Fuel cell gas diffusion layer capable of realizing gas-liquid separation transmission and preparation method thereof

Abstract

The invention discloses a fuel cell gas diffusion layer capable of realizing gas-liquid separation transmission and a preparation method thereof, the gas diffusion layer comprises a main body, a plurality of through holes are vertically arranged on the main body according to a preset arrangement rule, and the through holes comprise large through holes and small through holes; the large through hole is an air inlet channel, and the small through hole is a drainage channel; the air inlet channel and the water drainage channel are arranged in a mutually separated mode. And by designing the pore size, water generated by reaction can be preferentially discharged in time through a water path, so that timely supply of fuel gas is guaranteed, separated transmission of gas and product water is ensured, and the durability and stability of the battery are improved.

Description

Technical Field

[0001] The invention relates to a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, belonging to the technical field of proton exchange membrane fuel cells. Background Art

[0002] As a low-temperature fuel cell, proton exchange membrane fuel cell (PEMFC) not only has high energy conversion efficiency and is green and environmentally friendly, but also has a relatively long lifespan. Therefore, it has become one of the most promising new energy devices to replace traditional energy devices. PEMFC mainly consists of four core components: bipolar plate, gas diffusion layer, catalyst layer and proton exchange membrane. Among them, the gas diffusion layer (GDL) plays the role of conducting electricity, conducting heat, supporting the catalyst layer and transmitting and draining gas. In addition to smoothly carrying the gas transmitted by the bipolar plate to the catalyst layer, the cathode GDL also needs to discharge the water generated by the reaction on one side of the cathode catalyst layer in time, so as to ensure the stable operation of the battery to provide electricity to the external load. Once the product water of the reaction cannot be discharged in time, it will block the pores of the GDL, affect the gas supply, and even cause flooding in severe cases, eventually forcing the battery to stop working. Therefore, as the main bearer of water management capabilities, the reasonable design of the gas diffusion layer plays an important role in ensuring the gas transmission efficiency and the smooth operation of the battery.

[0003] The Chinese invention patent with publication number CN114335571A discloses a gas diffusion layer, in which the cathode diffusion layer has a gradient design for the porosity and through-hole diameter of the material. The cathode diffusion layer is provided with a plurality of pore structures, and its porosity increases in a gradient along the flow direction of the fluid; at the same time, a plurality of through-holes are designed in the portion corresponding to the cathode flow channel position in the cathode diffusion layer, and the through-hole diameter increases in a gradient along the flow direction of the fluid. The gradient design of the gas diffusion layer makes the water management performance more superior, but it may be difficult to completely avoid the occurrence of flooding by relying solely on the porosity gradient of the material itself, and the through-hole diameter is only designed in a gradient in the plane direction, which has little effect on drainage in the vertical direction.

[0004] The Chinese invention patent with publication number CN113241448A discloses a gradient microporous gas diffusion layer for a proton exchange membrane fuel cell and a preparation method thereof. The gas diffusion layer utilizes the geometric feature differences between different carbon materials to construct a microporous layer with a gradient pore size structure, and further utilizes the concentration change of polytetrafluoroethylene to construct a gradient hydrophilic and hydrophobic structure, thereby obtaining a gradient microporous gas diffusion layer with an orderly hydrophilic and hydrophobic structure and a gradual pore distribution. The gradient pore size and gradient hydrophilic and hydrophobic structure of the gas diffusion layer can reduce the probability of flooding of the GDL, but the gradient pore size achieved by the material itself is prone to form blind holes, which limits the uniform distribution and effective discharge of water inside the diffusion layer.

[0005] GDL's research is dedicated to improving water management capabilities. Current research focuses on the gradient design of material porosity and hydrophobicity, and no differentiated design is performed on the channels for air intake and drainage. At high current density, water is generated faster and in greater quantities. When most of the pores are occupied by water, gas transmission is restricted, resulting in insufficient fuel supply, a reduced reaction rate, or even a shutdown of the reaction. Summary of the invention

[0006] The technical problem to be solved by the present invention is that the gas diffusion layer of the existing proton exchange membrane fuel cell is prone to water flooding, which hinders the gas supply.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: A fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission comprises a main body on which a plurality of through holes are vertically arranged according to a preset arrangement rule, wherein the through holes comprise large through holes and small through holes; the large through holes are air intake channels, and the small through holes are drainage channels; the air intake channels and the drainage channels are arranged separately from each other.

[0008] The aforementioned fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, wherein the air inlet channels are arranged in a row and column matrix, the cross section of the air inlet channels is square or circular, and the side length or diameter is 1000 nanometers to 1000 micrometers; Outside the space occupied by the air inlet channel, the drainage channels are arranged in a row and column matrix, and the cross-section of the drainage channels is square or circular, with a side length or diameter of 10-1000 nanometers.

[0009] The aforementioned fuel cell gas diffusion layer that can realize gas-liquid separation and transmission, the cross-sections of the air intake channel and the drainage channel are through holes with the same shape and size in the depth direction; or the cross-sections of the air intake channel and the drainage channel are gradient holes with the same shape in the depth direction but gradually decreasing size; or the cross-sections of the air intake channel and the drainage channel are tapered circular holes in the depth direction.

[0010] A method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission comprises the following steps: S1. preparing ink as a raw material for a gas diffusion layer; S2. Using an ink direct writing 3D printing method, a gas diffusion layer with a gas-liquid separation path is prepared; S3. Perform hydrophobic sintering and drying treatment on the printed samples.

[0011] The aforementioned method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission comprises the following steps in step S1: S11, weighing a set proportion of conductive carbon material, dispersant, binder, and thickener, and mixing them with deionized water in a set order to obtain a mixed solution; S12, subjecting the mixed solution to ultrasonic oscillation in an ultrasonic cleaner to disperse and fully mix the components in the mixed solution; S13, continue stirring with a magnetic stirrer to make the ink slurry after ultrasonic treatment more evenly dispersed; S14. Use a degassing stirring device to remove the bubbles remaining in the ink to obtain a raw material that can be directly used for ink direct writing 3D printing.

[0012] In the aforementioned method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission, in step S2, 3D printing comprises the following steps: S21, establishing a three-dimensional model according to the structure to be printed, and saving the three-dimensional model as an STL format file; S22, importing the STL format file into the slicing software for slicing processing, setting slicing parameters, and exporting the G-code format file; the slicing parameters include slicing fill rate, printing needle diameter, and printing layer height; S23, import the G-code format file into the printing software connected to the printer, adjust the extrusion pressure and printing speed, and start the printing process.

[0013] The aforementioned method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission is to evenly arrange large square through holes inside a three-dimensional model according to preset rules, wherein the large square through holes are air inlet channels, and the small through holes generated by slicing are drainage channels.

[0014] The aforementioned method for preparing a gas diffusion layer that can realize gas-liquid separation and transmission, after printing is completed, laser perforation is used to obtain nano-scale conical gradient holes according to the set arrangement rules. The large through holes generated by 3D printing are used as air inlet channels, and the small through holes generated by laser perforation are used as drainage channels.

[0015] The aforementioned method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission has a printing layer height of 2-5 layers; and the thickness of the gas diffusion layer is 200-600 microns.

[0016] The aforementioned method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission comprises the following steps in step S3: S31, preparing a hydrophobic agent solution with a set mass percentage; S32, using ultrasonic spraying equipment to control the diameter of particles during the spraying process so that the hydrophobic agent is evenly dispersed on the surface of the diffusion layer; S33, after the spraying is completed, the sample is placed in a vacuum drying oven for drying to preliminarily remove the residual moisture in the printed sample; S34. Under the set inert gas protection environment, place the sample in a tube furnace and control the heating process to melt the hydrophobic agent and bond it to the sample surface, while completely removing residual moisture.

[0017] Beneficial effects achieved by the present invention: A fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission of the present invention is structurally provided with pore passages of different sizes, wherein small pores are used for drainage and large pores are used for air intake. Since the small pores can more effectively attract water by capillary action, water generated by the reaction is preferentially directed to the drainage channel, thereby forming a gas-liquid separation transmission path to ensure timely removal of reaction product water and timely supply of fuel gas, thereby improving the stability of battery operation.

[0018] The present invention provides a method for preparing a fuel cell gas diffusion layer that can realize gas-liquid separation and transmission. The formed gas-liquid separation and transmission channel is orderly, the main part is manufactured using 3D printing technology, and the internal material transmission channel is formed by preset 3D printing holes or laser perforation. Therefore, the overall structure is orderly and the size of the hole can be precisely controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 (a) is a top view of the structure of a gas diffusion layer in Example 1 of the present invention; FIG1( b ) is a front view of the structure of the gas diffusion layer in Example 1 of the present invention; Figure 2 This is a schematic diagram of the straight through holes obtained by printing the gas diffusion layer in Example 1 of the present invention; FIG3 (a) is a schematic diagram of the main body structure and grid arrangement of the gas diffusion layer obtained by ink 3D printing under an optical microscope in Example 2 of the present invention; FIG3 (b) is a diagram showing the morphological characteristics of the material and the gradient effect of the material transmission channel after the ink 3D printing is completed in Example 2 of the present invention; Figure 4 This is a schematic diagram of the gradient through holes obtained by printing the gas diffusion layer in Example 2 of the present invention; Figure 5 Schematic diagram of the straight through holes obtained by printing the gas diffusion layer in Example 3 of the present invention and the tapered circular holes obtained by laser perforation. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below through specific implementation modes and in conjunction with the accompanying drawings, but the scope of the present invention is not limited to the following examples, and all specific changes made according to the present invention should be included in the protection scope of the present invention. Example 1

[0021] As shown in FIG1 , the present invention provides a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, comprising a main body 1, an air intake channel 2, and a drainage channel 3; A plurality of through holes are vertically arranged on the main body 1 according to a preset arrangement rule, and the through holes include large through holes and small through holes; the large through holes are air intake channels, and the small through holes are drainage channels; The air intake channel and the drainage channel are arranged separately from each other.

[0022] The air inlet channels are arranged in a row and column matrix, and the cross section of the air inlet channels is square or circular, with a side length or diameter of 1000 nanometers to 1000 micrometers. The aperture of the air inlet channels is not too large to weaken the mechanical strength and conductivity, and can effectively support the catalyst particles of the catalytic layer.

[0023] Outside the space occupied by the air inlet channel, the drainage channels are arranged in a matrix of rows and columns. The cross-section of the drainage channels is square or circular, and the side length or diameter is 10-1000 nanometers. When the side length or diameter is between 100-500 nanometers, the capillary effect is more significant, which helps to improve the efficiency of water discharge and ensures that the pore sizes of large and small pores are reasonably distributed at different scales; like Figure 2 As shown, the present embodiment provides a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, having separate air intake channel 5 and drainage channel 6, the main body 4 being obtained by 3D printing, and the cross-sections of the air intake channel and the drainage channel being through holes having the same shape and size in the depth direction.

[0024] At the same time, this embodiment provides a method for preparing a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, comprising the following steps: S1. preparing ink as a raw material for a gas diffusion layer; Prepare a mixed solution: weigh 0.25g of acetylene black and 0.25g of carbon nanotubes as conductive carbon materials, and 0.5g of PVP powder as a dispersant and binder, mix and grind for 5 minutes to make the particles uniform and fine; weigh 9g of deionized water, set the speed of the magnetic stirrer to 600r / min, slowly add the mixed powder during the stirring process, and continue stirring for about 5 minutes to fully disperse the powder to obtain a mixed solution; weigh 0.2g of carbon nanotube dispersant and add it to the mixed solution; weigh 0.3g of hydroxyethyl cellulose as a thickener and add it to the mixed solution at a magnetic stirring speed of 600r / min; Ultrasonic oscillation: Place the mixed solution in a beaker, seal the beaker with plastic wrap, and place the beaker in an ultrasonic cleaner. Perform ultrasonic oscillation at 100% power for 2 hours to evenly disperse the components in the solution. Magnetic stirring: After the ultrasonic treatment, set the magnetic stirrer speed to 1000 r / min and continue stirring for 12 h; Degassing and stirring: Degassing and stirring at a speed of 500 r / min for 10 min can effectively remove the bubbles in the ink, thereby obtaining a gas diffusion layer slurry that can be directly used for ink direct writing 3D printing.

[0025] S2. Using an ink direct writing 3D printing method, a gas diffusion layer with a gas-liquid separation path is prepared; Use SolidWorks software to build a 3D model: Create a cuboid model with a size of 30×30×0.1mm in SolidWorks, and evenly arrange large square through holes with a side length of 0.6mm inside the 3D model according to the set rules, and then export the STL format file; Set slicing parameters: import the above STL format file into the preset slicing software, and set the slicing parameters in the slicing software, including slicing fill rate 90%, printing needle diameter 0.06mm, and printing layer height 0.05mm; after slicing, the software automatically generates 2 layers of printing, each layer is filled with parallel lines, and the filling lines of the two adjacent layers are arranged vertically; the large square through hole designed in the modeling process is the air intake channel, and the small through hole generated by slicing is the drainage channel. After completing the slicing settings, export the G-code code file; 3D printing production: load the ink into the syringe, and connect a 0.06mm needle to the bottom of the syringe; then, install the syringe on the mobile robot arm of the printer, import the G-code code into the printing software, and set the printing parameters, including extrusion pressure of 350MPa and moving speed of 40mm / s; use a PEN film with adsorption function as the printing substrate during printing, so that the substrate can be firmly adsorbed on the printing platform during the printing process to avoid displacement of the substrate. At the same time, set the heating temperature of the printing substrate to 60°C. After each layer of printing is completed, raise the z-axis by 0.05mm. The printing parameters are the same, and the second and third layers are printed in turn.

[0026] S3, post-processing: hydrophobic sintering and drying of the printed samples; Preparation of 5% PTFE emulsion: Calculate the mass of deionized water required to prepare 60% PTFE emulsion by mass percentage, add a certain amount of deionized water to 60% PTFE emulsion, stir and dilute, and obtain 5% PTFE emulsion; Spray PTFE emulsion and preliminarily dry: Place the printed gas diffusion layer in a culture dish, and use an ultrasonic spraying device to evenly spray 5% PTFE emulsion on the surface of the printed sample; After spraying on the front side, cover the sample surface with a glass slide to prevent warping, and put it into a vacuum drying oven together with the culture dish, set the vacuum drying oven temperature to 60°C, dry for 15 min, then take it out and perform the same spraying operation on the back side, and repeat the above spraying and drying experimental process twice; Sinter the sample: put the printed sample after the above treatment into a quartz boat, use a long hook to put the quartz boat containing the sample into the middle position of the tube furnace to ensure the accuracy of the heating temperature; under the nitrogen atmosphere protection environment, check the gas path and set the sintering program after confirming that it is correct. The room temperature reaches 250°C at a heating rate of 5.5°C / min and is maintained for 20 minutes. After 30 minutes, the temperature is increased to 350°C and maintained for 30 minutes. Finally, it is cooled to room temperature at a rate of 5°C / min. When the temperature of the tube furnace is lower than 200°C, the lid of the tube furnace can be opened to cool it down quickly. When the temperature drops to room temperature, take out the sample to complete the hydrophobicization and drying treatment of the sample.

[0027] The straight-through hole design of the drainage channel utilizes the capillary effect to promote the discharge of water outward while ensuring smooth gas transmission. This structure can effectively realize gas-liquid separation transmission and maintain efficient gas transmission and water management under different working conditions. Example 2

[0028] This embodiment provides a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, comprising a main body 1, an air intake channel 2, and a drainage channel 3; A plurality of through holes are vertically arranged on the main body 1 according to a preset arrangement rule, and the through holes include large through holes and small through holes; the large through holes are air intake channels, and the small through holes are drainage channels; The air intake channel and the drainage channel are arranged separately from each other.

[0029] Structure Figure 4 As shown, it has a separate air intake channel 8 and a drainage channel 9, and the main body 7 is obtained by 3D printing. Figure 3 is a plan view of the gas diffusion layer obtained in this embodiment under an optical microscope, wherein Figure 3 (a) shows the structure and grid arrangement of the main body, and Figure 3 (b) shows the morphological characteristics of the material after the ink 3D printing is completed and the gradient effect of the material transmission channel. The main body is a thin sheet structure, and the material is a composite material composed of a variety of materials such as conductive carbon material, dispersant, binder, thickener, etc. The cross-section of the air intake channel and the drainage channel is a gradient hole whose shape remains unchanged in the depth direction but whose size gradually decreases.

[0030] A method for preparing a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission comprises the following steps: S1. Preparation of ink: same as in Example 1.

[0031] S2. Preparation of a gas diffusion layer having a gas-liquid separation passage: Use SolidWorks software to build a three-dimensional model: create a rectangular model with a size of 30×30×0.1mm in SolidWorks, and evenly arrange large square through holes with a side length of 0.6mm inside the three-dimensional model according to preset rules; then export the STL format file.

[0032] Set slicing parameters: import the above STL format file into the preset slicing software, set the slicing parameters in the slicing software, the slicing parameters include slicing fill rate 90%, printing needle diameter 0.06mm, printing layer height 0.05mm; after slicing, the slicing software automatically generates 2 layers of printing, each layer is filled with parallel lines, and the filling lines of the two adjacent layers are arranged vertically; the large square hole designed in the modeling process is the air intake channel, and the small through hole generated by slicing is the drainage channel. After completing the slicing settings, export the G-code code file; 3D printing production: ink is loaded into a syringe, and a 0.06mm needle is connected to the bottom of the syringe; then, the syringe is installed on the mobile arm of the printer, the G-code code is imported into the printing software, and the printing parameters of the first layer are set, including an extrusion pressure of 400MPa and a moving speed of 40mm / s; a PEN film with an adsorption function is used as a printing substrate during printing, so that the substrate can be firmly adsorbed on the printing platform during the printing process to avoid displacement of the substrate, and at the same time, the heating temperature of the printing substrate is set to 60°C; after completing one layer of printing, the z-axis is raised by 0.05mm, and the second layer printing parameters are set: extrusion pressure of 350MPa, moving speed of 40mm / s, the z-axis is raised by 0.05mm, and the third layer printing parameters are reset: extrusion pressure of 300MPa, moving speed of 40mm / s; by keeping the printing position and path unchanged, the center line of each extruded line is aligned in the z-axis direction, and the extrusion pressure and needle moving speed of each layer are adjusted at the same time, so that the printed lines of the new layer are thinner than those of the previous layer, thereby forming a regular gradient pore structure with a fixed pore size.

[0033] S3, post-processing process: the same as in Example 1.

[0034] The gradient hole design of the drainage through hole utilizes the change in hole size to enhance the capillary effect, promote the discharge of water, and ensure smooth gas transmission. This structure can better control the gas-liquid separation process and maintain efficient gas transmission and water management under different working conditions. Example 3 This embodiment provides a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, comprising a main body 1, an air intake channel 2, and a drainage channel 3; A plurality of through holes are vertically arranged on the main body 1 according to a preset arrangement rule, and the through holes include large through holes and small through holes; the large through holes are air intake channels, and the small through holes are drainage channels; The air intake channel and the drainage channel are arranged separately from each other.

[0035] Structure Figure 5 As shown, it has a separate air intake channel 11 and a drainage channel 12, the main body 10 is obtained by 3D printing, and the material transmission channel is obtained by laser perforation; The cross section of the air inlet channel is a through hole with the same shape and size in the depth direction, and the cross section of the drainage channel is a tapered circular hole in the depth direction.

[0036] A method for preparing a fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission comprises the following steps: S1. Preparation of ink: same as in Example 1.

[0037] S2. Preparation of a gas diffusion layer having a gas-liquid separation passage: Use SolidWorks software to build a three-dimensional model: create a rectangular model with a size of 30×30×0.2mm in SolidWorks, and then export it to an STL format file.

[0038] Set slicing parameters: Import the above STL format file into the preset slicing software, and set the following parameters in the software: the slice filling rate is set to 40%, the needle thickness is set to 0.16mm, and the printing layer height is set to 0.1mm; after slicing, generate 2 layers of printing layers, each layer is filled with parallel lines, and the filling lines of the two adjacent layers are arranged vertically, and then export the G-code code; 3D printing production: load the ink into the syringe and connect a 0.16mm needle to the bottom of the syringe; then, install the syringe on the mobile arm of the printer, import the G-code into the printing software, and set the printing parameters: extrusion pressure 350MPa, moving speed 40mm / s; use a PEN film with adsorption function as the printing substrate during printing to ensure that the substrate can be firmly adsorbed on the printing platform during the printing process to avoid displacement of the substrate. At the same time, set the heating temperature of the printing substrate to 60℃; after each layer of printing is completed, raise the z-axis by 0.1mm, and print the second and third layers in turn with the same printing parameters.

[0039] Laser perforation: After printing is completed, laser perforation is used to obtain nanoscale conical gradient holes according to the set arrangement rules. The large through holes generated by 3D printing are used as air intake channels, and the small through holes generated by laser perforation are used as drainage channels.

[0040] S3, post-processing process: the same as in Example 1.

[0041] The tapered hole structure of the drainage holes utilizes a gradually decreasing hole size design to reduce liquid residence time and accelerate water discharge while maintaining smooth gas transmission. This structure can better control the gas-liquid separation process and maintain efficient gas transmission and water management under different working conditions.

[0042] The above implementation modes are not limitations of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by technicians in this technical field within the scope of the technical solution of the present invention also belong to the protection scope of the present invention.

Claims

1. A fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission, characterized in that: It comprises a main body, on which a plurality of through holes are vertically arranged according to a preset arrangement rule, wherein the through holes comprise large through holes and small through holes; the large through holes are air intake channels, and the small through holes are drainage channels; the air intake channels and the drainage channels are arranged separately from each other.

2. A fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 1, characterized in that: The air inlet channels are arranged in a row and column matrix, and the cross-section of the air inlet channels is square or circular, with a side length or diameter of 1000 nanometers to 1000 micrometers; Outside the space occupied by the air inlet channel, the drainage channels are arranged in a row and column matrix, and the cross-section of the drainage channels is square or circular, with a side length or diameter of 10-1000 nanometers.

3. A fuel cell gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 1, characterized in that: The cross-sections of the air intake channel and the drainage channel are through holes with the same shape and size in the depth direction; or the cross-sections of the air intake channel and the drainage channel are gradient holes with the same shape in the depth direction but gradually decreasing size; or the cross-sections of the air intake channel and the drainage channel are tapered circular holes in the depth direction.

4. A method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission, characterized in that: The following steps are involved: S1. preparing ink as a raw material for a gas diffusion layer; S2. Using an ink direct writing 3D printing method, a gas diffusion layer with a gas-liquid separation path is prepared; S3. Perform hydrophobic sintering and drying treatment on the printed samples.

5. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 4, wherein in step S1, the method comprises the following steps: S11, weighing a set proportion of conductive carbon material, dispersant, binder, and thickener, and mixing them with deionized water in a set order to obtain a mixed solution; S12, subjecting the mixed solution to ultrasonic oscillation in an ultrasonic cleaner to disperse and fully mix the components in the mixed solution; S13, continue stirring with a magnetic stirrer to make the ink slurry after ultrasonic treatment more evenly dispersed; S14. Use a degassing stirring device to remove the bubbles remaining in the ink to obtain a raw material that can be directly used for ink direct writing 3D printing.

6. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 4, characterized in that: In step S2, 3D printing includes the following steps: S21, establishing a three-dimensional model according to the structure to be printed, and saving the three-dimensional model as an STL format file; S22, importing the STL format file into the slicing software for slicing processing, setting slicing parameters, and exporting the G-code format file; the slicing parameters include slicing fill rate, printing needle diameter, and printing layer height; S23, import the G-code format file into the printing software connected to the printer, adjust the extrusion pressure and printing speed, and start the printing process.

7. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 6, characterized in that: The large square through holes are evenly arranged inside the three-dimensional model according to a preset rule. The large square through holes are air intake channels, and the small through holes generated by slicing are drainage channels.

8. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 6, characterized in that: After printing is completed, laser perforation is used to obtain nano-scale conical gradient holes according to the set arrangement rules. The large through holes generated by 3D printing are used as air intake channels, and the small through holes generated by laser perforation are used as drainage channels.

9. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 6, characterized in that: The printing layer height is 2-5 layers; the thickness of the gas diffusion layer is 200-600 microns.

10. The method for preparing a gas diffusion layer capable of realizing gas-liquid separation and transmission according to claim 4, characterized in that: In step S3, the following steps are included: S31, preparing a hydrophobic agent solution with a set mass percentage; S32, using ultrasonic spraying equipment to control the diameter of particles during the spraying process so that the hydrophobic agent is evenly dispersed on the surface of the diffusion layer; S33, after the spraying is completed, the sample is placed in a vacuum drying oven for drying to preliminarily remove the residual moisture in the printed sample; S34. Under the set inert gas protection environment, place the sample in a tube furnace and control the heating process to melt the hydrophobic agent and bond it to the sample surface, while completely removing residual moisture.

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