in step 11, dried at 60°C, and hot-pressed at 100°C and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0058] Comparative Example 2: The comparative example anode catalyst slurry did not contain catalyst repair agent. The specific steps are as follows: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst, add 25g of deionized water to fully wet it, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the anode catalyst layer in a semi-fluid state using a first drying process with a drying temperature of 30℃ and a drying time of 10 min. 6. Weigh 20g of titanium fiber with a length of 8μm and a diameter of 100nm, and ultrasonically clean it in deionized water for 50min; take it out and continue to ultrasonically clean it in ethanol for 30min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 6g of 99% pure formic acid, dissolve it in 194g of deionized water to prepare a 3% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 40℃, ultrasonically clean it for 40 minutes, then clean it with deionized water and dry it in a nitrogen atmosphere for later use. 8. Weigh 10g of titanium fiber treated in step 7, add 30g of 20% polytetrafluoroethylene emulsion and 500g of 5% long side chain perfluorosulfonic acid resin solution, then add 1000g of deionized water and 1000g of ethanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 400 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 5. Dry it under the second drying process at a temperature of 70℃ and a time of 40 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long-side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to 3 m / min and 600 μm wet coating thickness, coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode, and dry it at 60°C for 3 min to form a gel layer. 12. Take a porous titanium mesh with a thickness of 0.2 mm that is the same size as the cathode gel layer coated in step 11, place it in a processor containing fine sand and sandblast it for 5 min; then take it out and place it in ethanol for ultrasonic cleaning for 20 min; then place it in a solution containing 5% formic acid and soak it at 50°C for 60 min, take it out and rinse it with plenty of deionized water, and dry it in a nitrogen atmosphere for later use. 13. The support layer after pretreatment in step 12 is attached to the surface of the gel layer prepared in step 11, dried at 60°C, and hot-pressed at 100°C and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0059] Comparative Example 3: The fabrication of this comparative membrane electrode does not include a support layer above the anode catalyst layer. The specific steps are as follows: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the membrane using the first drying process at a drying temperature of 30℃ and a drying time of 10 min to obtain the semi-finished membrane electrode. 6. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 7. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 600 μm, and coat the cathode catalyst slurry prepared in step 6 onto the other side of the semi-finished membrane electrode. Dry it at 60°C for 3 min to form a gel layer. 8. Take a porous titanium mesh with a thickness of 0.2 mm that is the same size as the cathode gel layer coated in step 7, place it in a processor containing fine sand and sandblast it for 5 min; then take it out and place it in ethanol for ultrasonic cleaning for 20 min; then place it in a solution containing 5% formic acid and soak it at 50°C for 60 min, take it out and rinse it with plenty of deionized water, and dry it in a nitrogen atmosphere for later use. 9. The pretreated support layer from step 8 is bonded to the surface of the gel layer prepared in step 11, dried at 60°C, and hot-pressed at 100°C and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0060] Comparative Example 4: The fabrication of this comparative film electrode does not involve a cathode support; the specific steps are as follows: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the anode catalyst layer in a semi-fluid state using a first drying process with a drying temperature of 30℃ and a drying time of 10 min. 6. Weigh 20g of titanium fiber with a length of 8μm and a diameter of 100nm, and ultrasonically clean it in deionized water for 50min; take it out and continue to ultrasonically clean it in ethanol for 30min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 6g of 99% pure formic acid, dissolve it in 194g of deionized water to prepare a 3% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 40℃, ultrasonically clean it for 40 minutes, then clean it with deionized water and dry it in a nitrogen atmosphere for later use. 8. Weigh 10g of titanium fiber treated in step 7, add 30g of 20% polytetrafluoroethylene emulsion and 500g of 5% long side chain perfluorosulfonic acid resin solution, then add 1000g of deionized water and 1000g of ethanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 400 μm, and coat the composite slurry prepared in step 8 onto the surface of the semi-fluid anode catalyst layer prepared in step 5. Dry it under the second drying process at a temperature of 70℃ and a time of 40 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long-side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to 3 m / min and 600 μm wet coating thickness, coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode, and dry it at 60°C for 3 min to form a gel layer. 12. The electrode is dried at 60℃ and hot-pressed at 100℃ and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0061] Comparative Example 5: The fabrication of this comparative film electrode does not include an anode support layer and a cathode support. The specific steps are as follows: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry the membrane using the first drying process at a drying temperature of 30℃ and a drying time of 10 min to obtain the semi-finished membrane electrode. 6. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 7. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 600 μm, and coat the cathode catalyst slurry prepared in step 6 onto the other side of the semi-finished membrane electrode. Dry it at 60°C for 3 min to form a gel layer. 8. The electrode is dried at 60℃ and hot-pressed at 100℃ and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0062] Comparative Example 6: In the preparation of the membrane electrode in this comparative example, the anode support layer and the cathode support are applied after the coating has dried. The specific steps are as follows: 1. Weigh 10g of 2nm nano-cerium dioxide, 50g of 4nm platinum black and 2g of 200nm sulfonated graphene oxide and add them to a container. Add 150g of deionized water to fully wet the mixture. 2. Add 400g of 5% short-side-chain perfluorosulfonic acid resin solution and 30g of sulfonated polyvinyl alcohol, and finally add 3000g of isopropanol. After mixing, heat to 40℃ and stir continuously for 48h to obtain composite slurry for later use. 3. Set the coating speed to 3m / min and the wet coating thickness to 200μm. Coat the composite slurry prepared in step 2 onto one side of the proton exchange membrane and dry it at 70℃ to obtain a proton exchange membrane with a composite layer. 4. Weigh 5g of 7nm iridium black catalyst and 0.5g of 20nm sulfonated manganese dioxide, add 25g of deionized water to fully wet, then add 125g of 5% long-side-chain perfluorosulfonic acid resin, and then place it in a planetary stirrer to disperse for 10min; then weigh 500g of isopropanol and 10g of N,N-dimethylpyrrolidone, mix them, place them in a homogenizer, and disperse them 5 times under a pressure of 3MPa to obtain the anode catalyst slurry; 5. Set the coating parameters to 3 m / min and the wet coating thickness to 400 μm. Coat the anode catalyst slurry prepared in step 4 onto the composite layer on the surface of the proton exchange membrane prepared in step 3. Dry thoroughly to obtain the anode catalyst layer. 6. Weigh 20g of titanium fiber with a length of 8μm and a diameter of 100nm, and ultrasonically clean it in deionized water for 50min; take it out and continue to ultrasonically clean it in ethanol for 30min; then rinse off the excess ethanol with plenty of deionized water. 7. Weigh 6g of 99% pure formic acid, dissolve it in 194g of deionized water to prepare a 3% formic acid solution, then place the titanium fiber cleaned in step 6 into the formic acid solution, heat it to 40℃, ultrasonically clean it for 40 minutes, then clean it with deionized water and dry it in a nitrogen atmosphere for later use. 8. Weigh 10g of titanium fiber treated in step 7, add 30g of 20% polytetrafluoroethylene emulsion and 500g of 5% long side chain perfluorosulfonic acid resin solution, then add 1000g of deionized water and 1000g of ethanol, and disperse evenly to obtain composite slurry II. 9. Set the coating parameters to a coating speed of 3 m / min and a wet coating thickness of 400 μm, and coat the composite slurry prepared in step 8 onto the surface of the anode catalyst layer prepared in step 5. Dry it in a second drying process at a temperature of 70℃ for 40 min to obtain a semi-finished membrane electrode. 10. Weigh 10g of 40% platinum-carbon catalyst, add 100g of deionized water to fully wet it, then add 300g of 5% long-side-chain perfluorosulfonic acid resin solution and 1200g of isopropanol, stir and disperse evenly to obtain cathode catalyst slurry. 11. Set the coating parameters to 3 m / min and 600 μm wet coating thickness, and coat the cathode catalyst slurry prepared in step 10 onto the other side of the semi-finished membrane electrode. Dry it thoroughly at 60°C to form a cathode catalyst layer. 12. Take a porous titanium mesh with a thickness of 0.2 mm that is the same size as the cathode catalyst layer coated in step 11, place it in a processor containing fine sand and sandblast it for 5 min; then take it out and place it in ethanol for ultrasonic cleaning for 20 min; then place it in a solution containing 5% formic acid and soak it at 50°C for 60 min, take it out and rinse it with a large amount of deionized water, and dry it under a nitrogen atmosphere for later use. 13. The support layer after pretreatment in step 12 is attached to the surface of the cathode catalyst layer prepared in step 11, dried at 60°C, and hot-pressed at 100°C and 1.5MPa to obtain a PEM electrolytic cell membrane electrode.

[0063] Figures 2-7 The deformation of the membrane electrodes in the above application examples and comparative examples after frequent start-stop is shown. The electrochemical performance results of the membrane electrodes restored using the methods in the above application examples and comparative examples are shown in Table 1. The frequent start-stop test was performed by running at a current density of 2.0 A / cm² for 60 s, then reducing the current density to 0 and maintaining it for 30 s, repeating this cycle 10,000 times.

[0064] Table 1 shows the electrolytic cell at 2.0 A / cm. 2 Comparison of average cell voltages under current density As shown in Table 1, the electrolytic cell membrane electrodes of Application Examples 1 to 3 of this application exhibit performance degradation within a small range after frequent start-up and shutdown for a period of time, making the electrolytic cell more advantageous in long-term coupling with the fluctuations of renewable energy sources.

[0065] In Comparative Example 1, no composite layer was coated on the anode during the fabrication of the membrane electrode. During initial operation, the reduced thickness resulted in a slight decrease in resistance, thus leading to slightly better performance. Figure 2 As shown, although the membrane electrodes of Comparative Example 1 and each application example showed almost the same degree of deformation after frequent start-up and shutdown, their performance degraded after long-term frequent start-up and shutdown. This is because without the composite layer, hydrogen-oxygen intermingling intensifies, leading to increased deformation of the proton exchange membrane under gas scouring. Furthermore, the absence of proton exchange membrane repair material results in defects such as wrinkles and deformation, thus the average cell voltage is slightly higher compared to the same period last year.

[0066] according to Figure 3 In Comparative Example 2, because no catalyst repair agent was added to the anode catalyst slurry, the anode catalyst material dissolved and detached during frequent start-up and shutdown processes, which led to damage to the integrity of the catalyst layer and thus a significant performance degradation.

[0067] according to Figure 4 In Comparative Example 3, since the anode is not coated with a support layer, the support of the membrane electrode weakens during frequent start-up and shutdown, resulting in wrinkles and thus performance degradation. However, due to the presence of a large amount of deionized water during frequent start-up and shutdown, the anode is kept under positive pressure, thus the effect of anode support is weakened, resulting in a smaller performance degradation.

[0068] according to Figure 5In Comparative Example 4, since no support layer was added to the cathode, this mode caused the most damage to the membrane electrode. During frequent start-up and shutdown, the support of the cathode weakened, which led to the breakage of the cathode gas diffusion layer. The membrane electrode swelled directly and embedded into the cathode flow field channel, resulting in a significant increase in performance degradation.

[0069] according to Figure 6 In Comparative Example 5, since neither the cathode nor the anode has a support layer, the combined effects of Comparative Example 3 and Comparative Example 4 result in the largest performance degradation.

[0070] In Comparative Example 6, because the support layer and catalyst layer were not fabricated as a single unit during the preparation of the membrane electrode, the interlayer bonding force was reduced. Although it still provided support during frequent start-up and shutdown operations, considering that gaps would exist between the independent support layers, these gaps would increase over time. Figure 7 This leads to increased contact resistance, thus causing performance degradation.

[0071] The foregoing has described some specific embodiments of this application. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. A method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode, characterized in that, include: Provide composite slurry one; The composite slurry is coated on one side of a proton exchange membrane and dried to obtain a composite layer. An anode catalyst slurry containing a self-healing catalyst material is provided. The anode catalyst slurry is coated on the surface of the composite layer and dried using a first drying process to obtain the anode catalyst layer. Preparation of composite slurry using a support; The composite slurry is coated onto the surface of the anode catalyst layer and dried using a second drying process. A cathode catalyst slurry is provided, and the cathode catalyst slurry is coated on the other side of a proton exchange membrane and dried to form a gel layer. Provide a support layer; The support layer is attached to the surface of the gel layer, and after drying and hot pressing, a PEM electrolytic cell resistant to frequent start-stop membrane electrode is obtained.

2. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The provided composite slurry includes: Weigh out the free radical scavenger, hydrogen elimination catalyst, and sulfonated graphene oxide separately, and wet them with deionized water; Add binder, proton exchange membrane self-healing material and organic solvent, heat and stir evenly to obtain composite slurry one.

3. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The composite slurry is coated on one side of the proton exchange membrane and dried to obtain a composite layer. The coating speed of the composite slurry is 1-3 m / min, the wet coating thickness is 200-400 μm, and the drying temperature is 70-90℃.

4. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The provision of the anode catalyst slurry containing a catalyst self-healing material includes: Weigh out the anode catalyst and the catalyst self-healing material, add deionized water, and then add the binder to obtain a mixed solution; Disperse the mixed solution; An organic solvent is added, and the mixture is homogeneously dispersed to obtain an anode catalyst slurry. The parameters of the first drying process are: drying temperature 30-50℃, drying time 5-10min.

5. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The preparation of composite slurry II using a support includes: Weigh the support, add the emulsion and binder, then add deionized water and alcohol solvent, and disperse evenly to obtain composite slurry II.

6. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The composite slurry II is coated onto the surface of the anode catalyst layer and dried using a second drying process, wherein: the coating speed of the composite slurry II is 1-3 m / min, and the wet coating thickness is 400-800 μm; the parameters of the second drying process are: drying temperature 70-90℃, and drying time 20-40 min.

7. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The cathode catalyst slurry is provided, wherein: The cathode catalyst slurry comprises a platinum-carbon catalyst, a binder, deionized water, and an alcohol solvent, wherein the mass percentage of platinum in the platinum-carbon catalyst is 40-70%.

8. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The cathode catalyst slurry is coated on the other side of the proton exchange membrane and dried to form a gel layer. The coating speed of the cathode catalyst slurry is 1-3 m / min, the wet coating thickness is 400-600 μm, the drying temperature is 40-60℃, and the drying time is 3-7 min.

9. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The provision of a support layer, wherein the support layer is any one of porous titanium mesh, titanium fiber felt, and porous titanium plate.

10. The method for preparing a PEM electrolytic cell resistant to frequent start-stop membrane electrode according to claim 1, characterized in that, The support layer is attached to the surface of the gel layer, and after drying and hot pressing, a PEM electrolytic cell resistant to frequent start-stop membrane electrode is obtained, wherein: the drying temperature is 60-80℃, the hot pressing temperature is 100-120℃, and the hot pressing pressure is 0.5-1.5MPa.

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