CN114725420B - Gas diffusion layer, preparation method thereof, membrane electrode assembly and fuel cell - Google Patents
Gas diffusion layer, preparation method thereof, membrane electrode assembly and fuel cell Download PDFInfo
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- CN114725420B CN114725420B CN202210461860.XA CN202210461860A CN114725420B CN 114725420 B CN114725420 B CN 114725420B CN 202210461860 A CN202210461860 A CN 202210461860A CN 114725420 B CN114725420 B CN 114725420B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0241—Composites
- H01M8/0245—Composites in the form of layered or coated products
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/8807—Gas diffusion layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0232—Metals or alloys
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
The invention relates to a gas diffusion layer and a preparation method thereof, and a membrane electrode assembly and a fuel cell, wherein the gas diffusion layer comprises a metal mesh substrate, a composite plating layer is arranged on the metal mesh substrate, and a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in meshes of the metal mesh substrate; the composite coating comprises metal and a first hydrophobic agent, and the roughness of the composite coating is 5-8 mu m; the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2-2 μm. The gas diffusion layer has lower resistivity, higher power density and better mechanical durability.
Description
Technical Field
The present invention relates to the field of fuel cells, and in particular, to a gas diffusion layer, a method for manufacturing the same, a membrane electrode assembly, and a fuel cell.
Background
The fuel cell has the characteristics of high energy density, high energy conversion rate, environmental protection and wide application, wherein the proton exchange membrane fuel cell has the advantages of low working temperature, high starting speed, high energy conversion efficiency and the like, and has wide application prospect in new energy automobiles. The proton exchange membrane fuel cell mainly comprises a membrane electrode and a bipolar plate, wherein the membrane electrode is a core component of the fuel cell and comprises a proton exchange membrane, a catalytic layer, a frame and a gas diffusion layer which are sequentially laminated.
In order to increase the power density of the fuel cell stack, bipolar plates are gradually developed from graphite bipolar plates to metallic bipolar plates. Compared with a graphite bipolar plate electric pile, the metal bipolar plate electric pile has larger loading pressure, and the gas diffusion layer is used as a supporting component of the membrane electrode of the proton exchange membrane fuel cell and needs to bear larger pressure. The traditional gas diffusion layer is formed by directly coating a carbon substrate with a coating containing a carbon material and a hydrophobic material, wherein the internal structure of the gas diffusion layer is damaged under a relatively high pressure, and a hydrophobic film arranged on the surface of the substrate is cracked and falls off; or the carbon material is broken or fractured, and the breakage or fracture of the carbon material can lead to the shedding of the hydrophobic layer; in the fuel cell system, the reaction gas has high speed in the flow channel, and the gas and water rub on the surface of the gas diffusion layer, so that the hydrophobic layer film on the surface of the gas diffusion layer can be cracked and shed due to the friction. Damage to the hydrophobic membrane reduces the hydrophobicity of the pores within the gas diffusion layer, resulting in local liquid water accumulation in the gas diffusion layer, impeding water vapor transport of the cell, increasing diffusion polarization loss of the cell, and thus affecting the performance of the fuel cell.
Therefore, it is important to provide a gas diffusion layer having high mechanical durability.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a gas diffusion layer with better mechanical durability, a preparation method thereof, a membrane electrode assembly and a fuel cell. The method comprises the following steps:
the gas diffusion layer comprises a metal mesh substrate, wherein a composite plating layer is arranged on the metal mesh substrate, and a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in mesh holes of the metal mesh substrate;
wherein the composite coating comprises metal and a first hydrophobizing agent, and the roughness of the composite coating is 5-8 mu m; the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2-2 mu m.
The gas diffusion layer provided by the invention is characterized in that a metal mesh substrate is provided with a composite plating layer containing specific substances, and metal in the composite plating layer is tightly combined with the metal mesh substrate; the binding force between the first hydrophobic layer and the second hydrophobic layer which are arranged at different heights along the axial direction in the mesh of the metal mesh substrate and the composite coating can be effectively improved by controlling the roughness of the composite coating; and is provided with a metal mesh substrate and a first composite plating layer containing specific substances The hydrophobic layer and the second hydrophobic layer are combined into an organic whole, so that the binding force between the metal mesh substrate provided with the composite coating containing specific substances and the first hydrophobic layer and the second hydrophobic layer is effectively improved, and the mechanical durability such as compression resistance, scouring resistance and the like of the gas diffusion layer is effectively improved. Meanwhile, when water generated by the proton transfer reaction contacts the second metal layer, the water is subjected to water retention management on the second metal layer; when the volume of water generated by the proton transfer reaction increases, the water overflows to the second hydrophobic layer, and water is drained at the moment, so that the water management of the gas diffusion layer is realized, the water vapor transfer of the cell is effectively prevented from being blocked, and the performance of the fuel cell is effectively maintained. The power density is 1190-1430W/cm 2 After the mechanical gas scouring resistance attenuation test, the mass change rate of the gas diffusion layer is only 0.01-0.24%, and the power density change rate is only 0.3-4.6%.
In addition, the partial area of the metal mesh substrate is not provided with a hydrophobic coating, so that the influence of the hydrophobic material on conductivity is effectively prevented.
The gas diffusion layer is free of carbon materials, so that the problem of carbon corrosion caused by gradual rising of the working voltage design of the membrane electrode is effectively avoided, and the membrane electrode has good stability under high voltage conditions caused by frequent start and stop working conditions.
In some of these embodiments, the pore size of the first hydrophobic layer is from 0.1 μm to 50 μm and the pore size of the second hydrophobic layer is from 5nm to 500nm in the gas diffusion layer.
In some of these embodiments, the pore size of the first metal layer and the pore size of the second metal layer are each independently 0.5 μm to 100 μm in the gas diffusion layer.
In some of these embodiments, in the gas diffusion layer, the first hydrophobic layer comprises a second hydrophobic agent, and the second hydrophobic layer comprises a third hydrophobic agent; the first hydrophobic agent comprises the second hydrophobic agent and the third hydrophobic agent.
In some of these embodiments, the thickness of the composite plating layer in the gas diffusion layer is 5 μm to 10 μm.
In some of these embodiments, the ratio of the heights of the first hydrophobic layer to the second hydrophobic layer in the axial direction within the mesh of the expanded metal substrate is (2-5): 1.
In some of these embodiments, the height of the first hydrophobic layer is 50 μm to 400 μm and the height of the second hydrophobic layer is 10 μm to 100 μm in the gas diffusion layer.
In some embodiments, the metal mesh substrate is made of at least one material selected from nickel, iron, silver, titanium, gold, platinum and palladium.
In some of these embodiments, the mesh structure of the metal mesh substrate is selected from one of a sintered felt, a punched mesh, a woven mesh, a stretched mesh, a laser perforated mesh, a wire cut mesh, a powder metallurgy mesh, a casting mesh, an injection molded mesh, or a foam mesh.
In some of these embodiments, the metal is selected from at least one of titanium, chromium, molybdenum, and nickel in the gas diffusion layer.
In some of these embodiments, the first hydrophobic agent is selected from at least one of polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, copolymers of tetrafluoroethylene and hexafluoropropylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether.
The invention also provides a preparation method of the gas diffusion layer, which comprises the following steps:
providing a metal mesh substrate with a composite plating layer, wherein the composite plating solution comprises metal and a first hydrophobizing agent, and the roughness of the composite plating layer is 5-8 mu m;
coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating, after sintering, coating a second hydrophobic slurry on the other side of the metal mesh substrate, which is away from the side coated with the first hydrophobic slurry, and sintering to obtain a gas diffusion layer precursor;
Carrying out surface treatment on the precursor of the gas diffusion layer to obtain the gas diffusion layer; the first metal layer, the first hydrophobic layer, the second hydrophobic layer and the second metal layer are sequentially arranged at different positions in the mesh of the metal mesh substrate in the gas diffusion layer along the axial direction, and the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2-2 mu m.
In some embodiments, in the preparation method of the gas diffusion layer, the first hydrophobic slurry comprises the following components in parts by weight:
the second hydrophobic slurry comprises the following components:
the invention provides a membrane electrode assembly, which comprises a proton exchange membrane, a catalytic layer, a frame and the gas diffusion layer which are sequentially laminated.
The invention provides a fuel cell, which comprises an anode plate, a cathode plate and the membrane electrode assembly, wherein the anode plate and the cathode plate are arranged on two sides of the membrane electrode assembly.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a front view of a gas diffusion layer according to one embodiment;
wherein the marks are as follows:
10: a gas diffusion layer; 11: a first metal layer; 12: a first hydrophobic layer; 13: a second hydrophobic layer; 14: a second metal layer.
Detailed Description
The technical scheme of the invention is further described in detail below with reference to specific embodiments. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
The weights of the relevant components mentioned in the description of the embodiments of the present invention may refer not only to the specific contents of the components, but also to the proportional relationship between the weights of the components, so long as the contents of the relevant components in the description of the embodiments of the present invention are scaled up or down within the scope of the disclosure of the embodiments of the present invention. Specifically, the weight described in the specification of the embodiment of the present invention may be mass units known in the chemical industry field such as μ g, mg, g, kg.
Referring to fig. 1, an embodiment of the present invention provides a gas diffusion layer 10, which includes a metal mesh substrate, on which a composite plating layer is disposed, wherein a first metal layer 11, a first hydrophobic layer 12, a second hydrophobic layer 13 and a second metal layer 14 are sequentially disposed at different heights along an axial direction in a mesh of the metal mesh substrate;
wherein the composite coating comprises metal and a first hydrophobic agent, and the roughness of the composite coating is 5-8 mu m; the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2-2 μm.
By arranging a composite plating layer containing specific substances on the metal mesh substrate, the metal in the composite plating layer is tightly combined with the metal mesh substrate; the binding force between the first hydrophobic layer and the second hydrophobic layer which are arranged at different heights along the axial direction in the mesh of the metal mesh substrate and the composite coating can be effectively improved by controlling the roughness of the composite coating; and the composite plating metal net substrate containing the specific substances is combined with the first hydrophobic layer and the second hydrophobic layer to form an organic whole, so that the binding force of the composite plating metal net substrate containing the specific substances with the first hydrophobic layer and the second hydrophobic layer is effectively improved, and the mechanical durability such as compression resistance, scouring resistance and the like of the gas diffusion layer is effectively improved. Meanwhile, when water generated by the proton transfer reaction contacts the second metal layer, the water is subjected to water retention management on the second metal layer; when the volume of water generated by the proton transfer reaction increases, the water overflows to the second hydrophobic layer, and water is drained at the moment, so that the water management of the gas diffusion layer is realized, the water vapor transfer of the cell is effectively prevented from being blocked, and the performance of the fuel cell is effectively maintained. In addition, the partial area of the metal mesh substrate is not provided with a hydrophobic coating, so that the influence of the hydrophobic material on conductivity is effectively prevented.
It is understood that the roughness of the composite plating layer may be 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, or the like. The roughness of the composite coating is too small, so that the binding force of the metal mesh substrate with the first hydrophobic layer and the second hydrophobic layer is affected, and the surface roughness is too large, so that the corrosion resistance of the metal layer is affected.
It is further understood that the heights of the first metal layer and the second metal layer in the axial direction within the mesh of the metal mesh substrate may be the same or different; it is further understood that the heights of the first metal layer and the second metal layer in the axial direction within the mesh of the metal mesh substrate may be 0.5 μm, 0.9 μm, 1 μm, 1.5 μm, 2 μm, or the like, respectively, independently. Optionally, the first metal layer and the second metal layer have a height of 0.5 μm to 2 μm in the axial direction within the mesh of the metal mesh substrate.
The height of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction can be controlled, so that the water pipe of the gas diffusion layer can be further lifted. When the height of the metal layer is smaller, water in the catalytic layer is easy to contact with the hydrophobic layer, so that the water drainage process can be started, and the water retention of the catalytic layer under the low-humidity condition is not facilitated; when the height of the metal layer is larger, water in the catalytic layer is not easy to contact with the hydrophobic layer, and drainage of the catalytic layer is hindered.
In some examples, the gas diffusion layer includes a first hydrophobic layer including a first hydrophobic agent and a second hydrophobic layer including a second hydrophobic agent; wherein the first hydrophobizing agent comprises a second hydrophobizing agent and a third hydrophobizing agent.
The first hydrophobic agent and the second hydrophobic agent in the composite coating and the third hydrophobic agent in the second hydrophobic layer are combined into a whole in the sintering and curing process by controlling the first hydrophobic agent to contain the second hydrophobic agent and the third hydrophobic agent, so that the binding force of the metal mesh substrate and the first hydrophobic layer and the second hydrophobic layer is further improved, and the mechanical durability such as compression resistance, scouring resistance and the like of the gas diffusion layer is further improved.
In some examples, the gas diffusion layer has a pore size of 0.1 μm to 120 μm in the first hydrophobic layer and a pore size of 2nm to 500nm in the second hydrophobic layer.
It is understood that the pore size of the first hydrophobic layer may be 0.1 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc.; the pore size of the second hydrophobic layer may be 2nm, 5nm, 10nm, 20nm, 35nm, 50nm, 80nm, 90nm, 100nm, 150nm, 170nm, 200nm, 250nm, 350nm, 450nm, 470nm, 480nm, 490nm, 500nm, etc.
Alternatively, the first hydrophobic layer has a pore size of 0.1 μm to 50 μm and the second hydrophobic layer has a pore size of 10nm to 500nm.
In the fuel cell, one side of the first hydrophobic layer faces the bipolar plate, one side of the second hydrophobic layer faces the catalytic layer, and the first hydrophobic layer and the second hydrophobic layer are arranged to be of a gradient pore diameter structure, so that water drainage is further promoted, flooding is effectively prevented, and therefore the water management of the gas diffusion layer can be improved, and the performance of the fuel cell is effectively maintained. The pore diameters of the first hydrophobic layer and the second hydrophobic layer are too large, so that the drainage speed is too high, and the water retention of the catalytic layer under the low-humidity condition is not facilitated; the aperture difference of the first hydrophobic layer and the second hydrophobic layer is too small, which is unfavorable for the drainage of the catalytic layer, and is easy to cause flooding, and the performance of the fuel cell is affected.
In some examples, in the gas diffusion layer, the pore diameter of the first metal layer and the pore diameter of the second metal layer are each independently 0.5 μm to 230 μm; alternatively, the pore diameter of the first metal layer and the pore diameter of the second metal layer are respectively and independently 0.5 μm to 100 μm; further alternatively, the pore diameter of the first metal layer and the pore diameter of the second metal layer are each independently 5 μm to 100 μm. It will be appreciated that the pore size of the first metal layer and the pore size of the second metal layer may be the same or different; optionally, the pore size of the first metal layer is the same as the pore size of the second metal layer. It is further understood that the pore size of the first metal layer and the pore size of the second metal layer are selected from 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 50 μm, 60 μm, 80 μm, 90 μm, 100 μm, etc. It is also understood that the smaller the pore size of the first and second metal layers, the higher the cost.
By controlling the pore diameters of the first metal layer and the second metal layer, the conductive contact points of the gas diffusion layer and the catalytic layer and the bipolar plate respectively are effectively controlled, so that the resistance is controlled. When the aperture of the metal layer is bigger, the conductive contact points between the gas diffusion layer and the catalytic layer and the bipolar plate are smaller, and the surface contact resistance is larger; when the pore diameter of the metal layer is small, the cost increases.
In some examples, the thickness of the composite plating layer in the gas diffusion layer is 5 μm to 10 μm.
It is understood that the thickness of the composite plating layer may be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, or the like.
In some examples, the ratio of the heights of the first hydrophobic layer to the second hydrophobic layer in the axial direction within the mesh of the metal mesh substrate is (2-5): 1. It is understood that the ratio of the heights of the first hydrophobic layer to the second hydrophobic layer in the axial direction within the mesh of the metal mesh substrate may be 2:1, 3.3:1, 3.6:1, 4:1, 4.3:1, 5:1, etc.
Further, the ratio of the heights of the first hydrophobic layer and the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is (3.3-5): 1.
In some examples, the gas diffusion layer has a height of the first hydrophobic layer of 50 μm to 400 μm and a height of the second hydrophobic layer of 10 μm to 100 μm.
It is understood that the height of the first hydrophobic layer may be 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm or 400 μm; the height of the second hydrophobic layer may be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, etc.
In some examples, the metal mesh substrate is selected from at least one of nickel, iron, silver, titanium, gold, platinum, and palladium in the gas diffusion layer.
In some examples, the mesh structure of the metal mesh substrate in the gas diffusion layer is selected from one of a sintered felt, a punched mesh, a woven mesh, a stretched mesh, a laser-perforated mesh, a wire-cut mesh, a powder metallurgy mesh, a casting mesh, an injection-molded mesh, or a foam mesh.
The metal mesh substrate is a good conductor of heat and electricity, has the advantages of high pressure resistance, high rigidity, good permeability, controllable aperture and pore, strong processability and the like, and can enhance the strength and the heat conductivity of the gas diffusion layer and reduce the resistivity of the gas diffusion layer.
In some examples, the metal in the gas diffusion layer is selected from at least one of titanium, chromium, molybdenum, and nickel. It is understood that the metal in the composite plating layer may be one kind or two or more kinds.
In some examples, the first hydrophobic agent is selected from at least one of polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, copolymers of tetrafluoroethylene and hexafluoropropylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether.
The second hydrophobizing agent and the third hydrophobizing agent are each independently selected from at least one of polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, a copolymer of tetrafluoroethylene and hexafluoropropylene, and a copolymer of tetrafluoroethylene and a perfluoroalkyl vinyl ether.
It will be appreciated that one of them may be selected, or two or more thereof may be selected, for example, a combination of polytetrafluoroethylene and polytrifluoroethylene, a combination of polytrifluoroethylene and polyvinylidene fluoride, a combination of polyvinylidene fluoride and tetrafluoroethylene, a combination of polytetrafluoroethylene, polytrifluoroethylene and polyvinylidene fluoride.
An embodiment of the present invention provides a method for manufacturing a gas diffusion layer, including steps S10 to S30.
It will be appreciated that the method of preparing a gas diffusion layer provided by the present invention may be used to explain the gas diffusion layer described above.
Step S10: providing a metal net with a composite plating layer, wherein the composite plating solution comprises metal and a first hydrophobizing agent, and the roughness of the composite plating layer is 5-8 mu m.
In some examples, in step S10, the metal mesh with the composite plating layer may be obtained by electroplating the metal base mesh with a composite electroplating solution.
In some examples, in step S10, the process flow of electroplating includes a third solvent degreasing process, a water washing process, an electroplating process, a water washing process, and a drying process.
In some examples thereof, in step S10, the third solvent in the degreasing process is selected from at least one of gasoline, kerosene, trichloroethylene, carbon tetrachloride, and ethanol.
In some examples, in step S10, the electroplating process includes the steps of:
the anode is used as a nickel plate, the cathode is used as a metal net, and the current density is 2A/dm 2 ～6A/dm 2 Stirring at 40-60 deg.c for 0.5-3 hr.
It will be appreciated that the current density may be 2A/dm 2 、2.5A/dm 2 、3A/dm 2 、3.5A/dm 2 、4A/dm 2 、4.5A/dm 2 、5A/dm 2 、5.5A/dm 2 Or 6A/dm 2 Etc.; the temperature can be 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃ or the like; the stirring time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, etc.
In some examples, in step S10, the plating solution used in the plating process includes a metal sulfate, a metal chloride, a first hydrophobizing agent, H 3 BO 3 1, 4-butynediol, sodium dodecyl sulfate, sodium citrate, cationic surfactant and water.
In some examples, in step S10, the plating solution includes the following components in parts by weight:
it will be appreciated that the parts of metal sulfate may be 15 parts, 20 parts, 25 parts, 30 parts, etc., the parts of metal chloride may be 3 parts, 4 parts, 5 parts, 6 parts, etc., the parts of the first hydrophobe may be 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc., H 3 BO 3 The parts of (a) may be 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, etc., the parts of 1, 4-butynediol may be 0.02 parts, 0.04 parts, 0.08 parts, 0.12 parts, 0.16 parts, 0.2 parts, etc., the parts of sodium dodecyl sulfate may be 0.02 parts, 0.04 parts, 0.06 parts, 0.08 parts, 0.1 parts, etc., the parts of sodium citrate may be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc., and the parts of the cationic surfactant may be 0.01 parts, 0.03 parts, 0.05 parts, 0.07 parts, 0.09 parts, 0.1 parts, etc.
In other examples, in step S10, the plating solution includes the following components in mass percent:
in some examples, in step S10, the metal in the metal sulfate and the metal chloride are each independently selected from at least one of titanium, chromium, molybdenum, and nickel.
In some examples, in step S10, the pH of the plating solution is 3 to 4.
It is understood that the pH of the plating solution may be 3, 3.2, 3.4, 3.6, 3.8, 4, etc.
In some examples, in step S10, stirring may be performed using mechanical stirring or ultrasonic dispersion.
In some examples, in step S10, the conditions of the drying process are: drying for 0.5-5 h at 350-1000 ℃ under nitrogen and/or inert gas atmosphere.
It is understood that the drying temperature may be 350 ℃, 400 ℃, 500 ℃, 550 ℃, 700 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃ or the like, and the drying time may be 0.5h, 0.8h, 1h, 2h, 3h, 4h, 5h or the like.
Step S20: and coating a first hydrophobic slurry on one side of the metal mesh with the composite coating, coating a second hydrophobic slurry on the other side of the metal mesh, which is away from the metal mesh coated with the first hydrophobic slurry, after sintering, and sintering to obtain the precursor of the gas diffusion layer.
In some examples, the method for preparing the gas diffusion layer includes the following components in parts by weight:
the pore sizes of the first hydrophobic layer and the second hydrophobic layer can be controlled by controlling the components and the specific proportion in the first hydrophobic slurry and the second hydrophobic slurry respectively.
It is understood that the first pore-forming agent may be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc., the first dispersant may be 0.1 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, etc., the first hydrophobic agent may be 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, etc., the first solvent may be 43 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 71 parts, etc., the second pore-forming agent may be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc., the second dispersant may be 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, etc., and the second hydrophobic agent may be 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 75 parts, 80 parts, etc., and the second solvent may be 80 parts, etc.
In other examples, the method of making the gas diffusion layer, in mass percent, the first hydrophobic slurry comprises the following components:
the second hydrophobic slurry comprises the following components:
in some examples, in step S20, the first pore-forming agent and the second pore-forming agent are each independently selected from at least one of an inorganic pore-forming agent and an organic pore-forming agent.
In some examples, in step S20, the inorganic pore-forming agent is selected from the group consisting of calcium carbonate, sodium bicarbonate, and SiO 2 At least one of the aerogels.
In some examples, in step S20, the organic pore-forming agent is selected from at least one of urea, polymethyl methacrylate, and t-butanol.
In some examples thereof, in step S20, the first dispersant and the second dispersant are each independently selected from at least one of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.
In some examples thereof, in step S20, the second hydrophobic agent and the third hydrophobic agent are each independently selected from at least one of polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, copolymers of tetrafluoroethylene and hexafluoropropylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether.
In some examples thereof, in step S20, the first solvent and the second solvent are each independently selected from at least one of water, methanol, ethanol, isopropanol, ethylene glycol, butylene glycol, glycerol, acetone, and diethyl ether.
In some examples, in step S20, the coating is performed by knife coating, spray coating, brush coating, print coating, screen printing, or suction filtration.
In some examples, in step S20, the sintering temperature is 350 to 1000 ℃ and the sintering time is 0.5 to 5 hours.
It is understood that the sintering temperature may be 350 ℃, 400 ℃, 500 ℃, 550 ℃, 700 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃ or the like, and the sintering time may be 0.5h, 0.8h, 1h, 2h, 3h, 4h, 5h or the like.
In some of these examples, in step S20, sintering is performed under nitrogen and/or inert gas atmosphere.
Step S30: performing surface treatment on the gas diffusion layer precursor obtained in the step S20 to obtain a gas diffusion layer; the first metal layer, the first hydrophobic layer, the second hydrophobic layer and the second metal layer are sequentially arranged at different positions in the mesh of the metal mesh substrate in the gas diffusion layer along the axial direction, and the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2-2 mu m.
It is understood that the surface treatment is to remove the coating deposited on the surface of the metal mesh substrate after sintering the first hydrophobic slurry and the second hydrophobic slurry, and the coating partially deposited in the mesh, the area of the mesh from which the coating is removed is the first metal layer and the second metal layer, the area from which the first hydrophobic slurry is deposited is the first hydrophobic layer, and the area from which the second hydrophobic slurry is deposited is the second hydrophobic layer, i.e., the first metal layer and the second metal layer do not contain the coating after sintering the first hydrophobic slurry and the second hydrophobic slurry.
In some examples, in step S30, the gas diffusion layer precursor is surface treated with a polishing, shot blasting, or sodium naphthalene treatment solution surface treatment.
An embodiment of the present invention provides a membrane electrode assembly, including a proton exchange membrane, a catalytic layer, a frame, and the gas diffusion layer, which are sequentially stacked.
An embodiment of the present invention provides a fuel cell, including an anode plate, a cathode plate, and the membrane electrode assembly described above, where the anode plate and the cathode plate are disposed on two sides of the membrane electrode assembly.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
The following examples of the gas diffusion layer and the method of manufacturing the same, and the membrane electrode assembly and the fuel cell according to the present invention, it is to be understood that the gas diffusion layer and the method of manufacturing the same, and the membrane electrode assembly and the fuel cell according to the present invention are not limited to the following examples.
Example 1
(1) Electroplating the powder metallurgy net of the iron by adopting a gasoline degreasing process, a water washing process, a composite electroplating process, a water washing process and a drying process (nitrogen atmosphere and drying at 1000 ℃ for 0.5 h) in sequence; wherein, in the composite electroplating process, the electroplating solution comprises the following components in percentage by mass: 15wt% of titanium sulfate, 4wt% of titanium chloride, 4wt% of a first hydrophobizing agent (polytetrafluoroethylene and polytrifluoroethylene) and H 3 BO 3 3.6wt%, 1, 4-butynediol 0.15wt%, sodium dodecyl sulfate 0.06wt%, sodium citrate 2wt%, cationic surfactant (octadecyl ammonium acetate) 0.03wt%, and water for the rest; the pH value of the electroplating solution is 3.9; powder metallurgy net with anode as nickel plate and cathode as iron, current density of 6A/dm 2 Stirring for 3 hours at 40 ℃ to obtain a metal mesh substrate with a composite coating;
(2) Coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating layer prepared in the step (1), and sintering at 800 ℃ for 1.5 hours; coating a second hydrophobic slurry on the other side of the metal mesh substrate, which faces away from the first hydrophobic slurry, and sintering at 1000 ℃ for 0.5h; wherein, the first hydrophobic sizing agent is as follows by mass percent: 10wt% of calcium carbonate, 1wt% of polyethylene glycol, 25wt% of polytetrafluoroethylene and the balance of water; the second hydrophobic slurry is: 4wt% of sodium bicarbonate, 1.5wt% of polyethylene glycol, 16wt% of polytrifluoroethylene and the balance of water;
(3) Polishing to remove the first hydrophobic slurry and the second hydrophobic slurry after sintering on part of the metal mesh substrate to obtain a gas diffusion layer;
in the gas diffusion layer prepared in example 1, a composite plating layer containing titanium, polytetrafluoroethylene and polytrifluoroethylene is arranged on the surface of a metal mesh substrate, and a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in the mesh of the metal mesh substrate, wherein the roughness of the composite plating layer is 5 μm, and the thickness of the composite plating layer is 5 μm; the aperture of the first metal layer is 5-10 mu m, and the height of the first metal layer in the mesh of the metal mesh substrate along the axial direction is 0.5 mu m; the aperture of the first hydrophobic layer is 1-3 mu m, and the height of the first hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 50 mu m; the aperture of the second hydrophobic layer is 10 nm-20 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 10 mu m; the second metal layer has a pore diameter of 5 μm to 10 μm and a height in the axial direction within the mesh of the metal mesh substrate of 0.5 μm.
Example 2
(1) Electroplating the stretched net of iron by adopting a gasoline degreasing process, a water washing process, a composite electroplating process, a water washing process and a drying process (nitrogen atmosphere, and drying at 900 ℃ for 0.5 h) in sequence; wherein, in the composite electroplating process, the electroplating liquid comprises the following components in percentage by mass: 20% by weight of chromium sulfate, 5% by weight of chromium chloride, 2% by weight of a first hydrophobizing agent (copolymer of polyvinylidene fluoride and tetrafluoroethylene with hexafluoropropylene), H 3 BO 3 4.2wt%, 1, 4-butynediol 0.2wt%, sodium dodecyl sulfate 0.08wt%, sodium citrate 3wt%, anionic surfactant (sodium alkylaryl sulfonate) 0.1wt%, and water for the rest; the pH value of the electroplating solution is 3.7; the anode is used as a nickel plate, the cathode is used as a stretched net of iron, and the current density is 5A/dm 2 Stirring for 1.5h at 55 ℃ to obtain a metal net with a composite coating;
(2) Coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating layer prepared in the step (1), and sintering at 900 ℃ for 0.5h; coating a second hydrophobic slurry on the other side of the metal mesh substrate, which faces away from the first hydrophobic slurry, and sintering the metal mesh substrate at 800 ℃ for 4 hours; wherein, the first hydrophobic sizing agent is as follows by mass percent: siO (SiO) 2 15wt% of aerogel, 0.5wt% of alkylphenol ethoxylates, 20wt% of polyvinylidene fluoride and the balance of methanol; the second hydrophobic slurry is: 6wt% of calcium carbonate, 0.1wt% of polyethylene glycol and four kinds of calcium carbonate 8wt% of copolymer of fluoroethylene and hexafluoropropylene and the balance of ethanol;
(3) Shot blasting is carried out to remove the first hydrophobic slurry and the second hydrophobic slurry after sintering on part of the metal mesh substrate, so as to obtain a gas diffusion layer;
in the gas diffusion layer prepared in example 2, a composite plating layer containing chromium, polyvinylidene fluoride and a copolymer of tetrafluoroethylene and hexafluoropropylene is arranged on the surface of a metal mesh substrate, a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in the mesh of the metal mesh substrate, and the roughness of the composite plating layer is 6.5 μm and the thickness of the composite plating layer is 10 μm; the aperture of the first metal layer is 80-100 μm, and the height of the first metal layer in the mesh of the metal mesh substrate along the axial direction is 0.8 μm; the aperture of the first hydrophobic layer is 30-50 μm, and the height of the first hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 100 μm; the aperture of the second hydrophobic layer is 450-500 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 30 mu m; the second metal layer has a pore diameter of 80 μm to 100 μm and a height in the axial direction within the mesh of the metal mesh substrate of 2 μm.
Example 3
(1) Electroplating the titanium woven mesh sequentially by adopting a gasoline degreasing process, a water washing process, a composite electroplating process, a water washing process and a drying process (drying at 700 ℃ for 5 hours in a nitrogen atmosphere); wherein, in the composite electroplating process, the electroplating liquid comprises the following components in percentage by mass: 27wt% of titanium sulfate, 3.5wt% of titanium chloride, 9wt% of a first hydrophobizing agent (polytetrafluoroethylene, copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether), and H 3 BO 3 3.1wt%, 1, 4-butynediol 0.18wt%, sodium dodecyl sulfate 0.04wt%, sodium citrate 2.9wt%, non-ionic surfactant (polyoxyethylene ether of octyl phenol) dodecyl ammonium acetate 0.09wt% and water for the rest; the pH value of the electroplating solution is 3.5; the anode is used as a nickel plate, the cathode is used as a titanium woven net, and the current density is 5.5A/dm 2 Stirring for 2 hours at 49 ℃ to obtain a metal net with a composite coating;
(2) Coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating layer prepared in the step (1), and sintering at 700 ℃ for 5 hours; is coated on the metal mesh substrate in a deviating wayCoating the other side of the hydrophobic slurry with a second hydrophobic slurry, and sintering for 5 hours at 350 ℃; wherein, the first hydrophobic sizing agent is as follows by mass percent: 8wt% of sodium bicarbonate, 0.8wt% of alkyl glycoside, 39wt% of copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether and isopropanol balance; the second hydrophobic slurry is: siO (SiO) 2 Aerogel 1wt%, polyethylene glycol 2wt%, polytetrafluoroethylene 12wt% and butanediol balance;
(3) Shot blasting is carried out to remove the first hydrophobic slurry and the second hydrophobic slurry after sintering on part of the metal mesh substrate, so as to obtain a gas diffusion layer;
in the gas diffusion layer prepared in example 3, a composite plating layer containing titanium, polytetrafluoroethylene, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether is arranged on the surface of a metal mesh substrate, a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in the mesh of the metal mesh substrate, and the roughness of the composite plating layer is 8 μm and the thickness of the composite plating layer is 10 μm; the aperture of the first metal layer is 15-20 mu m, and the height of the first metal layer in the mesh of the metal mesh substrate along the axial direction is 2 mu m; the aperture of the first hydrophobic layer is 5-10 mu m, and the height of the first hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 400 mu m; the aperture of the second hydrophobic layer is 80 nm-100 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 100 mu m; the second metal layer has a pore diameter of 15 μm to 20 μm and a height in the axial direction within the mesh of the metal mesh substrate of 0.9 μm.
Example 4
(1) Electroplating the punching net of titanium by adopting a gasoline degreasing process, a water washing process, a composite electroplating process, a water washing process and a drying process (nitrogen atmosphere and drying at 350 ℃ for 3 hours) in sequence; wherein, in the composite electroplating process, the electroplating liquid comprises the following components in percentage by mass: 19wt% of molybdenum sulfate, 3wt% of molybdenum trichloride, 0.5wt% of a first hydrophobizing agent (polytrifluoroethylene and polytetrafluoroethylene) and H 3 BO 3 3wt%, 1, 4-butynediol 0.02wt%, sodium dodecyl sulfate 0.02wt%, sodium citrate 1wt%, amphoteric surfactant (alkyl dimethyl hydroxypropyl phosphate betaine) 0.01wt%, and water for the rest; the pH value of the electroplating solution is 4; punching net with anode as nickel plate and cathode as titanium, and currentDensity of 2A/dm 2 Stirring at 60 ℃ for 0.5h to obtain a metal net with a composite coating;
(2) Coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating layer prepared in the step (1), and sintering for 4 hours at 350 ℃; coating a second hydrophobic slurry on the other side of the metal mesh substrate, which faces away from the first hydrophobic slurry, and sintering the metal mesh substrate at 700 ℃ for 3 hours; wherein, the first hydrophobic sizing agent is as follows by mass percent: siO (SiO) 2 14wt% of aerogel, 0.1wt% of polyethylene glycol, 35wt% of polytrifluoroethylene and the balance of acetone; the second hydrophobic slurry is: 3wt% of sodium bicarbonate, 1wt% of polyethylene glycol, 5wt% of polytetrafluoroethylene and the balance of glycerol;
(3) Shot blasting is carried out to remove the first hydrophobic slurry and the second hydrophobic slurry after sintering on part of the metal mesh substrate, so as to obtain a gas diffusion layer;
in the gas diffusion layer prepared in example 4, a composite plating layer containing molybdenum, polytrifluoroethylene and polytetrafluoroethylene is arranged on the surface of a metal mesh substrate, and a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in the mesh of the metal mesh substrate, wherein the roughness of the composite plating layer is 6 μm, and the thickness is 8 μm; the aperture of the first metal layer is 15-25 μm, and the height of the first metal layer in the mesh of the metal mesh substrate along the axial direction is 1.5 μm; the aperture of the first hydrophobic layer is 5-8 mu m, and the height of the first hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 200 mu m; the aperture of the second hydrophobic layer is 35 nm-50 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 55 mu m; the second metal layer has a pore diameter of 15 μm to 25 μm and a height in the axial direction of 1 μm in the mesh of the metal mesh substrate.
Example 5
(1) Electroplating the nickel foam net by adopting a gasoline degreasing process, a water washing process, a composite electroplating process, a water washing process and a drying process (inert gas atmosphere and drying at 1000 ℃ for 1.5 h) in sequence; wherein, in the composite electroplating process, the electroplating liquid comprises the following components in percentage by mass: 30wt% of nickel sulfate, 6wt% of nickel chloride, 10wt% of a first hydrophobizing agent (copolymer of polyvinylidene fluoride and tetrafluoroethylene and hexafluoropropylene), H 3 BO 3 5wt%, 1, 4-butynedi0.1wt% of alcohol, 0.1wt% of sodium dodecyl sulfate, 4wt% of sodium citrate, 0.05wt% of cationic surfactant (dodecyl ammonium acetate) and the balance of water; the pH value of the electroplating solution is 3; the anode is used as a nickel plate, the cathode is used as a nickel foam net, and the current density is 2.5A/dm 2 Stirring for 1h at 50 ℃ to obtain a metal net with a composite coating;
(2) Coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating layer prepared in the step (1), and sintering at 1000 ℃ for 3 hours; coating a second hydrophobic slurry on the other side of the metal mesh substrate, which faces away from the first hydrophobic slurry, and sintering at 900 ℃ for 1.5h; wherein, the first hydrophobic sizing agent is as follows by mass percent: 12% by weight of calcium carbonate, 2% by weight of polydimethyl guanidine salt, 40% by weight of copolymer of tetrafluoroethylene and hexafluoropropylene and the balance of butanediol; the second hydrophobic slurry is: 7wt% of calcium carbonate, 1.8wt% of alkyl glycoside, 20wt% of polyvinylidene fluoride and the balance of diethyl ether;
(3) Polishing to remove the first hydrophobic slurry and the second hydrophobic slurry after sintering on part of the metal mesh substrate to obtain a gas diffusion layer;
in the gas diffusion layer prepared in example 5, a composite plating layer containing nickel, polyvinylidene fluoride and a copolymer of tetrafluoroethylene and hexafluoropropylene is arranged on the surface of a metal mesh substrate, a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged at different heights along the axial direction in the mesh of the metal mesh substrate, and the roughness of the composite plating layer is 7 μm, and the thickness of the composite plating layer is 6 μm; the aperture of the first metal layer is 90-100 μm, and the height of the first metal layer in the mesh of the metal mesh substrate along the axial direction is 1 μm; the aperture of the first hydrophobic layer is 15-20 mu m, and the height of the first hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 300 mu m; the aperture of the second hydrophobic layer is 170 nm-200 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 70 mu m; the second metal layer has a pore diameter of 90 μm to 100 μm and a height in the axial direction within the mesh of the metal mesh substrate of 0.5 μm.
Example 6
Substantially the same as in example 1, except that the second metal layer in example 6 was 0.2 μm in height in the axial direction within the mesh of the metal mesh substrate.
Example 7
Substantially the same as in example 1, except that in example 7, the pore diameter of the first metal layer was 0.5 μm to 1 μm, and the height in the axial direction within the mesh of the metal mesh substrate was 0.5 μm; the second metal layer has a pore diameter of 0.5 μm to 1 μm and a height in the axial direction within the mesh of the metal mesh substrate of 0.5 μm.
Example 8
Substantially the same as in example 1, except that in example 8, the first metal layer had a pore diameter of 200 μm to 230 μm and a height in the axial direction within the mesh of the metal mesh substrate was 0.5 μm; the second metal layer has a pore diameter of 200 μm to 230 μm and a height in the axial direction within the mesh of the metal mesh substrate of 0.5 μm.
Example 9
Substantially the same as in example 1, except that in example 9, the pore diameter of the first hydrophobic layer was 0.1 μm to 0.15 μm, and the height in the axial direction within the mesh of the metal mesh substrate was 50 μm; the pore diameter of the second hydrophobic layer is 40 nm-50 nm, and the height of the second hydrophobic layer in the mesh of the metal mesh substrate along the axial direction is 10 mu m. The pore size difference between the first hydrophobic layer and the second hydrophobic layer was small in example 9.
Example 10
Substantially the same as in example 1, except that in example 10, the pore diameter of the first hydrophobic layer was 100 μm to 120 μm, and the height in the axial direction within the mesh of the metal mesh substrate was 50 μm; the pore diameter of the second hydrophobic layer is 2 nm-2.5 nm, and the height of the second hydrophobic layer in the axial direction in the mesh of the metal mesh substrate is 10 mu m.
The pore size difference between the first hydrophobic layer and the second hydrophobic layer was large in example 10.
Example 11
Substantially the same as in example 1, except that in step (2), polytetrafluoroethylene in the first hydrophobic slurry was replaced with an equivalent amount of polyvinylidene fluoride, and polytrifluoroethylene in the second hydrophobic slurry was replaced with an equivalent amount of copolymer of tetrafluoroethylene and hexafluoropropylene.
Comparative example 1
Substantially the same as in example 1, except that the titanium, polytetrafluoroethylene and polytrifluoroethylene composite plating layer was not provided in comparative example 1.
Comparative example 2
Substantially the same as in example 1, except that the titanium, polytetrafluoroethylene and polytrifluoroethylene composite plating layer was not provided in comparative example 2, but a titanium carbide coating layer was provided.
Comparative example 3
Substantially the same as in example 1, except that the roughness of the composite plating layer was 2 μm in comparative example 3.
Comparative example 4
Substantially the same as in example 1, except that the roughness of the composite plating layer was 15 μm in comparative example 4.
Comparative example 5
Coating a first hydrophobic slurry on one side of a carbon net, and sintering at 800 ℃ for 1.5 hours; coating a second hydrophobic slurry on the other side of the carbon net, which is away from the carbon net and is coated with the first hydrophobic slurry, and sintering the second hydrophobic slurry at 1000 ℃ for 0.5h to obtain a gas diffusion layer; wherein, the first hydrophobic sizing agent is as follows by mass percent: 10wt% of calcium carbonate, 1wt% of polyethylene glycol, 25wt% of polytetrafluoroethylene and the balance of water; the second hydrophobic slurry is: 4wt% of sodium bicarbonate, 1.5wt% of polyethylene glycol, 16wt% of polytrifluoroethylene and the balance of water.
Comparative example 6
Substantially the same as in example 1, except that in comparative example 6, step (3) was not performed, i.e., the first water-repellent layer, the second water-repellent layer, and no first metal layer and no second metal layer were sequentially provided in the height in the axial direction in the mesh of the metal mesh substrate.
Comparative example 7
Substantially the same as in example 1, except that the second metal layer in comparative example 7 was 2.5 μm in height in the axial direction within the mesh of the metal mesh substrate.
The pore diameters, thicknesses, or roughnesses of the respective layers of the gas diffusion layers prepared in the respective examples and comparative examples are shown in table 1.
TABLE 1
The gas diffusion layers prepared in each example and comparative example were used as gas diffusion layers of fuel cells, HISPEC13100 was used as catalyst, 15 μm GORE was used as proton exchange membrane, and catalyst slurry was prepared by mixing catalyst, isopropanol, deionized water and perfluorosulfonic acid type polymer solution, and coated on the proton exchange membrane with cathode platinum loading of 0.3mg/cm 2 Anode platinum loading was 0.1mg/cm 2 Assembled into single cells, and subjected to polarization curve test to obtain the power density @0.6V of the fuel cell, and the result is shown in Table 2; wherein the cell was tested at 75 ℃, cathode humidity 50%, anode humidity 40%, hydrogen/air stoichiometric ratio = 1.5/2.0, test pressure 100kPa.
Mechanical anti-gas washout decay test: after obtaining the mass and power density of the gas diffusion layers of each example and comparative example, respectively, the same two gas diffusion layers of each example and comparative example were mounted on a cell holder (without a catalytic layer and a proton exchange membrane), and a mechanical anti-gas washout attenuation test (temperature 80 ℃, air, humidity 100% rh, air flow 12L/min) was performed. Samples were taken at 30 days, tested for quality and polarization curve (assembled into single cells using gas diffusion layers after mechanical anti-gas washout decay test), and the rate of change of quality and power density before and after the test were calculated, and the results are shown in table 2.
The contact angle and the vertical resistivity of the gas diffusion layers of each of the examples and comparative examples were tested as follows:
contact angle: GB/T20042.7 proton exchange Membrane Fuel cell part 7: a carbon paper characteristic test method;
resistivity in vertical direction: GB/T20042.7 proton exchange Membrane Fuel cell part 7: a carbon paper characteristic test method;
the results are shown in Table 2.
TABLE 2
As can be seen from table 2, the gas diffusion layers prepared in the examples have lower resistivity, higher power density, and better mechanical durability than those prepared in the comparative examples; in comparative examples 1 to 2, under the working condition of high mechanical gas scouring, the metal mesh without a coating or the hydrophobic layer on the metal mesh without a composite coating is separated from the metal mesh, so that the quality of the gas diffusion layer is reduced, the metal mesh is corroded, the water management of the gas diffusion layer is affected by the separation of the hydrophobic material, the change rate of the power density is larger, and the battery performance is reduced; comparative examples 3 to 4, when the surface roughness of the metal mesh is large, the contact angle of the surface of the gas diffusion layer is reduced, thereby reducing the drainage capacity of the gas diffusion layer and affecting the water management of the gas diffusion layer; and the corrosion resistance of the gas diffusion layer is affected, the metal net is corroded, so that the change rate of the power density is large, and the battery performance is reduced; the surface roughness of the metal net is small, the binding force of the hydrophobic layer and the metal net is affected, and the hydrophobic agent falls off from the metal net after a mechanical gas scouring resistance test. Comparative example 5, replacing the metal mesh substrate with a carbon mesh and not performing step (3), wherein under the conditions of high mechanical gas impact, high temperature and high humidity, the carbon substrate is corroded, the hydrophobic material is fallen off, so that the mass change rate of the gas diffusion layer is large, and the water management of the gas diffusion layer is affected, so that the performance of the battery is reduced; in comparative example 6, the metal mesh is completely covered with the hydrophobic material without performing step (3), and when the amount of water generated by the reaction is enough to participate in proton transmission of the proton membrane, water retention management by the microporous layer is not performed when the water generated by the reaction contacts the microporous layer, resulting in degradation of the battery performance; comparative example 7, when the thickness of the second metal layer is too large, it may cause water in the catalytic layer to be less likely to contact with the hydrophobic layer, impeding drainage of the catalytic layer.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present invention, which facilitate a specific and detailed understanding of the technical solutions of the present invention, but are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. It should be understood that, based on the technical solutions provided by the present invention, those skilled in the art may obtain technical solutions through logical analysis, reasoning or limited experiments, which are all within the scope of protection of the appended claims. The scope of the patent of the invention should therefore be determined with reference to the appended claims, which are to be construed as in accordance with the doctrines of claim interpretation.
Claims (13)
1. The gas diffusion layer is characterized by comprising a metal mesh substrate, wherein a composite plating layer is arranged on the metal mesh substrate, and a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer are sequentially arranged in mesh holes of the metal mesh substrate at different heights along the axial direction;
The composite coating comprises metal and a first hydrophobizing agent, and the roughness of the composite coating is 5-8 mm; the heights of the first metal layer and the second metal layer in the mesh of the metal mesh substrate along the axial direction are respectively and independently 0.2 mm-2 mm; the aperture of the first hydrophobic layer is 0.1-50 mm, and the aperture of the second hydrophobic layer is 5-500 nm;
the preparation of the gas diffusion layer comprises the following steps:
providing a metal mesh substrate with a composite plating layer, wherein a composite plating solution for forming the composite plating layer comprises metal sulfate, metal chloride and a first hydrophobizing agent;
coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating, after sintering, coating a second hydrophobic slurry on the other side of the metal mesh substrate, which is away from the side coated with the first hydrophobic slurry, and sintering to obtain a gas diffusion layer precursor;
carrying out surface treatment on the precursor of the gas diffusion layer to obtain the gas diffusion layer; the surface treatment is to remove the coating deposited on the surface of the metal mesh substrate after the first hydrophobic slurry and the second hydrophobic slurry are sintered and the coating partially deposited in the mesh of the metal mesh substrate, wherein the area of the mesh from which the coating is removed is a first metal layer and a second metal layer respectively, so that the mesh of the metal mesh substrate in the gas diffusion layer is sequentially provided with the first metal layer, the first hydrophobic layer, the second hydrophobic layer and the second metal layer at different heights along the axial direction.
2. The gas diffusion layer according to claim 1,
the aperture of the first metal layer and the aperture of the second metal layer are respectively and independently 0.5 mm-100 mm.
3. The gas diffusion layer of claim 1, wherein the first hydrophobic layer comprises a second hydrophobic agent and the second hydrophobic layer comprises a third hydrophobic agent; the first hydrophobic agent comprises the second hydrophobic agent and the third hydrophobic agent.
4. A gas diffusion layer according to any one of claims 1 to 3, wherein the thickness of the composite coating is 5 mm to 10 mm.
5. A gas diffusion layer according to any one of claims 1 to 3, wherein the ratio of the heights of the first hydrophobic layer and the second hydrophobic layer in the axial direction within the mesh of the metal mesh substrate is (2 to 5): 1.
6. The gas diffusion layer of claim 5, wherein the first hydrophobic layer has a height of 50 mm to 400 mm and the second hydrophobic layer has a height of 10 mm to 100 mm.
7. The gas diffusion layer according to any one of claims 1 to 3 and 6, wherein the metal mesh substrate is made of at least one material selected from the group consisting of nickel, iron, silver, titanium, gold, platinum and palladium; and/or
The net-shaped structure of the metal net substrate is selected from one of a sintered felt, a punching net, a woven net, a stretching net, a laser punching net, a wire cutting net, a powder metallurgy net, a casting net, an injection molding net or a foam net.
8. The gas diffusion layer according to any one of claims 1 to 3, 6, wherein the metal is at least one selected from the group consisting of titanium, chromium, molybdenum and nickel.
9. The gas diffusion layer according to any one of claims 1 to 3 and 6, wherein the first hydrophobizing agent is at least one selected from polytetrafluoroethylene, polytrifluoroethylene, polyvinylidene fluoride, a copolymer of tetrafluoroethylene and hexafluoropropylene, and a copolymer of tetrafluoroethylene and a perfluoroalkyl vinyl ether.
10. A method of making a gas diffusion layer comprising the steps of:
providing a metal mesh substrate with a composite plating layer, wherein the composite plating solution used for forming the composite plating layer comprises metal sulfate, metal chloride and a first hydrophobizing agent, and the roughness of the composite plating layer is 5-8 mm;
coating a first hydrophobic slurry on one side of the metal mesh substrate with the composite coating, after sintering, coating a second hydrophobic slurry on the other side of the metal mesh substrate, which is away from the side coated with the first hydrophobic slurry, and sintering to obtain a gas diffusion layer precursor;
Carrying out surface treatment on the precursor of the gas diffusion layer to obtain the gas diffusion layer; the surface treatment is to remove the coating deposited on the surface of the metal mesh substrate after the first hydrophobic slurry and the second hydrophobic slurry are sintered and the coating partially deposited in the meshes of the metal mesh substrate, wherein the areas of the meshes from which the coating is removed are respectively a first metal layer and a second metal layer, so that the meshes of the metal mesh substrate in the gas diffusion layer are respectively provided with a first metal layer, a first hydrophobic layer, a second hydrophobic layer and a second metal layer at different axial heights in sequence, and the heights of the first metal layer and the second metal layer in the meshes of the metal mesh substrate are respectively and independently 0.2 mm-2 mm; the aperture of the first hydrophobic layer is 0.1-50 mm, and the aperture of the second hydrophobic layer is 5-500 nm.
11. The method of claim 10, wherein the first hydrophobic slurry comprises, in parts by weight:
8-15 parts of a first pore-forming agent;
0.1-2 parts of a first dispersing agent;
20-40 parts of a second hydrophobizing agent; a kind of electronic device with high-pressure air-conditioning system
43-71 parts of a first solvent;
the second hydrophobic slurry comprises the following components:
1-8 parts of a second pore-forming agent;
0.1-2 parts of a second dispersing agent;
5-20 parts of a third hydrophobizing agent; a kind of electronic device with high-pressure air-conditioning system
70-93 parts of a second solvent.
12. A membrane electrode assembly comprising a proton exchange membrane, a catalytic layer, a frame and a gas diffusion layer according to any one of claims 1 to 9 laminated in this order, wherein a side of the second hydrophobic layer in the gas diffusion layer faces the catalytic layer.
13. A fuel cell comprising an anode plate, a cathode plate, and the membrane electrode assembly of claim 12, the anode plate and the cathode plate being disposed on opposite sides of the membrane electrode assembly.
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| DE102016123910A1 (en) * | 2016-12-09 | 2018-06-14 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Gas diffusion electrode |
| AU2020101412A4 (en) * | 2019-07-16 | 2020-09-10 | Jiangsu University | Direct methanol fuel cell membrane electrode for improving catalyst utilization and preparation method thereof |
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| US7419546B2 (en) * | 2004-06-18 | 2008-09-02 | Basf Fuel Cell Gmbh | Gas diffusion electrodes, membrane-electrode assemblies and method for the production thereof |
| JP5300289B2 (en) * | 2008-03-12 | 2013-09-25 | キヤノン株式会社 | Gas diffusion layer, membrane electrode junction, polymer electrolyte fuel cell, and production method thereof |
| CN102082277B (en) * | 2010-12-24 | 2013-06-19 | 上海交通大学 | Metal gas diffusion layer used for fuel cell and preparation method thereof |
| CA2917305C (en) * | 2013-07-05 | 2017-08-08 | Nissan Motor Co., Ltd. | Metal gas diffusion layer for fuel cell and method for manufacturing the same |
| CN103401003B (en) * | 2013-07-17 | 2016-08-17 | 南京大学昆山创新研究院 | Gas diffusion layers of Proton Exchange Membrane Fuel Cells and preparation method thereof |
| CN104779399A (en) * | 2015-03-20 | 2015-07-15 | 中国科学院宁波材料技术与工程研究所 | Porous gas diffusion layer and preparation method thereof |
| WO2017026291A1 (en) * | 2015-08-07 | 2017-02-16 | 住友電気工業株式会社 | Metallic porous body, fuel cell, and method for manufacturing metallic porous body |
| WO2018118877A1 (en) * | 2016-12-20 | 2018-06-28 | 3M Innovative Properties Company | Electrolyzer including a porous hydrophobic gas diffusion layer |
| CN108550876A (en) * | 2018-05-22 | 2018-09-18 | 成都新柯力化工科技有限公司 | A kind of super-hydrophobic gas diffusion layers of fuel cell durability |
| CN112993265A (en) * | 2019-12-14 | 2021-06-18 | 中国科学院大连化学物理研究所 | Gas diffusion layer for fuel cell and preparation method thereof |
| CN111584909B (en) * | 2019-12-31 | 2022-04-05 | 上海嘉资新材料科技有限公司 | Gas diffusion layer, method for producing same, corresponding membrane electrode assembly and fuel cell |
| CN113675420B (en) * | 2021-08-18 | 2022-06-21 | 哈尔滨工业大学（深圳） | Gas diversion diffusion flow field plate, preparation method thereof and fuel cell |
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| AU2020101412A4 (en) * | 2019-07-16 | 2020-09-10 | Jiangsu University | Direct methanol fuel cell membrane electrode for improving catalyst utilization and preparation method thereof |
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