An anti-reverse gas diffusion layer, a preparation method thereof, a membrane electrode and a fuel cell

Abstract

The application discloses an anti-reverse polarity gas diffusion layer and a preparation method thereof, a membrane electrode and a fuel cell. A first slurry is prepared by using a first solvent, a first surfactant, a first conductive carbon material and a first hydrophobic resin; a second slurry is prepared by using a second solvent, a second surfactant, a gamma-MnO2 water electrolysis catalyst, a third solvent, a third surfactant, a second conductive carbon material, PMMA nano powder and PTFE emulsion; the first slurry is coated on a carbon base material, dried, the second slurry is coated, dried and heat-treated to obtain the anti-reverse polarity gas diffusion layer. The method of the application adopts the non-noble metal water electrolysis catalyst gamma-MnO2; the distribution uniformity is good, and the system is stable; the water electrolysis catalyst is not added in the first microporous layer, and the water electrolysis catalyst is added in the second microporous layer, so that the utilization rate of the water electrolysis catalyst is high, and the cost is low; the anti-reverse polarity performance of the gas diffusion layer is good, the process is easy to realize, and the gas diffusion layer can be mass-produced.

Description

Technical Field

[0001] This invention relates to the field of fuel cells, and more specifically, to an anti-reverse gas diffusion layer and its preparation method, a membrane electrode assembly, and a fuel cell. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) have attracted widespread attention due to their advantages of low operating temperature, low noise, and no pollution. The membrane electrode assembly (MEA), typically composed of a proton exchange membrane, a catalyst layer, and a gas diffusion layer (GDL), is a key component of hydrogen proton exchange membrane fuel cells.

[0003] During actual operation, fuel cell stacks may experience situations where one or more cells have negative voltages, meaning the anode potential of one or more cells is higher than the cathode potential—a phenomenon known as "reverse polarity." Reverse polarity causes significant and irreversible damage to the battery's performance, severely impacting its capabilities and durability. Insufficient hydrogen in the anode catalyst layer can lead to reverse polarity. Factors such as insufficient external hydrogen supply, impurities clogging gas transport channels, and flooding can cause hydrogen shortages in the anode catalyst layer. Under dynamic operating conditions, such as start-up, shutdown, and rapid load changes, hydrogen supply may be delayed, making the anode catalyst layer prone to short-term hydrogen shortages. All these factors can induce reverse polarity.

[0004] Currently, membrane electrode assemblies (MEAs) with anti-reverse polarization capabilities typically incorporate catalyst powders such as IrO2 and RuO2, which have water electrolysis capabilities, into the anode catalyst layer to enhance anti-reverse polarization performance. However, if the added substances are detrimental to the electrochemical reaction between hydrogen and oxygen, it can negatively impact the performance of the catalyst layer. Research on gas diffusion layers with anti-reverse polarization capabilities is limited. Therefore, research on gas diffusion layers with excellent anti-reverse polarization performance is of great significance. Summary of the Invention

[0005] This invention is based on the inventors' discoveries and understanding of the following facts and problems: The gas diffusion layer comprises a substrate layer and a microporous layer (MPL). In hydrogen gas exchange membrane fuel cells, the gas diffusion layer mainly functions as a catalyst support, electrode structure support, water drainage and gas transfer, and electrical conductivity. The gas diffusion layer determines the performance and lifespan of the fuel cell. Currently, membrane electrodes with anti-reverse polarity typically incorporate water electrolysis catalyst powder into the anode catalyst layer to enhance anti-reverse polarity. Research on gas diffusion layers with anti-reverse polarity is relatively limited and has several drawbacks: adding water electrolysis catalysts to both the substrate layer and the microporous layer results in low catalyst utilization and high cost; uneven catalyst dispersion leads to poor anti-reverse polarity performance and inconsistent product quality; and the preparation process is cumbersome and requires sophisticated equipment. Therefore, there is an urgent need to provide a gas diffusion layer with high utilization of water electrolysis catalysts, uniform distribution, low cost, simple preparation process, and excellent anti-reverse polarity performance.

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a method for preparing an anti-reverse polarity gas diffusion layer. Using a non-precious metal water electrolysis catalyst γ-MnO2, the uniformity of the water electrolysis catalyst distribution and system stability are improved through the microporous layer slurry composition, slurry preparation process, and dispersion process. A double-layer microporous layer is employed, with no water electrolysis catalyst added to the first microporous layer and the second microporous layer containing the catalyst, thereby improving the utilization rate of the water electrolysis catalyst and reducing costs. The gas diffusion layer exhibits good anti-reverse polarity performance, and the process is easy to implement and can be mass-produced.

[0007] A method for preparing an anti-reverse polarity gas diffusion layer according to an embodiment of the present invention includes the following steps:

[0008] (1) Mix the first solvent, the first surfactant and the first conductive carbon material evenly, and then add the first hydrophobic resin and mix evenly to obtain the first slurry;

[0009] (2) The second solvent, the second surfactant and the γ-MnO2 water electrolysis catalyst are mixed evenly to obtain the first mixed slurry;

[0010] The third solvent, the third surfactant, the second conductive carbon material, and PMMA nanopowder are mixed evenly to prepare the second mixed slurry;

[0011] The second mixed slurry is added to the first mixed slurry and mixed evenly to obtain the third mixed slurry; PTFE emulsion is added to the third mixed slurry and mixed evenly to obtain the second slurry;

[0012] (3) The first slurry is coated on a carbon substrate and dried to form a first coating layer; the second slurry is coated on the first coating layer and dried to obtain a second coating layer; then heat treatment is performed so that the first coating layer forms a first microporous layer and the second coating layer forms a second microporous layer, thereby obtaining the anti-reverse gas diffusion layer.

[0013] The advantages and technical effects of the method for preparing the anti-reverse polarity gas diffusion layer according to the embodiments of the present invention are as follows: 1. In the embodiments of the present invention, a non-precious metal water electrolysis catalyst γ-MnO2 is used. γ-MnO2 has high water electrolysis efficiency. When the fuel cell experiences reverse polarity, it promotes the decomposition of water, releases electrons and protons, maintains charge balance, protects the carbon support in the catalyst layer, and avoids catalyst layer collapse and proton membrane perforation. Compared with precious metal oxide catalysts, it has low cost and good anti-reverse polarity effect. The traditional method directly adds water electrolysis catalysts such as IrO2 or RuO2 to the gas diffusion layer. The utilization rate of the water electrolysis catalyst is low and it is easy to settle. In the present invention, by adopting a double microporous layer and optimizing the composition of the microporous layer slurry, slurry preparation process and dispersion process, the uniformity of the distribution of the water electrolysis catalyst in the microporous layer slurry is improved. The system is stable, not easy to settle, the utilization rate of the water electrolysis catalyst is high, and the anti-reverse polarity effect is good. At the same time, it will not have a negative impact on the battery performance of the gas diffusion layer.

[0014] 2. In this embodiment of the invention, a double-layer microporous layer is used. No water electrolysis catalyst is added to the first microporous layer, while a non-precious metal water electrolysis catalyst γ-MnO2 is added to the second microporous layer. This improves the utilization rate of the water electrolysis catalyst, reduces the amount of catalyst used, lowers costs, and enhances the anti-reverse polarity function. In the first coating layer, the first conductive carbon material and the first hydrophobic resin have good encapsulation properties and strong hydrophobicity, playing an important role in the water vapor management of the gas diffusion layer. In the second coating layer, the second surfactant improves the uniformity of the distribution of the γ-MnO2 water electrolysis catalyst in the microporous layer slurry, making the system stable and less prone to sedimentation. PMMA (polymethyl methacrylate) nanopowder and the third surfactant jointly promote the dispersion of the second conductive carbon material in the second coating layer. The resulting anti-reverse polarity gas diffusion layer has a smooth, crack-free surface. Furthermore, after heat treatment, PMMA decomposes, generating a rich pore structure, improving the apparent smoothness of the microporous layer, enhancing the electrical properties of the anti-reverse polarity gas diffusion layer, and improving the anti-reverse polarity capability.

[0015] 3. In the embodiments of the present invention, the gas diffusion layer obtained has good anti-reverse polarity performance, the process is easy to implement, and it can be mass-produced.

[0016] In some embodiments, in step (3), the loading of γ-MnO2 in the second coating layer is 7.5-35 μg / cm³. 2 .

[0017] In some embodiments, in step (3), the loading of γ-MnO2 in the second coating layer is 15-30 μg / cm³. 2 .

[0018] In some embodiments, in step (3), the thickness of the first coating layer is 20-35 μm; the thickness of the second coating layer is 5-20 μm.

[0019] In some embodiments, in step (1), the first solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the first surfactant includes at least one of Triton-X100, Tween 60, and fatty alcohol polyoxyethylene ether; the first conductive carbon material includes at least one of XC-72R, BP2000, acetylene black, Ketjen black, graphite powder, and expanded graphite; the first hydrophobic resin includes at least one of PTFE emulsion, fluorinated ethylene propylene copolymer, and polyvinylidene fluoride; and the mass ratio of the first surfactant, the first conductive carbon material, and the first hydrophobic resin is 0.1-1:0.1-10:0.1-2.

[0020] In some embodiments, in step (2), the second solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the second surfactant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and sodium lauroyl-N-methylaminoacetate; the third solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the second conductive carbon material includes carbon nanofibers, and also includes acetylene black, XC-72R, and BP2. The second conductive carbon material contains at least one of 000, graphite powder, and Ketjen black; the third surfactant includes at least one of Triton-X100, Tween 60, FC4430, or AEO-9; the carbon nanofibers in the second conductive carbon material are not less than 2 wt%; the mass ratio of the second surfactant, γ-MnO2 water electrolysis catalyst, third surfactant, second conductive carbon material, PMMA nanopowder, and PTFE emulsion is 0.1-1:0.5-5:0.1-1:0.7-14:0.1-2:0.1-2.

[0021] In some embodiments, in step (3), the heat treatment includes a first heat treatment and a second heat treatment. The temperature of the first heat treatment is 200-250°C and the time of the first heat treatment is 5-15 min. The temperature of the second heat treatment is 350-400°C and the time of the second heat treatment is 10-30 min.

[0022] An anti-reverse polarity gas diffusion layer according to an embodiment of the present invention is prepared using the preparation method of the present invention. In this embodiment, the anti-reverse polarity gas diffusion layer uses a non-precious metal water electrolysis catalyst γ-MnO2; it exhibits good uniformity in distribution and system stability; it employs a double-layer microporous layer, with no water electrolysis catalyst added to the first microporous layer and the water electrolysis catalyst added to the second microporous layer, thereby improving the utilization rate of the water electrolysis catalyst and reducing costs; the gas diffusion layer demonstrates good anti-reverse polarity performance, and the process is easy to implement, enabling mass production.

[0023] An embodiment of the present invention provides a membrane electrode that uses the anti-reverse polarity gas diffusion layer of the present invention as the anode gas diffusion layer. In this embodiment, the membrane electrode using the anti-reverse polarity gas diffusion layer of the present invention as the anode gas diffusion layer exhibits good anti-reverse polarity performance and low cost.

[0024] A fuel cell according to an embodiment of the present invention includes a membrane electrode assembly (MEA). In this embodiment, the fuel cell exhibits good anti-reverse polarity performance and is suitable for mass production. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the anti-reverse polarity gas diffusion layer prepared according to the present invention.

[0026] Figure 2 This is a SEM image of the anti-reverse polarity gas diffusion layer of Embodiment 1 of the present invention.

[0027] Figure 3 This is a comparison chart of the performance of a single cell before and after reversal in Embodiment 1 of the present invention.

[0028] Figure 4 This is a comparison chart of the performance of a single cell before and after the reverse electrode in Comparative Example 1 of this invention. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] A method for preparing an anti-reverse polarity gas diffusion layer according to an embodiment of the present invention includes the following steps:

[0031] (1) Mix the first solvent, the first surfactant and the first conductive carbon material evenly, and then add the first hydrophobic resin and mix evenly to obtain the first slurry;

[0032] (2) The second solvent, the second surfactant and the γ-MnO2 water electrolysis catalyst are mixed evenly to obtain the first mixed slurry;

[0033] The third solvent, the third surfactant, the second conductive carbon material, and PMMA nanopowder are mixed evenly to prepare the second mixed slurry;

[0034] The second mixed slurry is added to the first mixed slurry and mixed evenly to obtain the third mixed slurry; PTFE emulsion is added to the third mixed slurry and mixed evenly to obtain the second slurry;

[0035] (3) The first slurry is coated on a carbon substrate and dried to form a first coating layer; the second slurry is coated on the first coating layer and dried to obtain a second coating layer; then heat treatment is performed so that the first coating layer forms a first microporous layer and the second coating layer forms a second microporous layer, thereby obtaining the anti-reverse gas diffusion layer.

[0036] The method for preparing the anti-reverse polarity gas diffusion layer in this invention uses a non-precious metal water electrolysis catalyst, γ-MnO2. γ-MnO2 has high water electrolysis efficiency and promotes water decomposition, releasing electrons and protons, maintaining charge balance, protecting the carbon support in the catalyst layer, and preventing catalyst layer collapse and proton membrane perforation when reverse polarity occurs in the fuel cell. Compared with precious metal oxide catalysts, it is lower in cost and has better anti-reverse polarity performance. Traditional methods directly add water electrolysis catalysts such as IrO2 or RuO2 to the gas diffusion layer, resulting in low utilization of the water electrolysis catalyst and easy sedimentation. In this invention, by using a double-layer microporous layer and optimizing the composition of the microporous layer slurry, slurry preparation process, and dispersion process, the uniformity of the distribution of the water electrolysis catalyst in the microporous layer slurry is improved, the system is stable, not easy to settle, the utilization rate of the water electrolysis catalyst is high, and the anti-reverse polarity effect is good, while not negatively affecting the battery performance of the gas diffusion layer. In this embodiment of the invention, a double-layer microporous layer is employed. No water electrolysis catalyst is added to the first microporous layer, while a non-precious metal water electrolysis catalyst γ-MnO2 is added to the second microporous layer. This improves the utilization rate of the water electrolysis catalyst, reduces its dosage, lowers costs, and enhances the anti-reverse polarity function. In the first coating layer, the first conductive carbon material and the first hydrophobic resin exhibit good encapsulation properties and strong hydrophobicity, playing a crucial role in water vapor management of the gas diffusion layer. In the second coating layer, the second surfactant enhances the uniformity of the γ-MnO2 water electrolysis catalyst distribution in the microporous layer slurry, resulting in a stable system that is less prone to sedimentation. PMMA (polymethyl methacrylate) nanopowder and the third surfactant jointly promote the dispersion of the second conductive carbon material in the second coating layer. The resulting anti-reverse polarity gas diffusion layer has a smooth, crack-free surface. Furthermore, after heat treatment, PMMA decomposes, generating a rich pore structure, improving the apparent smoothness of the microporous layer, enhancing the electrical properties of the anti-reverse polarity gas diffusion layer, and improving its anti-reverse polarity capability. In this embodiment of the invention, the gas diffusion layer has good anti-reverse polarity performance, is easy to process, and can be mass-produced.

[0037] In some embodiments, in step (3), the loading of γ-MnO2 in the second coating layer is 7.5-35 μg / cm³. 2 Preferably, the loading of γ-MnO2 is 15-30 μg / cm³. 2 In this embodiment of the invention, during membrane electrode reversal, the γ-MnO2 water electrolysis catalyst can accelerate water decomposition, provide the necessary electrons, maintain balance, thereby reducing carbon corrosion in the catalyst layer and extending its service life. Excessive γ-MnO2 loading leads to decreased conductivity of the gas diffusion layer; insufficient γ-MnO2 loading results in poor anti-reversal performance.

[0038] In some embodiments, in step (3), the thickness of the first coating layer is 20-35 μm, preferably 20-30 μm; the thickness of the second coating layer is 5-20 μm, preferably 10-20 μm. In this embodiment of the invention, by optimizing the thickness of the first and second coating layers, the first microporous layer and the second microporous layer containing the γ-MnO2 water electrolysis catalyst work together to further improve the anti-reverse polarity performance of the gas diffusion layer and the performance of the fuel cell.

[0039] In some embodiments, in step (1), the first solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the first surfactant includes at least one of Triton-X100, Tween 60, and fatty alcohol polyoxyethylene ether; the first conductive carbon material includes at least one of XC-72R, BP2000, acetylene black, Ketjen black, graphite powder, and expanded graphite; the first hydrophobic resin includes at least one of PTFE emulsion, fluorinated ethylene propylene copolymer (FEP), and polyvinylidene fluoride (PVDF); the mass ratio of the first surfactant, the first conductive carbon material, and the first hydrophobic resin is 0.1-1:0.1-10:0.1-2, preferably 1:1.8:1. In some embodiments, the solid content of the PTFE emulsion is 60 wt%. In this embodiment of the invention, the first surfactant can fully mix and coat the first conductive carbon material and the first hydrophobic resin; different types of conductive carbon materials can form different pore size distributions, and the addition of the first conductive carbon material can form a microporous layer with the first pore size distribution, which is beneficial to improving the water vapor management capability of the gas diffusion layer; by optimizing the mass ratio of the first surfactant, the first conductive carbon material and the first hydrophobic resin, the anti-reverse polarity performance, water vapor management performance and battery performance of the anti-reverse polarity gas diffusion layer can be further improved.

[0040] In some embodiments, in step (2), the second solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the second surfactant includes at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and sodium lauroyl-N-methylaminoacetate; the third solvent includes at least one of water, isopropanol, n-propanol, ethanol, and n-butanol; the second conductive carbon material includes carbon nanofibers, and also includes at least one of acetylene black, XC-72R, BP2000, graphite powder, and Ketjen black; the third surfactant includes at least one of Triton-X100, Tween 60, FC4430, or AEO-9. In this embodiment of the invention, the second conductive carbon material including carbon nanofibers can suppress the generation of cracks. The second surfactant can improve the uniformity of the distribution of γ-MnO2 water electrolysis catalyst in the slurry, making the system stable and less prone to sedimentation, which is beneficial to improving the water vapor management performance of the anti-reverse gas diffusion layer and the battery performance. The second conductive carbon material can form a microporous layer with a second pore size distribution, and the PMMA decomposes after heat treatment, producing a rich pore structure. The third surfactant and PMMA nanopowder can fully mix and disperse the carbon nanofibers in the solvent and PTFE (polytetrafluoroethylene) emulsion, promoting the dispersion of carbon nanofibers in the second coating layer.

[0041] In some embodiments, the carbon nanofibers in the second conductive carbon material are not less than 2 wt%, optionally not less than 25 wt%, and preferably not less than 40 wt%. In some embodiments, the carbon nanofibers are synthetic carbon nanofibers, preferably with a fiber diameter of 50-200 nm and a fiber length of 1-10 μm. In this embodiment of the invention, the content and type of carbon nanofibers in the second conductive carbon material are optimized, thereby further improving the anti-reverse polarity performance of the anti-reverse polarity gas diffusion layer and the battery performance.

[0042] In some embodiments, in step (2), the solid content of the PTFE emulsion is 60 wt%.

[0043] In some embodiments, in step (2), the mass ratio of the second surfactant, γ-MnO2 water electrolysis catalyst, third surfactant, second conductive carbon material, PMMA nanopowder, and PTFE emulsion is 0.1-1:0.5-5:0.1-1:0.7-14:0.1-2:0.1-2. In this embodiment of the invention, the mass ratio of each raw material is optimized, thereby further improving the anti-reverse polarity performance of the anti-reverse gas diffusion layer, the water vapor management performance, and the battery performance.

[0044] In some embodiments, in step (2), the second mixed slurry is added to the first mixed slurry in batches; and PTFE emulsion is added to the third mixed slurry in batches.

[0045] In some embodiments, step (3) includes a first heat treatment and a second heat treatment. The temperature of the first heat treatment is 200-250°C, and the time is 5-15 minutes. The temperature of the second heat treatment is 350-400°C, and the time is 10-30 minutes. In this embodiment of the invention, a single drastic temperature rise can cause cracks in the gas diffusion layer. Performing two heat treatments helps to reduce the cracks in the gas diffusion layer caused by drastic temperature rise.

[0046] In some embodiments, the mixing method in step (1) is ball milling. In this embodiment of the invention, ball milling in step (1) facilitates the thorough mixing and coating of the first conductive carbon material and the first hydrophobic resin, thereby further improving the hydrophilicity and hydrophobicity of the obtained first microporous layer and providing excellent water vapor management capabilities.

[0047] In some embodiments, the mixing method in step (2) is ball milling. In this embodiment of the invention, ball milling in step (2) facilitates the thorough mixing and coating of the γ-MnO2 water electrolysis catalyst, the second conductive carbon material, PMMA nanopowder, and PTFE emulsion, thereby further improving the uniformity of the distribution of the water electrolysis catalyst. The PMMA decomposes at high temperature to produce a rich and uniform distribution of pore structures, improving the hydrophilicity and hydrophobicity of the obtained second microporous layer, and providing excellent water vapor management capabilities.

[0048] In some embodiments, in step (3), the carbon substrate is a hydrophobic carbon paper substrate.

[0049] In some embodiments, in step (3), the coating is performed using slot extrusion coating.

[0050] In some embodiments, in step (3), the drying temperature of the first slurry to form the first coating layer is 60-150°C, preferably 80°C, and the drying time is 5-15 min; the drying temperature of the second slurry to form the second coating layer is 60-150°C, preferably 80°C, and the drying time is 5-15 min.

[0051] An anti-reverse polarity gas diffusion layer according to an embodiment of the present invention is prepared using the preparation method of the present invention. In this embodiment, the anti-reverse polarity gas diffusion layer uses a non-precious metal water electrolysis catalyst γ-MnO2; it exhibits good uniformity in distribution and system stability; it employs a double-layer microporous layer, with no water electrolysis catalyst added to the first microporous layer and the water electrolysis catalyst added to the second microporous layer, thereby improving the utilization rate of the water electrolysis catalyst and reducing costs; the gas diffusion layer demonstrates good anti-reverse polarity performance, and the process is easy to implement and can be mass-produced.

[0052] An embodiment of the present invention provides a membrane electrode that uses the anti-reverse polarity gas diffusion layer of the present invention as the anode gas diffusion layer. In this embodiment, the membrane electrode using the anti-reverse polarity gas diffusion layer of the present invention as the anode gas diffusion layer exhibits good anti-reverse polarity performance and low cost.

[0053] A fuel cell according to an embodiment of the present invention includes a membrane electrode assembly (MEA). In this embodiment, the fuel cell exhibits good anti-reverse polarity performance and is suitable for mass production.

[0054] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0055] Example 1

[0056] 1.1 MPL slurry preparation:

[0057] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 10 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0058] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0059] Then, 15 parts by weight of acetylene black, 5 parts by weight of carbon nanofiber, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0060] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 11.5 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min respectively to obtain the second slurry.

[0061] 1.2 Coating of MPL slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form a first coating layer with a thickness of 30 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 min to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 15 μg / cm³. 2 ;

[0062] 1.3 GDL Heat Treatment: The coated layer was subjected to two high-temperature heat treatments. The first heat treatment was performed at 250°C for 10 minutes, and the second heat treatment was performed at 380°C for 30 minutes. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0063] 1.4 MEA preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the CCM (SPICHE-150kW-CCM) was matched. The membrane electrode was fabricated using a mature membrane electrode preparation process.

[0064] 1.5 Single Cell Assembly and Testing: The above membrane electrode assembly was used to assemble a single cell, and the cell performance was tested using a fuel cell testing system. The test conditions were as follows: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0065] Example 2

[0066] 2.1 MPL slurry preparation:

[0067] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 10 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0068] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0069] Then, 15 parts by weight of acetylene black, 5 parts by weight of carbon nanofiber, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0070] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 11.5 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min respectively to obtain the second slurry.

[0071] 2.2 Coating of MPL Slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 minutes to form a first coating layer with a thickness of 20 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 minutes to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 30 μg / cm³. 2 ;

[0072] 2.3 GDL Heat Treatment: The coated layer was subjected to two high-temperature heat treatments. The first heat treatment was performed at 250°C for 10 minutes, and the second heat treatment was performed at 380°C for 30 minutes. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0073] 2.4 MEA preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the matching CCM (SPICHE-150kW-CCM) was used to prepare the membrane electrode using a mature membrane electrode preparation process.

[0074] 2.5 Single Cell Assembly and Testing: The above membrane electrode assembly was used to assemble a single cell, and the cell performance was tested using a fuel cell testing system. The test conditions were as follows: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0075] Example 3

[0076] 3.1 MPL slurry preparation:

[0077] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 10 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0078] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0079] Then, 15 parts by weight of acetylene black, 5 parts by weight of carbon nanofiber, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0080] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 11.5 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min respectively to obtain the second slurry.

[0081] 3.2 Coating of MPL slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form a first coating layer with a thickness of 35 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 min to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 7.5 μg / cm³. 2 ;

[0082] 3.3 GDL Heat Treatment: The coated layer was subjected to two high-temperature heat treatments. The first heat treatment was performed at 250°C for 10 minutes, and the second heat treatment was performed at 380°C for 30 minutes. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0083] 3.4 MEA preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the matching CCM (SPICHE-150kW-CCM) was used to prepare the membrane electrode using a mature membrane electrode preparation process.

[0084] 3.5 Single Cell Assembly and Testing: The above membrane electrode assembly was used to assemble a single cell, and the cell performance was tested using a fuel cell testing system. The test conditions were as follows: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0085] Example 4

[0086] 4.1 MPL slurry preparation:

[0087] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 10 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0088] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0089] Then, 15 parts by weight of acetylene black, 5 parts by weight of carbon nanofiber, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0090] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 10 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min respectively to obtain the second slurry.

[0091] 4.2 Coating of MPL slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form a first coating layer with a thickness of 30 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 min to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 15 μg / cm³. 2 ;

[0092] 4.3 GDL Heat Treatment: The coated layer is subjected to two high-temperature heat treatments. The first heat treatment temperature is 250℃ and the heat treatment time is 10 min; the second heat treatment temperature is 380℃ and the heat treatment time is 30 min. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0093] 4.4 MEA Preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the matching CCM (SPICHE-150kW-CCM) was used to prepare the membrane electrode using a mature membrane electrode preparation process.

[0094] 4.5 Single Cell Assembly and Testing: The above membrane electrode assembly was used to assemble a single cell, and the cell performance was tested using a fuel cell testing system. The test conditions were as follows: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0095] Example 5

[0096] 5.1 MPL slurry preparation:

[0097] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 10 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0098] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0099] Then, 15 parts by weight of Cabot XC-72R, 5 parts by weight of carbon nanofibers, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0100] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 10 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min each time to obtain the second slurry.

[0101] 5.2 Coating of MPL slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form a first coating layer with a thickness of 30 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 min to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 15 μg / cm³. 2 ;

[0102] 5.3 GDL Heat Treatment: The coated layer was subjected to two high-temperature heat treatments. The first heat treatment was performed at 250°C for 10 minutes, and the second heat treatment was performed at 380°C for 30 minutes. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0103] 5.4 MEA Preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the matching CCM (SPICHE-150kW-CCM) was used to prepare the membrane electrode using a mature membrane electrode preparation process.

[0104] 5.5 Single Cell Assembly and Testing: The above membrane electrode assembly was used to assemble a single cell, and the cell performance was tested using a fuel cell testing system. The test conditions were as follows: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0105] Example 6

[0106] 6.1 MPL slurry preparation:

[0107] 1) Specific steps for the first slurry: First, add 200 parts by weight of ultrapure water, 10 parts by weight of Triton-X100 and 18 parts by weight of Cabot XC-72R and ball mill for 2 hours at 500 r / min to form a slurry. Then, add 12 parts by weight of PTFE emulsion and magnetically stir for 30 minutes at 300 r / min to obtain the first slurry.

[0108] 2) Specific steps for the second slurry: First, add 2 parts by weight of sodium dodecylbenzenesulfonate, 4 parts by weight of γ-MnO2 water electrolysis catalyst, and 100 parts by weight of water. Ball mill for 2 hours at a speed of 1000 r / min to obtain the first mixed slurry.

[0109] Then, 15 parts by weight of Cabot XC-72R, 5 parts by weight of carbon nanofibers, 2 parts by weight of PMMA nanopowder, 200 parts by weight of water and 5 parts by weight of FC4430 were ball-milled for 2 hours at a speed of 500 r / min to obtain a second mixed slurry.

[0110] First, 135 parts by weight of the second mixed slurry were added to the first mixed slurry and ball-milled for 30 minutes at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry were added to the mixture of the first mixed slurry and part of the second mixed slurry and ball-milled for 2 hours at 500 r / min to form the third mixed slurry. Finally, 10 parts by weight of PTFE emulsion were added to the third mixed slurry in two batches and magnetically stirred for 30 minutes at 300 r / min respectively to obtain the second slurry.

[0111] 6.2 Coating of MPL slurry: The first slurry was coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form a first coating layer with a thickness of 30 μm. The second slurry was then coated onto the first coating layer using a slot extrusion coating method, and then baked at 80°C for 10 min to form a second coating layer. The γ-MnO2 loading in the second coating layer was approximately 15 μg / cm³. 2 ;

[0112] 6.3 GDL Heat Treatment: The coated layer is subjected to two high-temperature heat treatments. The first heat treatment temperature is 250℃ and the heat treatment time is 10 min; the second heat treatment temperature is 380℃ and the heat treatment time is 30 min. The first coating layer forms a first microporous layer, and the second coating layer forms a second microporous layer, thus obtaining the anti-reverse polarity gas diffusion layer.

[0113] 6.4 MEA Preparation: The prepared GDL was used as the anode GDL, the cathode GDL-28BC (SGL Company), and the matching CCM (SPICHE-150kW-CCM) was used to prepare the membrane electrode using a mature membrane electrode preparation process.

[0114] 6.5 Single Cell Assembly and Testing: Assemble the above membrane electrode assembly into a single cell and use a fuel cell testing system to test the cell performance. Test conditions: cell temperature: T = 80℃, humidity: RH = 40% / 40%, back pressure: BP = 100kpa / 100kpa, excess coefficient: STO = 1.5 / 2.0.

[0115] Comparative Example 1

[0116] The single-cell preparation process of Comparative Example 1 is exactly the same as that of Example 1, except that in step 1.1 2), no γ-MnO2 water electrolysis catalyst is added during the preparation of the first mixed slurry. The loading of γ-MnO2 in the coating layer is 0.

[0117] Comparative Example 2

[0118] The single-cell preparation process of Comparative Example 2 is exactly the same as that of Example 1, except that in step 1.1 2), 4 parts by weight of γ-MnO2 water electrolysis catalyst are replaced with 4 parts by weight of IrO2 water electrolysis catalyst during the preparation of the first mixed slurry. The IrO2 loading in the second coating layer is approximately 15 μg / cm³. 2 .

[0119] Comparative Example 3

[0120] The preparation process of the single cell in Comparative Example 3 is exactly the same as that in Example 1, except that in step 1.1 2), 4 parts by weight of γ-MnO2 water electrolysis catalyst are replaced with 4 parts by weight of RuO2 water electrolysis catalyst during the preparation of the first mixed slurry. The RuO2 loading in the second coating layer is approximately 15 μg / cm³. 2 .

[0121] Comparative Example 4

[0122] The single-cell preparation process of Comparative Example 4 is exactly the same as that of Example 1, except that in step 1.1 2), after obtaining the second slurry, the second slurry is mixed with the first slurry to form an MPL slurry; in step 1.2, the MPL slurry obtained by mixing the first and second slurries is coated onto the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 20 min to form a coating layer. The γ-MnO2 loading in the coating layer is approximately 15 μg / cm³. 2 ;

[0123] Comparative Example 5

[0124] The single-cell preparation process of Comparative Example 5 is exactly the same as that of Example 1, except that in step 1.2, the second slurry is applied to the hydrophobically treated carbon paper substrate using a slot extrusion coating method, and then baked at 80°C for 10 min to form the first coating layer. The γ-MnO2 loading in the first coating layer is approximately 15 μg / cm³. 2 The first slurry was applied on top of the first coating layer using a slit extrusion coating method, and then baked at 80°C for 10 minutes to form a second coating layer with a thickness of 30 μm.

[0125] Comparative Example 6

[0126] The preparation process of the single cell in Comparative Example 6 is exactly the same as that in Example 1, except that carbon nanofibers are not added in step 1.1 2). First, 130 parts by weight of the second mixed slurry are added to the first mixed slurry and ball-milled for 30 minutes at 500 rpm. Then, the remaining 92 parts by weight of the second mixed slurry are added to the mixture of the first and part of the second mixed slurry and ball-milled for 2 hours at 500 rpm to form the third mixed slurry. The γ-MnO2 loading in the second coating layer is approximately 15 μg / cm³. 2 .

[0127] Comparative Example 7

[0128] The preparation process of the single cell in Comparative Example 7 is exactly the same as that in Example 1, except that PMMA nanopowder is not added in step 1.1 2). First, 133 parts by weight of the second mixed slurry are added to the first mixed slurry and ball-milled for 30 min at 500 r / min. Then, the remaining 92 parts by weight of the second mixed slurry are added to the mixture of the first and part of the second mixed slurry and ball-milled for 2 h at 500 r / min to form the third mixed slurry. The γ-MnO2 loading in the second coating layer is approximately 15 μg / cm³. 2 .

[0129] Table 1

[0130]

[0131] Depend on Figure 1 It can be seen that the first conductive carbon material and the first hydrophobic resin in the first microporous layer have good coating properties and strong hydrophobicity, which play a crucial role in the water vapor management of the gas diffusion layer. The second conductive carbon material (containing carbon nanofibers), PTFE emulsion and γ-MnO2 water electrolysis catalyst in the second microporous layer are uniformly dispersed and work synergistically to improve the anti-reverse polarity performance and electrical properties of the gas diffusion layer.

[0132] Depend on Figure 2 It can be seen that the surface of the anti-reverse polarity gas diffusion layer prepared in Example 1 is smooth and crack-free, and the surface of the microporous layer has a rich pore structure. The prepared gas diffusion layer can improve the surface smoothness and play the role of anti-reverse polarity.

[0133] Depend on Figure 3 As can be seen from Table 1, after 30 minutes of reverse polarization, Example 1 achieved a voltage of 1600 mA / cm. 2 The voltage drops by 13mV before and after the reverse polarity under electrical density, due to Figure 4 As shown in Table 1, after 30 minutes of reverse polarization, Comparative Example 1 achieved a voltage of 1600 mA / cm. 2 The voltage drop before and after the reverse electrode under high current density was 92mV, demonstrating the significant anti-reverse electrode effect of the gas diffusion layer in Example 1. Without the addition of a water electrolysis catalyst, the battery performance deteriorated significantly after the reverse electrode, especially with increasing current density, indicating severe performance degradation. This suggests that the reverse electrode caused corrosion and collapse of the carbon support in the catalyst layer, weakening its water vapor management capability.

[0134] As can be seen from Table 1, the anti-reverse polarity performance of Example 1 is better than that of Examples 2 and 3. The anti-reverse polarity gas diffusion layer contains a double microporous layer. The first microporous layer and the second microporous layer work together to optimize the anti-reverse polarity performance, water vapor management performance, battery performance, etc.

[0135] As can be seen from Table 1, Example 1 has better anti-reverse polarity performance than Comparative Examples 2 and 3, and has higher catalytic efficiency for water electrolysis with the same loading of γ-MnO2.

[0136] As can be seen from Table 1, the anti-reverse polarity performance of Example 1 is better than that of Comparative Examples 4 and 5. The reaction of water electrolysis mainly occurs at the contact surface between the catalyst layer and the microporous layer. In Example 1, there are more γ-MnO2 water electrolysis catalysts participating in the reaction, and the utilization rate is high.

[0137] As can be seen from Table 1, the anti-reverse polarity performance of Example 1 is better than that of Comparative Examples 6 and 7. PMMA nanopowder and the third surfactant jointly promote the dispersion of carbon nanofibers in the second coating layer. The surface of the prepared anti-reverse polarity gas diffusion layer is smooth and crack-free. After heat treatment, PMMA decomposes to generate a rich pore structure, which improves the surface smoothness of the microporous layer, enhances the electrical properties of the anti-reverse polarity gas diffusion layer, and improves the anti-reverse polarity capability.

[0138] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0139] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A method for producing an anti-reverse-mitigation gas diffusion layer, characterized by, The method comprises the following steps: (1) mixing the first solvent, the first surfactant and the first conductive carbon material uniformly, then adding the first hydrophobic resin, and mixing uniformly to obtain a first slurry; (2) mixing the second solvent, the second surfactant and the γ-MnO2 electrolytic water catalyst uniformly to obtain a first mixed slurry; mixing the third solvent, the third surfactant, the second conductive carbon material and PMMA nano powder uniformly to obtain a second mixed slurry; adding the second mixed slurry into the first mixed slurry, mixing uniformly to obtain a third mixed slurry, and adding PTFE emulsion into the third mixed slurry, mixing uniformly to obtain a second slurry; (3) coating the first slurry on a carbon substrate, drying to form a first coating layer, coating the second slurry on the first coating layer, drying to obtain a second coating layer, and then performing heat treatment, so that the first coating layer forms a first microporous layer and the second coating layer forms a second microporous layer, thereby obtaining the anti-reverse gas diffusion layer; In the step (3), the loading of γ-MnO2 in the second coating layer is 7.5-35 μg / cm2 2 ; in the step (3), the thickness of the first coating layer is 20-35 μm, and the thickness of the second coating layer is 5-20 μm; in the step (1), the first surfactant comprises at least one of Triton-X100, Tween 60 and fatty alcohol polyoxyethylene ether; the first conductive carbon material comprises at least one of XC-72R, BP2000, acetylene black, Ketjen black, graphite powder and expanded graphite; the first hydrophobic resin comprises at least one of PTFE emulsion, fluorinated ethylene propylene copolymer and polyvinylidene fluoride; and the mass ratio of the first surfactant, the first conductive carbon material and the first hydrophobic resin is 0.1-1:0.1-10:0.1-2; in the step (2), the second surfactant comprises at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide and sodium lauroyl-N-methyl aminoacetate; the second conductive carbon material comprises carbon nanofiber and at least one of acetylene black, XC-72R, BP2000, graphite powder and Ketjen black; the third surfactant comprises at least one of Triton-X100, Tween 60, FC4430 or AEO-9; the content of carbon nanofiber in the second conductive carbon material is not less than 2 wt%; and the mass ratio of the second surfactant, the γ-MnO2 electrolytic water catalyst, the third surfactant, the second conductive carbon material, PMMA nano powder and PTFE emulsion is 0.1-1:0.5-5:0.1-1:0.7-14:0.1-2:0.1-2.

2. The method for producing an anti-cathode gas diffusion layer according to claim 1, characterized by, In the step (3), the loading of γ-MnO2 in the second coating layer is 15-30 μg / cm2. 2 .

3. The method for producing an anti-cathode gas diffusion layer according to claim 1, characterized by, in the step (1), the first solvent comprises at least one of water, isopropyl alcohol, n-propanol, ethanol and n-butanol.

4. The method for producing an anti-reverse-mitosis gas diffusion layer according to claim 1, characterized by, in the step (2), the second solvent comprises at least one of water, isopropyl alcohol, n-propanol, ethanol and n-butanol; and the third solvent comprises at least one of water, isopropyl alcohol, n-propanol, ethanol and n-butanol.

5. The method for producing an anti-reverse-mitigation gas diffusion layer according to claim 1, characterized by, In the step (3), the heat treatment comprises a first heat treatment and a second heat treatment, the temperature of the first heat treatment is 200-250℃, the time of the first heat treatment is 5-15min, the temperature of the second heat treatment is 350-400℃, and the time of the second heat treatment is 10-30min.

6. An anti-kathode gas diffusion layer characterized by, The preparation method of any one of claims 1-5 is adopted to prepare.

7. A membrane electrode characterized by, The anti-reverse gas diffusion layer of claim 6 is adopted as an anode gas diffusion layer.

8. A fuel cell characterized by comprising: The membrane electrode of claim 7 is included.

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