CN113140737A

CN113140737A - Gas diffusion layer, preparation method thereof, corresponding membrane electrode assembly and fuel cell

Info

Publication number: CN113140737A
Application number: CN202110022594.6A
Authority: CN
Inventors: 王晋
Original assignee: Shanghai Jiazi New Material Co ltd
Current assignee: Shanghai Jiazi New Material Technology Co ltd
Priority date: 2021-01-08
Filing date: 2021-01-08
Publication date: 2021-07-20
Anticipated expiration: 2041-01-08
Also published as: CN113140737B

Abstract

The invention discloses a gas diffusion layer, a preparation method thereof, a membrane electrode assembly and a fuel cell. The texture area and the residual area are prepared by a screen printing process. Therefore, the water discharge capacity of the gas diffusion layer material can be obviously improved, the gas transmission capacity is enhanced, and the performance of the fuel cell stack prepared by using the gas diffusion layer is obviously improved.

Description

Gas diffusion layer, preparation method thereof, corresponding membrane electrode assembly and fuel cell

Technical Field

The invention relates to the technical field of fuel cells, in particular to a gas diffusion layer, a preparation method, a membrane electrode assembly and a fuel cell.

Background

As an alternative energy technology, fuel cells have attracted considerable attention and continued research and development due to their characteristics of convenience in starting, high energy density, zero emission, and high energy conversion efficiency, and have been widely used as power sources for automobiles, communication base stations, portable electric tools, and the like. The power supply system for commercial use has the outstanding advantages of long enough service life and high energy density, such as application to standby power supplies, passenger vehicles, material transport vehicles, submarines and the like.

Proton exchange membrane fuel cells are the most mature, closest to commercially available fuel cells. Gas Diffusion Layers (GDLs) are important components of proton exchange membrane fuel cells, in which a Gas Diffusion Layer is located between a flow field and a catalytic Layer. The gas diffusion layer has five main functions in the membrane electrode of the proton exchange membrane fuel cell: the first step, supporting a proton exchange membrane and a catalytic layer; secondly, transmitting the cathode and anode reaction gas in the flow field flow channel to the surface of the catalyst through molecular diffusion and Knudsen; third, electrons generated from the catalytic layer are transferred to the plate. Fourthly, water produced by the catalyst layer is transmitted to the flow channel for timely removal through capillary effect, concentration diffusion and the like in the gas diffusion layer, and mass transfer polarization is avoided. Fifth, the method comprises the following steps: sometimes, the gas diffusion layer performs a function of attaching the catalyst layer, and the catalyst layer is directly coated on the surface of the gas diffusion layer.

In the proton exchange membrane fuel cell, as the electrochemical reaction gradually proceeds, water generated by the reaction accumulates near the cathode catalyst layer, and the water not only diffuses to the anode through the proton exchange membrane, but also diffuses to the cathode flow field through the cathode diffusion layer, and if the liquid water cannot be rapidly transferred, the accumulation of the water in the diffusion layer, namely, the flooding phenomenon, can be caused. Therefore, reaction gas can not be transmitted to the surface of the catalyst in time, and serious mass transfer polarization is generated, so that the performance of the battery is reduced.

From the above description, how to ensure the gas transmission balance in the fuel cell to ensure the fuel cell has better performance is a problem to be solved urgently in the fuel cell field.

Disclosure of Invention

In order to solve the problems, the technical scheme of the invention provides a gas diffusion layer, a preparation method, a membrane electrode assembly and a fuel cell, which can reduce the flooding phenomenon of the fuel cell and improve the mass transfer capacity.

In order to achieve the above problem, an embodiment of the present invention provides the following technical solutions:

a gas diffusion layer, the microporous layer of the gas diffusion layer having at least one textured area and at least one remainder area adjacent to the textured area, the textured area having a different hydrophobic agent content than the remainder area.

A method for preparing a gas diffusion layer as described above, comprising: step S11: soaking the gas diffusion layer substrate layer in a hydrophobic agent solution for one or more times, then placing the soaked gas diffusion layer substrate layer in a drying oven for heating, and finally curing the gas diffusion layer substrate layer in a high-temperature drying oven at 340-380 ℃; step S12: screen printing the gas diffusion layer substrate layer processed in the step S11 by using a screen plate with a lotus leaf texture structure or leaf texture structure pattern by using slurry with a first hydrophobic agent content, and then placing the screen plate in an oven for fully drying; step S13: screen printing the gas diffusion layer substrate processed in the step S12 by using a screen residual pattern screen plate which has the pattern of the lotus leaf texture structure or the leaf texture structure used in the step S12 and by using slurry with a second hydrophobic agent content, and then fully drying the screen residual pattern screen plate in an oven; step S14: and (4) placing the gas diffusion layer processed in the step (S13) in an oven at the temperature of 340-389 ℃ for heating, and fully volatilizing residual pore-forming agent, dispersing agent and solution.

A membrane electrode assembly, comprising: a cathode-side gas diffusion layer, a cathode-side catalyst layer, a proton exchange membrane, an anode-side catalyst layer, and an anode-side gas diffusion layer which are stacked in this order; wherein the cathode-side gas diffusion layer is prepared from a gas diffusion layer comprising the microporous layer structure as described in any one of the above; the anode-side gas diffusion layer is prepared by a gas diffusion layer comprising a microporous layer structure as described in any one of the above.

A fuel cell, comprising: the fuel cell stack is composed of the membrane electrode assembly, the polar plate, the current collecting plate, the insulating plate, the sealing structure, the end plate and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic flow chart of a method for preparing a gas diffusion layer according to an embodiment of the present invention;

FIGS. 1A and 1B are schematic diagrams of a screen pattern in a manufacturing method according to the embodiment of the invention shown in FIG. 1;

FIGS. 2A, 2B, and 2C are schematic views of several patterns of molds having lotus leaf textures or leaf textures for forming a differential distribution structure of a hydrophobizing agent according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a membrane electrode assembly according to an embodiment of the present invention;

fig. 4 is a comparison of test performance results of the unit cell prepared according to the example of the present invention and the unit cell prepared according to the conventional scheme.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In general, the basic components of a proton exchange membrane fuel cell include: polar plate, gas diffusion layer, catalyst layer and proton exchange membrane.

The electrode plate can be divided into a unipolar plate and a bipolar plate, and has the functions of separating each single cell in the cell stack, conveying fuel and oxygen to the gas diffusion layer through a channel on the electrode plate, and meanwhile, having high conductivity so as to lead current to the outside.

The gas diffusion layer, the catalyst layer and the proton exchange membrane constitute a membrane electrode assembly. The gas diffusion layer, which is one of the key materials in a pem fuel cell, is located between the catalyst layer and the plate and is the outermost layer of the mea, which provides contact between the mea and the plate, distributes the reactants to the catalyst layer, and allows the reaction product water to leave the electrode surface, allowing water to pass between the electrodes and the flow channels.

In view of the above requirements, the material for the gas diffusion layer, which is currently being used in the fuel cell in a mature state, is a porous carbon material, such as carbon paper (e.g., carbon fiber paper) or carbon cloth (e.g., carbon fiber cloth), and is coated with a microporous layer on one surface thereof. In order to improve the transport of reaction gas and liquid water in the gas diffusion layer, a hydrophobic treatment is generally performed on carbon paper or carbon cloth to construct hydrophobic gas-phase channels. And a microporous layer is coated on one surface to reduce the roughness and resistivity of the substrate. The conventional microporous layer preparation process is to apply the slurry on the surface of the substrate by a direct coating method, such as the application head of the chinese patent CN 110190295 a by adjusting the coating machine, and using different mixture slurries, each layer is uniformly applied without difference. As described in chinese patent CN 110380061 a, the microporous layer has a hydrophobic gradient in the direction perpendicular to the diffusion layer, but has no distribution difference or pattern design control difference in the horizontal direction, i.e., parallel to the surface of the substrate layer. The chinese invention patent CN 110492124 a is coated on one side of the porous conductive substrate material by one of spray coating, knife coating, spin coating, slit extrusion coating, electrostatic spinning or transfer printing, and is also a indifferent coating. The indiscriminate hydrophobic characteristic is not beneficial to absorbing water accumulated in the catalytic layer and further diffusing the water to the bipolar plate flow channel, and the hydrophobic characteristic is easy to repel the water in the microporous layer or the catalytic layer, especially under the condition of high-humidity operation condition of the fuel cell. Particularly, in the long-term operation process of the fuel cell stack, especially the operation condition of the fuel cell stack for vehicles is very complex and harsh, the operation life of tens of thousands of hours and tens of thousands of dry-wet cycles and cold-heat impacts are needed, water accumulated in the microporous layer and the catalyst layer is easy to freeze, the microporous layer and the substrate layer in the gas diffusion layer are separated due to volume expansion, a larger gap space is generated, liquid water is accumulated at the position, local flooding is caused, reaction gas is prevented from diffusing to the surface of the catalyst, mass transfer polarization is caused, local reverse polarity is caused, and finally the electrode voltage of the membrane electrode or perforation actual effect is reduced. It is generally believed that when the fuel cell stack is at below freezing temperature, the liquid water remaining in the gas diffusion layer freezes, expands in volume, and melts again as the temperature rises, so that the gap space becomes larger and larger after the above-mentioned steps.

The microporous layer of the gas diffusion layer has a lotus leaf texture structure or a hydrophobic agent distribution structure of a leaf texture structure, wherein the lotus leaf texture structure, as shown in fig. 2A, includes a texture area and a residual area 110, i.e., a blank area which is not covered by the texture structure and is transverse to the texture area, i.e., adjacent to the texture area in the horizontal direction. A central loop contact channel 101 in which the textured region has a first width, a main contact channel 102 having a second, smaller width radiating from the center of the central loop contact channel 101, and a hydrophobizing agent distribution structure extending outwardly from the main contact channel having a sub-contact channel 103 having a third, smaller width. As shown in fig. 2C, the leaf texture region and the remainder region 210, the texture region 200 has a main contact channel 201 of a first width, the main contact channel is branched, a sub-contact channel 202 of a second smaller width extends outward from the main contact channel, and a sub-contact channel 203 of a third smaller width extends outward from the sub-contact channel.

In the preparation process, a screen plate with a lotus leaf texture structure or a leaf texture structure is designed and used, and the screen plate is prepared through a multiple screen printing process. The continuous primary and secondary coarse and fine distribution pattern is specially designed and prepared by the distribution difference of the hydrophobic agent, and the relative content of the hydrophobic agent in the lotus leaf texture structure or leaf texture structure of the microporous layer is higher or lower than that in the residual area of the microporous layer. The design has a bionic principle and primary and secondary difference, and can effectively improve the water-heat balance capability of the membrane electrode of the fuel cell. When the operation condition of the fuel cell is partially dry or one side of the cathode and the anode is partially dry, the relative content of the water repellent agent in the texture area of the lotus leaf texture structure or the leaf texture structure of the microporous layer is designed to be higher than that in the residual area of the microporous layer, so that large-area water tends to stay on the surface of the catalyst layer more, the proton exchange membrane is kept wet, the proton conduction efficiency is improved, and meanwhile, when reaction medium hydrogen or oxygen is conveyed in a flow field flow channel and is longitudinally diffused to the surface of the electrode, the water repellent agent can be orderly and directionally conveyed through the texture structures in the microporous layer. When the operation condition of the fuel cell is wet or one side of the cathode and the anode is wet, the relative content of the water repellent agent in the texture area of the lotus leaf texture structure or the leaf texture structure of the microporous layer is designed to be lower than that of the rest part of the microporous layer, so that large-area water tends to pass through the texture structures and is orderly and directionally conveyed out, and flooding and mass transfer polarization generation are avoided. The differential hydrophobic structure can effectively increase the mass transfer capacity of the gas diffusion layer and maintain the water-heat balance of the fuel cell.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1, fig. 1 is a schematic flow chart of a preparation method provided by an embodiment of the present invention, and the preparation method includes:

step S11: and (3) placing the gas diffusion layer substrate layer (3-1 or 4-1) in a water repellent agent solution to be soaked for one time or more, then placing the soaked gas diffusion layer substrate layer in an oven to be heated, and finally curing the soaked gas diffusion layer substrate layer in a high-temperature oven at 340-380 ℃.

Step S12: the gas diffusion layer substrate layer (3-1 or 4-1) processed in the step S11 is screen-printed with a screen having a lotus leaf texture or a leaf texture pattern, as shown in fig. 1A, i.e., a texture area, using a paste having a first hydrophobizing agent content, and after completion, is placed in an oven to be sufficiently dried. This step can be repeated 1-10 times to improve the effect.

Step S13: the gas diffusion layer substrate layer (3-1 or 4-1) processed in the step of S12 is screen-printed with a screen residual pattern screen (like a screen pattern in fig. 1B) having a pattern of lotus leaf texture or leaf texture in the step of S12, i.e., a residual area, using a paste having a second content of the hydrophobic agent, wherein the first content of the hydrophobic agent can be higher or lower than the second content of the hydrophobic agent, and after finishing, the substrate layer is placed in an oven to be fully dried.

Step S14: and (3) placing the treated gas diffusion layer in an oven at the temperature of 340-389 ℃ for heating, and fully volatilizing residual pore-forming agent, dispersing agent and solution.

It should be appreciated that in the above steps S12 and S13, the textured area or the remaining area may be screen-overprinted with a plurality of patterns. For example, in step S12, the texture region may be silk-screened in steps using a plurality of screens, for example, a central ring contact channel, a main contact channel, a sub-contact channel, etc. are respectively printed by different screens; also for example, in step S13, the remaining area may be silk-screened in steps using a plurality of screens, which has the advantage of reducing the difficulty of making a single screen mold. In addition, it is possible to separately prepare a first screen including only the center loop contact channel, the main contact channel, the sub-contact channel, and a second screen including two of them, and a third screen including three or more of them, and screen-print them by the first screen, the second screen, and the third screen in steps, which can still form a distinct difference in hydrophobic property in the formed textured area.

Based on the above embodiment, another embodiment of the present invention further provides a membrane electrode assembly, which is shown in fig. 4, where fig. 4 is a description of each component of a fuel cell membrane electrode assembled by gas diffusion layers prepared according to the present invention: 1 is a proton exchange membrane, reference numeral 2-1 is an anode catalyst layer, reference numeral 3-1 is an anode gas diffusion layer microporous layer, reference numeral 4-1 is an anode gas diffusion layer substrate part, reference numeral 2-2 is a cathode catalyst layer, reference numeral 3-2 is a cathode gas diffusion layer microporous layer, and reference numeral 4-2 is a cathode gas diffusion layer substrate part.

Based on the above embodiments, another embodiment of the present invention also provides a fuel cell including the membrane electrode assembly according to the above embodiments.

The performance of the fuel cell (examples one and two) using the microporous layer structure according to the present invention will be described in comparison with the performance of the fuel cell (example three) prepared by the conventional technology, with reference to specific design parameters.

The first embodiment is as follows: the gas diffusion layer with a lotus leaf-shaped or trefoil-shaped structure prepared by the technical scheme of the embodiment of the invention comprises the following components in parts by weight:

1) placing Toray H060 carbon paper in 20% of PTFE emulsion to be completely soaked, taking out the paper, naturally draining the emulsion for 20 seconds, supporting four corners of the carbon paper, suspending the paper in a high-temperature oven at 160 ℃ and drying the paper for 20 minutes; finally, drying in an oven at 340 ℃ for 50 minutes to form the carbon paper subjected to hydrophobic treatment; if a plurality of carbon papers are processed in one batch, all batches of carbon papers are processed and then dried in an oven at 340 ℃ for 50 minutes.

2) Weighing 3.2g Vulcan XC-72(R), 60ml of aqueous solution containing 2.5g of ammonium oxalate and 8g of 20 percent PTFE diluent, pouring into a certain amount of isopropanol, and uniformly stirring to prepare slurry with the viscosity of 300cp as microporous layer slurry; screen printing the slurry on one side of the above hydrophobic treated carbon paper using the screen of fig. 1A, and then placing in an oven at 160 ℃ to dry sufficiently; this step was repeated 2 times.

3) Weighing 3.2g Vulcan XC-72(R), 60ml of aqueous solution containing 2.5g of ammonium oxalate and 4g of 20 percent PTFE diluent, pouring into a certain amount of isopropanol, and uniformly stirring to prepare slurry with the viscosity of 300cp as microporous layer slurry; screen printing the slurry on the hydrophobic carbon paper side subjected to the screen printing in the previous step by using the screen plate in FIG. 1B, and then placing the hydrophobic carbon paper in an oven at 160 ℃ for full drying; this step was repeated 2 times.

4) And (3) putting the gas diffusion layer coated with the slurry into a muffle furnace, heating at a heating rate of 5 ℃/min, finally roasting at 340 ℃ for 60min, and taking the gas diffusion layer after the furnace temperature is reduced to room temperature to finish the preparation of the microporous layer.

Example two: the gas diffusion layer with a lotus leaf-shaped or trefoil-shaped structure prepared by the technical scheme of the embodiment of the invention comprises the following components in parts by weight:

2) Weighing 3.2g Vulcan XC-72(R), 60ml of aqueous solution containing 2.5g of ammonium oxalate and 4g of 20 percent PTFE diluent, pouring into a certain amount of isopropanol, and uniformly stirring to prepare slurry with the viscosity of 300cp as microporous layer slurry; screen printing the slurry on one side of the above hydrophobic treated carbon paper using the screen of fig. 1A, and then placing in an oven at 160 ℃ to dry sufficiently; this step was repeated 2 times.

3) Weighing 3.2g Vulcan XC-72(R), 60ml of aqueous solution containing 2.5g of ammonium oxalate and 8g of 20 percent PTFE diluent, pouring into a certain amount of isopropanol, and uniformly stirring to prepare slurry with the viscosity of 300cp as microporous layer slurry; screen printing the slurry on the hydrophobic carbon paper side subjected to the screen printing in the previous step by using the screen plate in FIG. 1B, and then placing the hydrophobic carbon paper in an oven at 160 ℃ for full drying; this step was repeated 2 times.

(2) Example three: gas diffusion layer prepared by traditional technical scheme

2) Weighing 3.2g Vulcan XC-72(R), 60ml of aqueous solution containing 2.5g of ammonium oxalate and 8g of 20 percent PTFE diluent, pouring into a certain amount of isopropanol, and uniformly stirring to prepare slurry with the viscosity of 300cp as microporous layer slurry; screen printing the slurry on one side of the above hydrophobic treated carbon paper using the screen of fig. 1A, and then placing in an oven at 160 ℃ to dry sufficiently; this step was repeated 4 times.

3) And (3) putting the gas diffusion layer coated with the slurry into a muffle furnace, heating at a heating rate of 5 ℃/min, finally roasting at 340 ℃ for 60min, and taking the gas diffusion layer after the furnace temperature is reduced to room temperature to finish the preparation of the microporous layer.

The two samples were assembled to have an active area of 200cm²The assembly mode of the gas diffusion layer prepared by the sample I and the flowing directions of cathode and anode gases are the same as those shown in the attached figure 3, and the electrochemical performance of the cell obtained by comparison is detected. The detection environment for the data of fig. 4 is: the cathode inlet pressure was the same as the anode inlet pressure, the anode inlet gas humidity was 50%, the cathode inlet gas humidity was 50%, and the other operating conditions were the same. The results showed that the concentration was 1.0A/cm²Above the electric density, the voltage of the battery prepared by the sample I still keeps stable, while the voltage of the battery prepared by the sample II is obviously reduced, and the phenomenon of mass transfer polarization occurs. In fig. 4, the horizontal axis represents current density, and the vertical axis represents voltage. Therefore, the fuel cell prepared by the technical scheme of the application has better self-humidifying effect and better cell performance.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention specifically discloses the following examples:

1. a gas diffusion layer, wherein a microporous layer of the gas diffusion layer has at least one textured area and at least one remainder area adjacent to the textured area, the textured area having a different hydrophobic agent content than the remainder area.

2. The gas diffusion layer of example 1, wherein the textured area is formed by at least two-stage channels having different widths.

3. A gas diffusion layer according to example 1, characterized in that: the remaining area is enclosed by the textured area.

4. The gas diffusion layer of example 1, wherein the textured area comprises a lotus leaf texture comprising a central ring-contacting channel having a first width, a primary channel of a second width radiating from the central ring channel, and a sub-channel extending outward from the primary channel having a third width, the first width being greater than the second width and greater than the third width, such that the central ring channel, the primary channel, and the sub-channel have different hydrophobicity.

5. The gas diffusion layer of example 1, wherein the textured area comprises a leaf texture having a main channel with dendrites of a first width, and sub-channels extending outward from the main channel with a second width, and sub-channels extending outward from the sub-channels with the second width, and a sub-channel with a third width, wherein the first width is greater than the second width and greater than the third width, such that the main channel, the sub-channels, and the sub-channels have different hydrophobicity.

6. The gas diffusion layer according to example 1, characterized in that: the hydrophobic agent is one or a mixture of at least two of polytetrafluoroethylene, a copolymer of tetrafluoroethylene and hexafluoropropylene, polyvinylidene fluoride or polychlorotrifluoroethylene. Preferably polytetrafluoroethylene.

7. The gas diffusion layer according to any one of examples 1 to 6, wherein the hydrophobic agent accounts for 1% to 40% of the total weight of the entire gas diffusion layer.

8. The gas diffusion layer according to any one of examples 1 to 7, wherein the hydrophobic agent accounts for 15 to 40% of the total weight of the gas diffusion layer as a whole

9. The gas diffusion layer according to example 1, wherein the microporous layer of the gas diffusion layer further comprises a dispersant, a conductive aid, a pore-forming agent, and the like.

10. The gas diffusion layer of example 9, wherein the dispersant includes, but is not limited to, sodium carboxymethylcellulose, methylcellulose, hydroxypropyl methylcellulose, polyethylene glycol monomethyl ether, hydroxyethyl cellulose, sodium alginate, carrageenan.

11. The gas diffusion layer of example 9, wherein the conductive additive comprises, but is not limited to, carbon Black, acetylene Black, ketjen Black, SUPER P, carbon nanotube powder, graphene, Vulcan XC-72, Black pearls.

12. The gas diffusion layer of example 9, wherein the pore-directing agent includes, but is not limited to, one or both of ammonium carbonate, ammonium oxalate, and lithium carbonate.

13. A method of preparing a gas diffusion layer according to any one of examples 1 to 12, comprising:

step S11: soaking the gas diffusion layer substrate layer in a hydrophobic agent solution for one or more times, then placing the soaked gas diffusion layer substrate layer in a drying oven for heating, and finally curing the gas diffusion layer substrate layer in a high-temperature drying oven at 340-380 ℃;

step S12: screen printing the gas diffusion layer substrate layer processed in the step S11 by using a screen plate with a lotus leaf texture structure or leaf texture structure pattern by using slurry with a first hydrophobic agent content, and then placing the screen plate in an oven for fully drying;

step S13: screen printing the gas diffusion layer substrate processed in the step S12 by using a screen residual pattern screen plate which has the pattern of the lotus leaf texture structure or the leaf texture structure used in the step S12 and by using slurry with a second hydrophobic agent content, and then fully drying the screen residual pattern screen plate in an oven;

step S14: and (4) placing the gas diffusion layer processed in the step (S13) in an oven at the temperature of 340-389 ℃ for heating, and fully volatilizing residual pore-forming agent, dispersing agent and solution.

14. The method according to example 13, wherein the hydrophobic agent is one or more selected from polytetrafluoroethylene, a copolymer of tetrafluoroethylene and hexafluoropropylene, polyvinylidene fluoride, and polychlorotrifluoroethylene, and preferably polytetrafluoroethylene.

15. The method according to example 13, wherein the total content of the water repellent agent is 1 to 40%, preferably 15 to 40%, based on the total weight of the microporous layer of the gas diffusion layer as a whole.

16. The method of manufacturing a gas diffusion layer according to example 13, wherein the microporous layer of the gas diffusion layer further comprises a dispersant, a conductive aid, and a pore-forming agent.

17. The method of manufacturing of example 15, wherein the dispersing agent comprises, but is not limited to, sodium carboxymethylcellulose, methylcellulose, hydroxypropyl methylcellulose, polyethylene glycol monomethyl ether, hydroxyethyl cellulose, sodium alginate, carrageenan.

18. The method of making according to example 15, wherein the conductive aid comprises, but is not limited to, carbon Black, acetylene Black, ketjen Black, SUPER P, carbon nanotube powder, graphene, Vulcan XC-72, Black pearls.

19. The method of preparing according to example 15, wherein the pore-directing agent includes, but is not limited to, one or both of ammonium carbonate, ammonium oxalate, and lithium carbonate.

20. The method of making according to example 13, wherein the first hydrophobizing agent content is greater than the second hydrophobizing agent content.

21. The method of making according to example 13, wherein the first hydrophobizing agent content is less than the second hydrophobizing agent content.

22. The method of manufacturing of example 13, wherein the textured area or the residual area is screen-overprinted with a plurality of screens in the above step S12 and/or step S13.

23, the production method according to example 13, wherein in step S12, a first screen plate including only the center loop contact channel, the main contact channel, and the sub-contact channel, a second screen plate including two of them, and a third screen plate including three or more of them are prepared, respectively, and screen printing is performed by the first screen plate, the second screen plate, and the third screen plate in steps to form a remarkably different difference in hydrophobic property in the formed textured area.

24. A membrane electrode assembly, comprising:

a cathode-side gas diffusion layer, a cathode-side catalyst layer, a proton exchange membrane, an anode-side catalyst layer, and an anode-side gas diffusion layer which are stacked in this order;

wherein the cathode-side gas diffusion layer is prepared including the microporous layer structure gas diffusion layer according to any one of examples 1 to 12; the anode-side gas diffusion layer was prepared by using a gas diffusion layer having a microporous layer structure according to any one of examples 1 to 12

25. A fuel cell, characterized in that the fuel cell comprises:

a fuel cell stack comprised of a membrane electrode assembly, a polar plate, a current collector plate, an insulator plate, a seal structure, an end plate, etc., as described in example 24.

Claims

2. A production process for producing the gas diffusion layer according to claim 1,

the method is characterized by comprising the following steps:

3. A membrane electrode assembly, comprising:

wherein the cathode-side gas diffusion layer is prepared including the microporous layer structure gas diffusion layer according to claim 1; the anode-side gas diffusion layer is prepared by including the microporous layer structure gas diffusion layer according to claim 1.

4. A fuel cell, characterized in that the fuel cell comprises:

a fuel cell stack comprising a membrane electrode assembly, a polar plate, a current collector, an insulator plate, a seal structure, an end plate, etc., according to claim 3.