A gas diffusion layer, a method for preparing the same, and a fuel cell

Abstract

The present invention discloses a gas diffusion layer, a preparation method thereof, and a fuel cell. Among them, a gas diffusion layer includes a first microporous layer, a second microporous layer, and a carbon fiber base layer. The first microporous layer is laminated between the second microporous layer and the carbon fiber base layer. The first microporous layer is made of a hydrophobic material and a first conductive carbon material, and the second microporous layer is made of a hydrophilic material and a second conductive carbon material. Both the first microporous layer and the second microporous layer are porous structures. The second microporous layer has a hydrophilic material, and the hydrophilic functional groups in the hydrophilic material and the polar structure similar to water molecules can retain water molecules, and can effectively lock the water molecules in the gas under low humidity conditions to achieve the effect of self-humidification. The first microporous layer has a hydrophobic material, which can exclude excess moisture and prevent excessive moisture from blocking the pores of the first microporous layer and the second microporous layer, affecting mass transfer and reducing the performance of the membrane electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of battery technologies, and particularly relates to a gas diffusion layer, a preparation method thereof, and a fuel cell. Background Art

[0002] Compared with traditional technologies, proton exchange membrane fuel cells have the advantages of high energy conversion efficiency, high power density, environmental friendliness, low operating temperature, low corrosiveness, quiet operation, etc., and are expected to become one of the most promising new energy technologies. However, in order to maintain sufficient hydration of the proton exchange membrane, hydrogen and air are usually introduced outside the battery through a humidifying device before entering the battery, and at the same time, heating equipment is required to heat and control the temperature of the gas and the battery. These additional humidifying devices and heating equipment make the system more complex, increase the cost, and the humidifying device and heating equipment also increase the space and weight of the proton exchange membrane fuel cell itself, which is not conducive to carrying. Therefore, researching a gas diffusion layer that can self-humidify has become a technical problem that needs to be solved urgently. Summary of the Invention

[0003] Based on this, it is necessary to provide a gas diffusion layer that can self-humidify to solve the technical problem in the prior art that a humidifying device and heating equipment need to be set to maintain sufficient hydration of the proton exchange membrane, resulting in an increase in the cost of the membrane fuel cell.

[0004] A gas diffusion layer provided by the present invention includes a first microporous layer, a second microporous layer, and a carbon fiber base layer. The first microporous layer is laminated between the second microporous layer and the carbon fiber base layer. The first microporous layer is made of a hydrophobic material and a first conductive carbon material, the second microporous layer is made of a hydrophilic material and a second conductive carbon material, and both the first microporous layer and the second microporous layer are porous structures.

[0005] Further, the carbon fiber length of the carbon fiber base layer is 5 to 40 millimeters.

[0006] Further, the carbon fiber base layer includes one of carbon paper, carbon felt, and carbon cloth.

[0007] Further, the hydrophobic material is a fluororesin.

[0008] Further, the thickness of the first microporous layer is 5 to 30 micrometers.

[0009] Further, the thickness of the second microporous layer is 1 to 20 micrometers.

[0010] Further, the thickness ratio of the first microporous layer to the second microporous layer is 1:0.2 to 1:1.

[0011] Further, the particle sizes of the first conductive carbon material and the second conductive carbon material are both 5 to 200 nanometers.

[0012] The present invention also provides a method for preparing the above gas diffusion layer, comprising the following steps:

[0013] Prepare a first intermediate by configuring a first conductive carbon material, a hydrophobic material, a thickening agent, and water in a preset ratio;

[0014] Coat the first intermediate on a carbon fiber base layer and dry to form a first microporous layer;

[0015] Prepare a second intermediate by configuring a second conductive carbon material, a precursor material of a hydrophilic material, and water in a preset ratio;

[0016] Coat the second intermediate on the first microporous layer and dry to form a second microporous layer;

[0017] Perform heat treatment on the carbon fiber base layer, the first microporous layer, and the second microporous layer to obtain a gas diffusion layer.

[0018] Specifically, the step of configuring the second intermediate includes:

[0019] Take 0.1 to 1 part by mass of silicate, 5 to 10 parts by mass of carbon material, 1 to 2 parts by mass of thickening agent, and 50 to 100 parts by mass of water, mix them, and stir in a water bath at 10 to 30 °C at 1000 to 3000 rpm for 90 to 150 min to form a first slurry;

[0020] Add an acid solution with a pH value of 2 to 5 to the first slurry until the pH is 4 to 6, and then stir at a speed of 1000 to 3000 rpm at a temperature of 40 to 60 °C for 10 to 30 min to form a second slurry;

[0021] Add 0.001 to 0.005 part by mass of a silane coupling agent to the second slurry, and then stir at 1000 to 3000 rpm for 5 to 15 min to form a second intermediate slurry;

[0022] Among them, the silicate is one of lithium silicate, sodium silicate, potassium silicate, and magnesium silicate;

[0023] The thickening agent is one of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid;

[0024] The acid solution is one of formic acid, acetic acid, hydrochloric acid, and sulfuric acid;

[0025] The coupling agent is one of methoxysilane coupling agent and ethoxysilane coupling agent;

[0026] The heat treatment conditions are as follows: from room temperature, it is heated to 160 - 200°C at a rate of 1 - 5°C / min, held for 5 - 30 min, then heated to 320 - 360°C at a rate of 1 - 5°C / min, and held for 5 - 20 min.

[0027] A fuel cell provided by the present invention includes the above-mentioned gas diffusion layer.

[0028] A gas diffusion layer provided by the present invention is prepared by mixing a silica precursor into a slurry, and through heat treatment, the precursor is decomposed to prepare a hydrophilic material silica, effectively reducing the loss of hydrophilic functional groups on the surface of silica during the heat treatment process. The hydrophilic functional groups and the polar structure similar to water molecules can retain water molecules, and can effectively lock the water molecules in the gas under low humidity conditions to achieve the effect of self-humidification. At the same time, during the heat treatment process, the decomposition of the precursor and the decomposition of the thickener in the slurry further improve the pore structure of the diffusion layer, thereby enhancing the water-vapor management ability of the gas diffusion layer. The first microporous layer is laminated between the second microporous layer and the carbon fiber base layer. The first microporous layer has a hydrophobic material, which can exclude excess water and prevent the pores of the first microporous layer and the second microporous layer from being blocked by too much water, affecting mass transfer and reducing the performance of the membrane electrode. After the second microporous layer locks part of the water, it is beneficial to improve the operating performance of the membrane electrode under low humidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0030] Figure 1 It is a schematic structural diagram of a gas diffusion layer in an embodiment of the present invention;

[0031] Figure 2 It is a battery performance curve graph measured for the gas diffusion layer prepared in Example 1 of the present invention;

[0032] Figure 3 It is a battery performance curve graph measured for the gas diffusion layer prepared without the second microporous layer in Example 1 of the present invention.

[0033] MAIN COMPONENTS:

[0034] 100. Carbon fiber base layer; 200. First microporous layer; 300. Second microporous layer.

[0035] The realization, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. Detailed implementation manners

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that all the directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0038] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, "and / or" throughout the text includes three solutions. Taking A and / or B as an example, it includes the technical solution of A, the technical solution of B, and the technical solution that A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0039] As Figure 1 shown, in some embodiments, a gas diffusion layer includes a first microporous layer 200, a second microporous layer 300, and a carbon fiber base layer 100. The first microporous layer 200 is stacked between the second microporous layer 300 and the carbon fiber base layer 100. The first microporous layer 200 is made of a hydrophobic material and a first conductive carbon material, the second microporous layer 300 is made of a hydrophilic material and a second conductive carbon material, and both the first microporous layer 200 and the second microporous layer 300 are porous structures.

[0040] During operation, the second microporous layer 300 has a hydrophilic material. The hydrophilic functional groups in the hydrophilic material and the polar structure similar to water molecules can retain water molecules, effectively locking the water molecules in the gas under low humidity conditions to achieve the effect of self-humidification. The first microporous layer 200 is stacked between the second microporous layer 300 and the carbon fiber base layer 100. The first microporous layer 200 has a hydrophobic material, which can exclude excess moisture, prevent excessive moisture from blocking the pores of the first microporous layer 200 and the second microporous layer 300 and affecting mass transfer, and reduce the performance of the membrane electrode. After the second microporous layer 300 locks part of the moisture, it is beneficial to improve the operating performance of the membrane electrode under low humidity.

[0041] Specifically, the first conductive carbon material and the second conductive carbon material can be, but are not limited to, conductive carbon black.

[0042] Furthermore, the carbon fiber base layer 100 includes one of carbon paper, carbon felt, and carbon cloth. The carbon fiber length of the carbon paper and the carbon felt is 5 to 40 mm. Preferably, the carbon fiber length of the carbon paper and the carbon felt is 6 to 20 mm. The carbon cloth is prepared by continuous carbon fibers and by weaving or knitting.

[0043] If the areal density of the material of the carbon fiber base layer 100 is less than or equal to 15 g / m 2 , then the areal density tolerance of each region of the material is less than or equal to 15%. If the areal density of the base layer material is greater than 15 g / m 2 , then the areal density tolerance of each region of the material is less than or equal to 10%.

[0044] In some embodiments, the hydrophobic material is a fluororesin. Specifically, by weight, the content of the fluororesin in the first microporous layer 200 is 5% to 40%. More specifically, the hydrophobic material is polytetrafluoroethylene.

[0045] Even further, the thickness of the first microporous layer 200 is 5 to 30 μm. The thickness of the second microporous layer 300 is 1 to 20 μm. The thickness ratio of the first microporous layer 200 to the second microporous layer 300 is 1:0.2 to 1:1. The sum of the thicknesses of the first microporous layer 200 and the second microporous layer 300 is 5 to 40 μm.

[0046] In another embodiment, a method for preparing a gas diffusion layer includes the following steps:

[0047] S1: Configure a first intermediate by mixing a first conductive carbon material, a hydrophobic material, a thickener, and water in a preset ratio;

[0048] S2: Coat the first intermediate on the carbon fiber base layer and form a first microporous layer after drying;

[0049] S3: Configure a second intermediate by mixing a second conductive carbon material, a precursor material of a hydrophilic material, and water in a preset ratio;

[0050] S4: Coat the second intermediate on the first microporous layer and form the second microporous layer after drying;

[0051] S5: Heat-treat the carbon fiber base layer, the first microporous layer and the second microporous layer to obtain the gas diffusion layer.

[0052] Specifically, the steps of configuring the second intermediate include:

[0053] Take 0.1 - 1 part by mass of silicate, 5 - 10 parts by mass of carbon material, 1 - 2 parts by mass of thickener, and 50 - 100 parts by mass of water, mix them and stir at 1000 - 3000 rpm in a water bath at 10 - 30 °C for 90 - 150 min to form Slurry 1;

[0054] Add an acid solution with a pH value of 2 - 5 to Slurry 1 until the pH is 4 - 6, and then stir at a speed of 1000 - 3000 rpm at a temperature of 40 - 60 °C for 10 - 30 min to form Slurry 2;

[0055] Add 0.001 - 0.005 part by mass of silane coupling agent to Slurry 2, and then stir at 1000 - 3000 rpm for 5 - 15 min to form the second intermediate slurry;

[0056] Among them, the silicate is one of lithium silicate, sodium silicate, potassium silicate, and magnesium silicate. For the addition form of the silicate, if it is a solution, it shall be calculated based on the mass of the silicate in the solution. If the addition form is a solid, its particle size shall be 0.5 - 5 μm to ensure sufficient dispersion in the slurry;

[0057] The thickener is one of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid;

[0058] The acid solution is one of formic acid, acetic acid, hydrochloric acid, and sulfuric acid;

[0059] The coupling agent is one of methoxysilane coupling agent and ethoxysilane coupling agent to achieve the effect of enhancing the bonding performance of the hydrophilic and hydrophobic layers;

[0060] The heat treatment conditions are as follows: raise the temperature from room temperature to 160 - 200 °C at a rate of 1 - 5 °C / min, hold for 5 - 30 min, and then raise the temperature to 320 - 360 °C at a rate of 1 - 5 °C / min and hold for 5 - 20 min.

[0061] In another embodiment, a fuel cell includes a gas diffusion layer.

[0062] To better explain the present invention, the following specific embodiments are provided.

[0063] Example 1

[0064] A preparation method of a gas diffusion layer, wherein the carbon fiber base layer is carbon paper, and the fiber length of the carbon paper is between 6 and 15 mm, and the areal density parameter is 15 ± 2 g / m 2 Among them, the first intermediate with hydrophobic properties is prepared from conductive carbon black, polytetrafluoroethylene, polyvinyl alcohol 2488, and water in a mass ratio of 1:0.25:0.2:10. Among them, the particle size of the conductive carbon black is 8-20 nanometers. The first intermediate is coated on the carbon paper, and after drying, the first microporous layer is formed.

[0065] Prepare the second intermediate:

[0066] Take 0.5 parts by mass of sodium silicate with a particle size of 0.5 microns, 10 parts by mass of conductive carbon black, 1 part by mass of polyethylene glycol 600, and 85 parts by mass of water, mix them, and stir at 1500 rpm in a 20°C water bath for 150 min to form slurry one;

[0067] Add a hydrochloric acid solution with a pH value of 3 to slurry one until the pH is 5, and then stir at a speed of 1500 rpm at a temperature of 50°C for 20 min to form slurry two;

[0068] Add 0.003 parts by mass of 3-glycidoxypropyltrimethoxysilane coupling agent to slurry two, and then stir at 1500 rpm for 15 min to form the second intermediate slurry.

[0069] The second intermediate is coated on the first microporous layer, and after drying, the second microporous layer is formed. The thickness of the first microporous layer is 20 microns, and the thickness of the second microporous layer is 10 microns. The dried carbon paper is heat-treated in a muffle furnace, heated from room temperature to 180°C at a rate of 5°C / min, held for 20 min, and then heated to 360°C at a rate of 5°C / min and held for 10 min to obtain the gas diffusion layer.

[0070] As Figure 2 and Figure 3 shown in the curve graph of, the battery performance measured for the gas diffusion layer provided with the second microporous layer is better than that of the gas diffusion layer without the second microporous layer.

[0071] Example 2

[0072] A preparation method of a gas diffusion layer, wherein the carbon fiber base layer is carbon paper, and the fiber length of the carbon paper is between 6 and 15 mm, and the areal density parameter is 20 ± 2 g / m 2Among them, the first intermediate with hydrophobic properties is prepared from conductive carbon black, polytetrafluoroethylene, polyvinyl alcohol 2488, and water in a mass ratio of 1:0.25:0.2:10. Among them, the particle size of the conductive carbon black is 8-20 nanometers. The first intermediate is coated on the carbon paper, and after drying, the first microporous layer is formed.

[0073] Prepare the second intermediate:

[0074] Take 0.2 parts by mass of sodium silicate with a particle size of 2 microns, 8 parts by mass of conductive carbon black, 0.8 parts by mass of polyvinyl alcohol 2488, and 80 parts by mass of water, mix them, and stir in a 20°C water bath at 1500 rpm for 150 min to form Slurry 1;

[0075] Add a hydrochloric acid solution with a pH of 3 to Slurry 1 until the pH is 5, and then stir at a speed of 1500 rpm at a temperature of 50°C for 20 min to form Slurry 2;

[0076] Add 0.004 parts by mass of 3-glycidoxypropyltrimethoxysilane coupling agent to Slurry 2, and then stir at 1500 rpm for 15 min to form the second intermediate slurry.

[0077] Coat the second intermediate on the first microporous layer. After drying, the second microporous layer is formed. The thickness of the first microporous layer is 20 microns, and the thickness of the second microporous layer is 5 microns. The dried carbon paper is heat-treated in a muffle furnace, heated from room temperature to 180°C at a rate of 5°C / min, held for 20 min, and then heated to 350°C at a rate of 5°C / min and held for 10 min to obtain the gas diffusion layer.

[0078] Example 3

[0079] A method for preparing a gas diffusion layer, the carbon fiber base layer is carbon paper, and the fiber length of the carbon paper used is between 15-25 mm, and the areal density parameter is 20±2 g / m 2 Among them, the first intermediate with hydrophobic properties is prepared from conductive carbon black, polytetrafluoroethylene, polyvinyl alcohol 2488, and water in a mass ratio of 1:0.3::0.2:10. Among them, the particle size of the conductive carbon black is 5-10 nanometers. The first intermediate is coated on the carbon paper, and after drying, the first microporous layer is formed.

[0080] Prepare the second intermediate:

[0081] Take 10 parts by mass of a potassium silicate solution with a concentration of 10%, 9 parts by mass of conductive carbon black, 1 part by mass of polyvinyl alcohol 2488, and 85 parts by mass of water, mix them, and stir in a 20°C water bath at 1500 rpm for 150 min to form Slurry 1;

[0082] Add hydrochloric acid solution with a pH of 4 to Slurry 1 until the pH reaches 6, and then stir at a speed of 1500 rpm at a temperature of 50 °C for 20 min to form Slurry 2;

[0083] Add 0.005 parts by mass of 3-glycidoxypropyltrimethylsilane coupling agent to Slurry 2, and then stir at 1500 rpm for 15 min to form the second intermediate slurry.

[0084] Coat the second intermediate on the first microporous layer, and the second microporous layer is formed after the second intermediate is dried. The thickness of the first microporous layer is 15 μm, and the thickness of the second microporous layer is 5 μm. The dried carbon paper is heat-treated in a muffle furnace, heated from room temperature to 180 °C at a rate of 5 °C / min, held for 20 min, and then heated to 350 °C at a rate of 5 °C / min and held for 10 min to obtain the gas diffusion layer.

[0085] Example 4

[0086] A method for preparing a gas diffusion layer, the carbon fiber base layer is carbon paper, and the fiber length of the carbon paper used is between 15 and 25 mm, and the areal density parameter is 15 ± 2 g / m 2 . The first intermediate with hydrophobic properties is prepared from conductive carbon black, polytetrafluoroethylene, polyacrylic acid, and water in a mass ratio of 1:0.4:0.3:10. Among them, the particle size of the conductive carbon black is 5 to 10 nanometers. Coat the first intermediate on the carbon paper, and the first microporous layer is formed after the first intermediate is dried.

[0087] Prepare the second intermediate:

[0088] Take 5 parts by mass of potassium silicate solution with a concentration of 10%, 10 parts by mass of conductive carbon black, 1 part by mass of polyethylene glycol 2000, and 90 parts by mass of water, mix them, and stir at 1500 rpm in a 20 °C water bath for 150 min to form Slurry 1;

[0089] Add hydrochloric acid solution with a pH of 4 to Slurry 1 until the pH reaches 6, and then stir at a speed of 1500 rpm at a temperature of 50 °C for 20 min to form Slurry 2;

[0090] Add 0.005 parts by mass of 3-glycidoxypropyltrimethylsilane coupling agent to Slurry 2, and then stir at 1500 rpm for 15 min to form the second intermediate slurry.

[0091] The second intermediate is coated on the first microporous layer, and after drying, the second microporous layer is formed. The thickness of the first microporous layer is 20 microns, and the thickness of the second microporous layer is 10 microns. The dried carbon paper is heat-treated in a muffle furnace, heated from room temperature to 180 °C at a rate of 5 °C / min, held for 20 min, and then heated to 360 °C at a rate of 5 °C / min and held for 10 min to obtain the gas diffusion layer.

[0092] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A gas diffusion layer, characterized in that, It includes a first microporous layer, a second microporous layer and a carbon fiber base layer. The first microporous layer is laminated between the second microporous layer and the carbon fiber base layer. The first microporous layer is made of a hydrophobic material and a first conductive carbon material. The second microporous layer is made of a hydrophilic material and a second conductive carbon material. Both the first microporous layer and the second microporous layer are porous structures; Configure a first intermediate by mixing a first conductive carbon material, a hydrophobic material, a thickener and water in a preset ratio; Coat the first intermediate on the carbon fiber base layer and form the first microporous layer after drying; Configure a second intermediate by mixing a second conductive carbon material, a precursor material of a hydrophilic material and water in a preset ratio; Coat the second intermediate on the first microporous layer and form the second microporous layer after drying; Perform heat treatment on the carbon fiber base layer, the first microporous layer and the second microporous layer to obtain a gas diffusion layer; The step of configuring the second intermediate includes: Take 0.1 - 1 part by mass of silicate, 5 - 10 parts by mass of carbon material, 1 - 2 parts by mass of thickener, 50 - 100 parts by mass of water, mix them, and stir at 1000 - 3000 rpm in a water bath at 10 - 30 °C for 90 - 150 min to form a first slurry; Add an acid solution with a pH value of 2 - 5 to the first slurry until the pH is 4 - 6, and then stir at a speed of 1000 - 3000 rpm at a temperature of 40 - 60 °C for 10 - 30 min to form a second slurry; Add 0.001 - 0.005 part by mass of a silane coupling agent to the second slurry, and then stir at 1000 - 3000 rpm for 5 - 15 min to form a second intermediate slurry.

2. The gas diffusion layer according to claim 1, characterized in that, The carbon fiber base layer includes one of carbon paper, carbon felt and carbon cloth.

3. The gas diffusion layer according to claim 1, characterized in that, The hydrophobic material is a fluororesin.

4. The gas diffusion layer according to claim 1, wherein The thickness of the first microporous layer is 5 - 30 microns.

5. The gas diffusion layer according to claim 1, wherein The thickness of the second microporous layer is 1 - 20 microns.

6. The gas diffusion layer according to claim 1, wherein, The thickness ratio of the first microporous layer to the second microporous layer is 1:0.2 - 1:

1.

7. The gas diffusion layer according to claim 1, wherein The particle sizes of both the first conductive carbon material and the second conductive carbon material are 5 - 200 nanometers.

8. A method for preparing a gas diffusion layer according to any one of claims 1 to 7, characterized in that, It includes the following steps: Configure a first intermediate by mixing a first conductive carbon material, a hydrophobic material, a thickener and water in a preset ratio; Coat the first intermediate on the carbon fiber base layer and form the first microporous layer after drying; Configure a second intermediate by mixing a second conductive carbon material, a precursor material of a hydrophilic material and water in a preset ratio; Coat the second intermediate on the first microporous layer and form the second microporous layer after drying; Perform heat treatment on the carbon fiber base layer, the first microporous layer and the second microporous layer to obtain a gas diffusion layer.

9. The method for preparing the gas diffusion layer according to claim 8, wherein The step of configuring the second intermediate includes: Take 0.1 - 1 part by mass of silicate, 5 - 10 parts by mass of carbon material, 1 - 2 parts by mass of thickener, 50 - 100 parts by mass of water, mix them, and stir at 1000 - 3000 rpm in a water bath at 10 - 30 °C for 90 - 150 min to form a first slurry; Add an acid solution with a pH value of 2 - 5 to Slurry 1 until the pH reaches 4 - 6, and then stir at a speed of 1000 - 3000 rpm for 10 - 30 min at a temperature of 40 - 60 °C to form Slurry 2; Add 0.001 - 0.005 parts by mass of a silane coupling agent to Slurry 2, and then stir at 1000 - 3000 rpm for 5 - 15 min to form a second intermediate slurry; Among them, the silicate is one of lithium silicate, sodium silicate, potassium silicate, and magnesium silicate; The thickener is one of polyethylene glycol, polyvinyl alcohol, and polyacrylic acid; The acid solution is one of formic acid, acetic acid, hydrochloric acid, and sulfuric acid; The coupling agent is one of methoxysilane coupling agent and ethoxysilane coupling agent; The heat treatment conditions are as follows: raise the temperature from room temperature to 160 - 200 °C at a rate of 1 - 5 °C / min, hold for 5 - 30 min, and then raise the temperature to 320 - 360 °C at a rate of 1 - 5 °C / min, and hold for 5 - 20 min.

10. A fuel cell, characterized in that, It includes the gas diffusion layer according to any one of claims 1 to 7.

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