Microporous material component with reinforcing structure, method for producing the same, membrane electrode, and fuel cell

Abstract

The application discloses a microporous material component with reinforced structure, which contains a carbon fiber reinforced layer prepared from a non-woven fabric made of carbon fibers. The gas diffusion layer structure is used to prepare a membrane electrode and a fuel cell stack assembled therefrom, which has reduced gas transmission resistance, can reduce mass transfer polarization, and improve the power density of the system. The application further discloses related preparation methods, membrane electrode assemblies, and fuel cells.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more specifically, to microporous material components used in fuel cells, membrane electrode assemblies containing such microporous material components, and the fabricated fuel cells. Background Technology

[0002] Fuel cells, with their advantages of easy start-up, high energy density, zero emissions, and high energy conversion efficiency, have become an important development direction for power systems now and in the future. Meanwhile, the hydrogen used in fuel cells is widely available; hydrogen produced by electrolyzing water using electricity generated from solar, wind, and tidal power is "green hydrogen," a pollution-free process that is a pathway to energy storage and can also reduce carbon dioxide emissions.

[0003] From the perspective of the structure of fuel cell stack assembly, the hydrogen and air (or oxygen) required for the stack reaction are transported to the surface of the gas diffusion layer substrate through the bipolar plate flow channel, and then transported to the catalyst layer for reaction through concentration diffusion or Knudsen diffusion. At the same time, the liquid water generated or accumulated in the catalyst layer is transferred back to the bipolar plate flow field channel through concentration diffusion or capillary effect.

[0004] However, current fuel cell gas diffusion layers typically consist of a substrate layer and a microporous layer. The microporous layer is mainly composed of conductive agents, such as acetylene black and carbon black, and hydrophobic agents, such as polytetrafluoroethylene (PTFE). For example, Chinese patent application CN 110797540A filed by Sinogene Power Co., Ltd. describes a process where highly conductive materials, carbon nanotubes, hydrophilic agents, and dispersions are mixed to form a homogeneous slurry; the carbon nanotubes used are VGCF-H; and the slurry is uniformly distributed on a support material using screen printing. Alternatively, Chinese patent application CN101662031A filed by General Motors Global Technology Operations Co., Ltd. relates to a gas diffusion layer with a low gas diffusion coefficient, particularly for use in fuel cells. This gas diffusion layer includes a gas-permeable diffusion structure and a microporous layer. The microporous layer comprises multiple anisotropically shaped particles, which reduces the porosity of the microporous layer and increases the tortuosity for transporting gas through it. The microporous layer slurry used in the above patents, during coating, can penetrate into the gas diffusion layer substrate. When the prepared gas diffusion layer is used in fuel cells, the porosity of the slurry-penetrated portion decreases, making it prone to water accumulation and causing mass transfer polarization. Chinese Patent No. CN104769760B, filed by Toyota Motor Corporation, discloses a method for manufacturing a porous layer component, comprising: a step of spray drying a mixture containing carbon and a hydrophobic resin to obtain a powder containing carbon and a hydrophobic resin; a step of generating a paste containing the powder; and a step of extruding or rolling the paste to obtain a sheet-like porous layer component. The porous layer prepared by this method only has a hydrophobic agent and a conductive agent structure, relying on 40% by mass of the hydrophobic agent polytetrafluoroethylene for bonding, resulting in low structural strength and easy breakage. Furthermore, the high hydrophobic agent content leads to reduced conductivity and decreased porosity of the porous layer, which is detrimental to gas transport. Chinese patent application CN114256475A discloses a base layer for a gas diffusion layer in a fuel cell. In this base layer, the number of fibers distributed at an angle α between -45° and the x-axis is 5% or more greater than the number of fibers distributed at an angle α between 45° and 135°. Membrane electrode arrays (MEAs) and fuel cell stacks assembled using this gas diffusion layer structure exhibit reduced mass transfer polarization under the bipolar plate ridges, increasing the effective active area of ​​the MEA and improving the system's power density. However, in actual fuel cell operation, water is generated in the catalyst layer on the cathode side. It must first pass through the microporous layer of the gas diffusion layer, which is in direct contact with the catalyst, to reach the gas diffusion layer base layer. Simultaneously, water on the anode side must also pass through the microporous layer to reach the base layer. This application only emphasizes the orientation of the fiber distribution in the base layer and does not solve the water management problem within the microporous layer. Furthermore, the coating of the microporous layer can lead to intrusion into the base layer, which can severely affect mass transfer performance. Summary of the Invention

[0005] Therefore, one of the objectives of this application is to provide a novel microporous material component that can suppress the disadvantage of reduced porosity caused by the microporous layer slurry penetrating into the substrate layer during the current preparation of gas diffusion layers for fuel cells, which leads to a decrease in the drainage and gas diffusion properties of the gas diffusion layer.

[0006] To address the aforementioned problems, the present invention provides a microporous material component with a reinforced structure.

[0007] In some embodiments, this application provides a microporous material component with a reinforced structure, comprising a carbon fiber reinforcing layer, wherein the carbon fiber reinforcing layer is formed from a nonwoven layer made of carbon fibers and fixed by a continuous network structure formed by melting and cooling a hydrophobic agent to form a structure with nanopores, the hydrophobic agent penetrating into the nonwoven layer by applying a slurry comprising at least the hydrophobic agent to the surface of the nonwoven layer.

[0008] In some embodiments, the first most probable pore size of the nanopores is 125 nm and the second most probable pore size is 15 nm, as determined by mercury intrusion porosimetry.

[0009] In some embodiments, the number of carbon fibers in the carbon fiber reinforcement layer whose distribution direction is within the range of -45° to 45° with respect to the first direction of the microporous material component is 20% or more greater than the number of carbon fibers whose distribution direction is within the range of 45° to 135° with respect to the first direction of the microporous material component.

[0010] In some embodiments, the hydrophobic agent is one or more of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene, and the percentage of the hydrophobic agent in the total weight of the gas diffusion layer microporous layer is 1% to 50%, preferably 20% to 39%.

[0011] In some embodiments, the slurry further includes a conductive agent, which is fixed to the nonwoven fabric layer by a continuous network structure of the hydrophobic agent.

[0012] In some embodiments, the conductive agent comprises, but is not limited to, one or more of carbon black, acetylene black, Ketjen black, SUPER P, carbon nanotubes, graphene, Vulcan XC 72, and Black pearls.

[0013] In some embodiments, the thickness of the microporous material component is 10 μm to 850 μm.

[0014] Other embodiments of this application provide a method for preparing a microporous material component with a reinforced structure as described in any of the above claims, comprising the steps of: preparing an oriented carbon fiber reinforcing layer; preparing a slurry comprising at least a hydrophobic agent; placing the prepared carbon fiber reinforcing layer on a polytetrafluoroethylene backing film, applying the slurry to the surface of the carbon fiber reinforcing layer and the slurry penetrating into the carbon fiber nonwoven fabric layer; drying at a temperature of 50°C to 250°C until the hydrophobic agent at least fixes the carbon fibers; and peeling it off from the backing film and treating it at a temperature of 250°C to 390°C for 10 to 100 minutes to melt the hydrophobic agent and form a continuous network structure.

[0015] In some embodiments, the method further includes adding a conductive agent to the slurry.

[0016] In some embodiments, the method further includes adding a free radical quencher to the slurry.

[0017] In some embodiments, the method employs one or more of the following methods: slot coating, roller coating, direct coating, scraping coating, screen printing, etc., to apply the slurry containing a hydrophobic agent and / or a conductive agent and / or a free radical quencher to the surface of the carbon fiber reinforced layer, and the slurry penetrates into the carbon fiber nonwoven fabric layer.

[0018] In some embodiments, the method for preparing the carbon fiber reinforcement layer includes: rinsing the carbon fiber bundle in a cleaning solvent or graphitizing it; cutting the treated carbon fiber into short carbon fibers and blowing them apart with air to prevent adhesion; settling the obtained short carbon fibers in a web laying machine, applying a transverse airflow to blow the short carbon fibers during the settling process to guide the short carbon fibers into an oriented distribution, obtaining a nonwoven fabric after settling, and uniformly spraying an adhesive.

[0019] In some embodiments, the method for preparing the conductive hydrophobic slurry includes uniformly mixing and stabilizing a conductive agent, a hydrophobic agent, deionized water, an alcohol solvent, a dispersant, a pore-forming agent, a stabilizer, and a free radical quencher in a dispersing apparatus.

[0020] In some embodiments, the short cutting yields short carbon fibers with a length of 3 mm to 100 mm.

[0021] Some embodiments of this application provide a membrane electrode assembly, which includes a cathode-side gas diffusion layer substrate, a cathode-side microporous material component, a cathode-side catalyst layer, a proton exchange membrane, an anode-side catalyst layer, an anode-side microporous material component, and an anode-side gas diffusion layer substrate, which are stacked sequentially; wherein the cathode-side microporous material component or the anode-side microporous material component is a microporous material component with an enhanced structure as described above.

[0022] Some embodiments of this application provide a fuel cell comprising a fuel cell stack consisting of a membrane electrode assembly, electrode plates, current collectors, insulating plates, sealing structures, end plates, etc., as described above.

[0023] The microporous material component with reinforced structure provided in this application can overcome the shortcomings of current gas diffusion layer preparation for fuel cells, where the microporous layer slurry penetrates into the substrate layer, resulting in reduced porosity and consequently reduced drainage and gas diffusion properties of the gas diffusion layer.

[0024] Meanwhile, due to the inclusion of this reinforcing structure, the carbon fiber nonwoven fabric layer can be prepared using a dry method, allowing the carbon fibers to be oriented and guiding water vapor to be transported through the microporous material component in the in-plane or transverse direction, that is, in the direction perpendicular to the front to back of the paper, thereby effectively reducing the occurrence of under-ridge polarization. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a membrane electrode assembly according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the fiber distribution direction within a microporous material component with a reinforced structure according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic flowchart of a method for preparing a microporous material component with an enhanced structure according to an embodiment of the present invention;

[0029] Figure 4 A schematic diagram illustrating the matching relationship between a microporous material component with an enhanced structure based on this application and a bipolar plate;

[0030] Figure 5 The graphs show the test polarization curves of a sample 1 according to an embodiment of this application and a fuel cell prepared according to a conventional gas diffusion layer. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Some embodiments of this application relate to a membrane electrode assembly E including the aforementioned gas diffusion layer, such as... Figure 1 As shown, it includes a cathode-side gas diffusion layer base layer 31a, a cathode-side microporous material component 32a, a cathode-side catalyst layer 21, a proton exchange membrane 1, an anode-side catalyst layer 22, an anode-side microporous material component 32b, and an anode-side gas diffusion layer base layer 31b stacked sequentially. The cathode-side microporous material component 32a and the anode-side microporous material component 32b can both have a structure containing a carbon fiber reinforcement layer. The number of carbon fibers in the carbon fiber reinforcement layer whose distribution direction is within the x-axis (i.e., the direction of the first side L1 of the microporous material component 32) forms an angle a1 of -45° ≤ a1 < 45° is 20% or more greater than the number of fibers within the a2 range of 45° ≤ a2 < 135°. Figure 2 , 4 A schematic diagram of a microporous material component in one embodiment is shown, wherein the included angles a1 and a2 refer to the included angles between the carbon fibers in the plane defined by the first direction (x-axis direction) where the first side L1 of the microporous material components 32a and 32b is located and the second direction (y-axis direction) where the second side L2 is located.

[0033] The microporous material components 32a and 32b having the above-mentioned properties can be prepared by at least the following methods, such as Figure 3As shown: Using T300-48K carbon fiber as raw material, the carbon fiber undergoes high-temperature graphitization treatment at 2500℃ (step S11); the graphitized carbon fiber is cut into short carbon fibers of about 10mm, and air is used as the dispersion medium. A high-speed roller with a rotation speed of 3000 rpm is used to disperse the carbon fiber raw material into single fibers (step S12); the single short carbon fibers obtained in step S12 are then settled in a web-laying machine to obtain a carbon fiber nonwoven fabric. During the settling process, a single transverse airflow is added to guide the carbon fiber to distribute along the airflow direction (step S13); the carbon fiber nonwoven fabric obtained in step S13 is uniformly sprayed with an adhesive to obtain a carbon fiber functional layer (step S14); the carbon fiber functional layer obtained in step S14 is stacked on a polytetrafluoroethylene backing film (step S15); conductive agents, hydrophobic agents, deionized water, alcohol solvents, dispersants, pore-forming agents, stabilizers, free radical quenchers, etc. are added in a dispersion machine. The mixture is thoroughly mixed and stabilized to form a slurry (step S16). One or more methods, such as slot coating, roller coating, direct coating, scraping coating, and screen printing, can be used to coat the slurry prepared in S16 onto the surface of the carbon fiber functional layer obtained in S15, allowing the slurry to penetrate into the carbon fiber nonwoven fabric layer. The slurry is then dried at a temperature of 50℃ to 250℃. This step can be completed in one step or repeated 2 to 3 times (step S17). In this step, deionized water, alcohol solvents, dispersants, pore-forming agents, and stabilizers in the slurry will gradually evaporate or decompose and release. In the final product, the hydrophobic agent polytetrafluoroethylene (PTFE) acts as a binder, fixing the conductive agent, free radical quencher, and carbon fiber. After peeling the carbon fiber functional layer prepared in step S17 from the backing film, it is treated at a temperature of 250℃ to 400℃ for 10 to 100 minutes (step S18). In this step, the dispersant and other components can be completely decomposed, and the hydrophobic agent PTFE melts at this temperature to form a continuous network structure.

[0034] Microporous material components with the above characteristics can be prepared by at least the following method: Using T300-48K carbon fiber as raw material, after high-temperature treatment at 1800℃, it is chopped into short fibers of 8mm length; using air as the dispersion medium, a high-speed roller with a rotation speed of 2800 rpm disperses the carbon fiber raw material into a single fiber state; then, the chopped carbon fiber is carried into a web-laying machine by an airflow fiber conveyor with a flow rate of 280m / s, where the chopped carbon fiber settles by gravity. At least one, preferably multiple, gas ejection holes are distributed on the side wall of the top vertical cylinder, each ejecting gas at a rate of 300mL / min. After settling, a 0.070mm nonwoven base paper is formed; after being output from the conveyor belt of the web-laying machine, the nonwoven fabric is sprayed with an adhesive and dried at 80℃, rolled into rolls, and coated with a 0.5mm thick polytetrafluoroethylene backing film (PTFE backing film) to obtain the nonwoven fabric of the microporous material component; Preparation of the slurry: Take the conductive agent Vulcan... XC-72(R), an aqueous solution containing 2.5g ammonium oxalate, 20% PTFE emulsion, and polyvinylpyrrolidone (PVP) in a mass ratio of 1:22.5:2.5:0.05 were added to a certain amount of isopropanol and homogenized for 2 hours to prepare a slurry. The nonwoven fabric with a backing film was placed on a slot coater, and the prepared slurry was added. The coating was applied at a speed of 0.5m / min, and then dried in a continuous oven at 145℃. The backing film was peeled off during the drying and winding process. The resulting intermediate was dried in an oven at 240℃ for 30 minutes, and then heated in an oven at 350℃ for 60 minutes. After natural cooling, a microporous material component with a thickness of 30µm was obtained. The first most probable pore size was determined to be 125nm and the second most probable pore size was determined to be 15nm by mercury intrusion porosimetry.

[0035] The microporous material components 32a and 32b, prepared using the above method, with a thickness of 30 μm, are mounted with hydrophobically treated gas diffusion layer substrates 31a and 31b (using Toray H060 carbon paper, with a thickness of 190 μm). Figure 1 As shown, the membrane electrode assembly (Sample 1) and the membrane electrode assembly using a gas diffusion layer made from common carbon paper (Toray H060 carbon paper with a coating to increase the micropores, resulting in a gas diffusion layer with a total thickness of 220 μm) were respectively assembled into fuel cells according to the following schemes. The two samples were respectively assembled into active regions with an area of ​​50 cm². 2 The electrochemical performance of the proton exchange membrane fuel cell was tested and compared. Figure 5To prepare test polarization curves for fuel cells using Sample 1 and Sample 2, the data were collected under the following conditions: cathode inlet pressure 20 kPa lower than anode inlet pressure, anode and cathode inlet gas humidity of 40%, temperature of 80°C, and a stoichiometric ratio of 1.8. The results showed that at current densities above 1.0 A / cm², the voltage of the cell prepared using Sample 1 remained stable, while the voltage of the cell prepared using Sample 2 decreased significantly, exhibiting mass transfer polarization. Therefore, the fuel cell prepared using the technical solution of this application demonstrates good performance and superior cell characteristics.

[0036] A top view image of the carbon fiber functional layer obtained in step S14 can be obtained through laser imaging, scanning electron microscopy (SEM), or transmission electron microscopy (TEM). Then, based on the image count, the process is adjusted so that the number of carbon fibers in the carbon fiber functional layer formed in the x-axis direction (i.e., the direction parallel to the first direction of the substrate) with an angle a1 of -45° ≤ a1 < 45° is 20% or more greater than the number of carbon fibers in the 45° ≤ a2 < 135° range. With this percentage increase, after matching with the ridge 801 of the bipolar plate 800, for example, making the parts of the microporous material component E with more fiber distribution, i.e., the parts with an angle of -45° to 45° with the first direction of the microporous material component, set at 90 degrees to the extension direction of the ridge on the bipolar plate, can better guide the gas to achieve in-plane transport or lateral diffusion in the x-direction of the microporous material component, and reduce mass transfer polarization.

[0037] The microporous material component proposed in this application is a single structural component independent of the gas diffusion layer substrate, solving the problem of water permeating through the microporous layer to the substrate layer. A carbon fiber reinforcement layer is added within the microporous material component, and the distribution direction of these carbon fibers can be controlled. Compared to designing the carbon fiber orientation distribution in the substrate layer, this application uses conductive and hydrophobic agents for coating, and achieves good results through low-temperature drying (below 400°C).

[0038] For example, the fabricated microporous material components exhibit a nanoscale pore size distribution, compared to the micrometer-scale pore size distribution of the substrate. The nanoscale pores are close to the pore size of the catalyst layer, which facilitates the formation of continuous pores and generates a capillary effect, a crucial pathway for water drainage from the fuel cell catalyst layer. Compared to traditional substrates, the fabricated microporous material components have a smoother surface and lower roughness, enabling better contact with the catalyst, reducing interfacial contact resistance, and preventing the formation of large interfacial gaps that could lead to water accumulation and mass transfer polarization. The addition of conductive agents can further reduce the bulk resistance of the microporous material components.

[0039] Furthermore, it should be understood that the above-mentioned image detection and carbon fiber counting can be performed at any step after the formation of the nonwoven fabric layer, the formation of the microporous material component, or the formation of the gas diffusion layer, in order to determine whether the formed microporous material component meets the requirements.

[0040] The backing film serves only as a lining during the production process. The slurry penetrates into the carbon fiber nonwoven fabric layer, supported by the backing film. It can be peeled off after drying or during use. Besides polytetrafluoroethylene (PTFE), other materials with similar properties can also be used for the backing film. Due to the influence of drying temperature, it needs to withstand temperatures ranging from 50℃ to 250℃.

[0041] The hydrophobic agent is one or more of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene, and the percentage of the hydrophobic agent in the total weight of the gas diffusion layer microporous layer is 1% to 50%, preferably 20% to 39%.

[0042] The conductive agent includes, but is not limited to, one or more of carbon black, acetylene black, Ketjen black, SUPER P, carbon nanotubes, graphene, Vulcan XC 72, and Black pearls.

[0043] The thickness of the microporous material component can be any value between 10 μm and 850 μm, preferably any value between 20 μm and 50 μm.

[0044] In addition to 10mm, carbon fibers can also be cut into any length between 3mm and 100mm.

[0045] The carbon fiber nonwoven fabric obtained by settling inside the web laying machine is not limited to using short fibers of one length; carbon fiber nonwoven fabrics can be formed using short fibers of different lengths.

[0046] This application can be implemented using the following specific examples:

[0047] 1. A microporous material component with a reinforced structure, characterized in that: the microporous material component includes a carbon fiber reinforcing layer, wherein the carbon fiber reinforcing layer is formed by a nonwoven fabric layer made of carbon fibers and fixed by a continuous network structure formed by melting and cooling a hydrophobic agent to form a structure with nanopores, wherein the hydrophobic agent penetrates into the nonwoven fabric layer by applying a slurry comprising at least the hydrophobic agent to the surface of the nonwoven fabric layer.

[0048] 2. The microporous material component with an enhanced structure according to Example 1, characterized in that: the first most probable pore size of the nanopores, as determined by mercury intrusion porosimetry, is 125 nm, and the second most probable pore size is 15 nm.

[0049] 3. The microporous material component with reinforced structure according to Example 1, characterized in that: the number of carbon fibers in the carbon fiber reinforcement layer whose distribution direction is within the range of -45° to 45° with respect to the first direction of the microporous material component is 20% or more greater than the number of carbon fibers whose distribution direction is within the range of 45° to 135° with respect to the first direction of the microporous material component.

[0050] 4. The microporous material component with reinforced structure according to Example 1, characterized in that: the hydrophobic agent is one or more of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene, and the percentage of the hydrophobic agent in the total weight of the gas diffusion layer microporous layer is 1% to 50%, preferably 20% to 39%.

[0051] 5. The microporous material component with an enhanced structure according to Example 1, characterized in that: the slurry further includes a conductive agent, which is fixed to the nonwoven fabric layer by a continuous network structure of the hydrophobic agent.

[0052] 6. The microporous material component with an enhanced structure according to Example 5, characterized in that: the conductive agent comprises, but is not limited to, one or more of carbon black, acetylene black, Ketjen black, SUPER P, carbon nanotubes, graphene, Vulcan XC 72, and black pearls.

[0053] 7. The microporous material component with an enhanced structure according to Example 1, characterized in that: the thickness of the microporous material component is 10 μm to 850 μm.

[0054] 8. A method for preparing a microporous material component with a reinforced structure as described in any one of Examples 1 to 6, characterized in that it comprises the steps of: preparing an oriented carbon fiber reinforcing layer; preparing a slurry comprising at least a hydrophobic agent; placing the prepared carbon fiber reinforcing layer on a polytetrafluoroethylene backing film, applying the slurry to the surface of the carbon fiber reinforcing layer and the slurry penetrating into the carbon fiber nonwoven fabric layer; drying at a temperature of 50°C to 250°C until the hydrophobic agent at least fixes the carbon fibers; and peeling it off from the backing film and treating it at a temperature of 250°C to 390°C for 10 to 100 minutes to melt the hydrophobic agent and form a continuous network structure.

[0055] 9. The method for preparing a microporous material component with an enhanced structure according to Example 7 is characterized in that: it further includes adding a conductive agent to the slurry.

[0056] 10. The method for preparing a microporous material component with an enhanced structure according to Example 7, characterized in that: it further includes adding a free radical quencher to the slurry.

[0057] 11. A method for preparing a microporous material component with a reinforced structure according to any one of Examples 7 to 9, characterized in that: the slurry containing a hydrophobic agent and / or a conductive agent and / or a free radical quencher is applied to the surface of the carbon fiber reinforced layer by one or more of the following methods: slot coating, roller coating, direct coating, scraping coating, screen printing, etc., and the slurry penetrates into the carbon fiber nonwoven fabric layer.

[0058] 12. The method for preparing a microporous material component with a reinforced structure according to Example 7 is characterized in that: the preparation of the carbon fiber reinforcing layer includes: rinsing the carbon fiber bundle in a cleaning solvent or performing graphitization treatment; cutting the treated carbon fiber into short carbon fibers and blowing them apart with air to prevent adhesion; settling the obtained short carbon fibers in a web laying machine, applying a transverse airflow to blow the short carbon fibers during the settling process to guide the short carbon fibers to be oriented; obtaining a nonwoven fabric after settling and uniformly spraying an adhesive.

[0059] 13. The method for preparing a microporous material component with an enhanced structure according to Example 7 is characterized in that: the preparation of the conductive hydrophobic slurry includes uniformly mixing and stabilizing a conductive agent, a hydrophobic agent, deionized water, an alcohol solvent, a dispersant, a pore-forming agent, a stabilizer, and a free radical quencher in a dispersing apparatus.

[0060] 14. The method for preparing a microporous material component with an enhanced structure according to Example 7, characterized in that: the short cutting yields short carbon fibers with a length of 3 mm to 100 mm.

[0061] 15. A membrane electrode assembly, characterized in that the membrane electrode assembly comprises: a cathode-side gas diffusion layer substrate, a cathode-side microporous material component, a cathode-side catalyst layer, a proton exchange membrane, an anode-side catalyst layer, an anode-side microporous material component, and an anode-side gas diffusion layer substrate, which are sequentially stacked; wherein the cathode-side microporous material component or the anode-side microporous material component is a microporous material component with an enhanced structure as described in Examples 1 to 7;

[0062] 16. A fuel cell, characterized in that the fuel cell comprises a fuel cell stack consisting of a membrane electrode assembly, electrode plates, current collectors, insulating plates, sealing structures, end plates, etc., as described in Example 15.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microporous material component with a reinforced structure, characterized in that: The microporous material component is a single structural component independent of the gas diffusion layer substrate; the microporous material component includes a carbon fiber reinforcement layer, wherein the carbon fiber reinforcement layer is formed by a nonwoven fabric layer made of carbon fibers and fixed by a continuous network structure formed by melting and cooling a hydrophobic agent to form a structure with nanopores, and the hydrophobic agent penetrates into the nonwoven fabric layer by applying a slurry containing at least the hydrophobic agent to the surface of the nonwoven fabric layer. The first most probable pore size of the nanopores was determined to be 125 nm and the second most probable pore size to be 15 nm according to the mercury porosimetry method. The number of carbon fibers in the carbon fiber reinforcement layer whose distribution direction is within the range of -45° to 45° with respect to the first direction of the microporous material component is 20% or more greater than the number of carbon fibers whose distribution direction is within the range of 45° to 135° with respect to the first direction of the microporous material component.

2. The microporous material component with reinforced structure according to claim 1, characterized in that: The hydrophobic agent is one or more of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated ethylene propylene, and the percentage of the hydrophobic agent in the total weight of the gas diffusion layer microporous layer is 1% to 50%.

3. The microporous material component with reinforced structure according to claim 2, characterized in that: The hydrophobic agent accounts for 20% to 39% of the total weight of the gas diffusion layer microporous layer.

4. The microporous material component with reinforced structure according to claim 1, characterized in that: The slurry also includes a conductive agent, which is fixed to the nonwoven fabric layer by the continuous network structure of the hydrophobic agent.

5. The microporous material component with a reinforced structure according to claim 1, characterized in that: The conductive agent is one or more of carbon black, carbon nanotubes, and graphene.

6. The microporous material component with a reinforced structure according to claim 1, characterized in that: The thickness of the microporous material component is 10 μm to 850 μm.

7. A method for preparing a microporous material component with an enhanced structure as described in any one of claims 1 to 6, characterized in that, The method includes the following steps: preparing an oriented carbon fiber reinforcing layer; preparing a slurry containing at least a hydrophobic agent; placing the prepared carbon fiber reinforcing layer on a polytetrafluoroethylene backing film, applying the slurry to the surface of the carbon fiber reinforcing layer and allowing the slurry to penetrate into the carbon fiber nonwoven fabric layer; drying at a temperature of 50°C to 250°C until the hydrophobic agent at least fixes the carbon fibers; and peeling it off from the backing film and treating it at a temperature of 250°C to 390°C for 10 to 100 minutes to melt the hydrophobic agent and form a continuous network structure.

8. A membrane electrode assembly, characterized in that, The membrane electrode assembly includes: a cathode-side gas diffusion layer substrate, a cathode-side microporous material component, a cathode-side catalyst layer, a proton exchange membrane, an anode-side catalyst layer, an anode-side microporous material component, and an anode-side gas diffusion layer substrate, which are stacked sequentially; wherein the cathode-side microporous material component or the anode-side microporous material component is a microporous material component with an enhanced structure as described in any one of claims 1 to 6.

9. A fuel cell, characterized in that, The fuel cell is a fuel cell stack comprising the membrane electrode assembly, electrode plate, current collector, insulating plate, sealing structure and end plate as described in claim 8.

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