A gas diffusion layer for fuel cells capable of gas-liquid separation and transport and its preparation method.

Abstract

This invention discloses a gas diffusion layer for a fuel cell capable of gas-liquid separation and transport, and its preparation method. The gas diffusion layer includes a main body with multiple through holes vertically arranged according to a preset rule. These through holes include large and small through holes; the large through holes serve as air inlet channels, and the small through holes serve as drainage channels; the air inlet channels and drainage channels are separated from each other. By designing the hole size, the water generated in the reaction can be preferentially discharged through the water channel in a timely manner, ensuring a timely supply of fuel gas and guaranteeing the separation and transport of gas and product water, thereby improving the durability and stability of the fuel cell.

Description

Technical Field

[0001] This invention relates to a gas diffusion layer for fuel cells that enables gas-liquid separation and transport, belonging to the field of proton exchange membrane fuel cell technology. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs), as a type of low-temperature fuel cell, not only boast high energy conversion efficiency and environmental friendliness but also relatively long lifespan, making them one of the most promising new energy devices to replace traditional energy sources. A PEMFC mainly comprises four core components: bipolar plates, a gas diffusion layer, a catalyst layer, and a proton exchange membrane. The gas diffusion layer (GDL) functions as an electrical and thermal conductor, supports the catalyst layer, and handles gas and water transport. Besides smoothly transporting the gas from the bipolar plates to the catalyst layer, the cathode GDL also needs to promptly drain the water generated during the reaction on one side of the cathode catalyst layer to ensure stable battery operation and provide power to external loads. If the reaction product water cannot be drained in time, it will clog the pores of the GDL, affecting gas supply and, in severe cases, even causing flooding, ultimately forcing the battery to stop working. Therefore, as the primary entity responsible for water management, the rational design of the gas diffusion layer plays a crucial role in ensuring gas transmission efficiency and stable battery operation.

[0003] Chinese invention patent CN114335571A discloses a gas diffusion layer, in which the cathode diffusion layer features a gradient design of material porosity and pore diameter. This cathode diffusion layer contains multiple pore structures, with the porosity increasing gradient along the fluid flow direction. Simultaneously, several through-holes are designed in the portion of the cathode diffusion layer corresponding to the cathode flow channel, and the pore diameter of these through-holes also increases gradient along the fluid flow direction. This gradient design of the gas diffusion layer improves water management performance; however, relying solely on the porosity gradient of the material itself may not completely prevent flooding, and the gradient design of the pore diameter only applies in the planar direction, offering little benefit for drainage in the vertical direction.

[0004] Chinese invention patent CN113241448A discloses a gradient microporous gas diffusion layer for proton exchange membrane fuel cells (GDLs) and its preparation method. This gas diffusion layer utilizes the geometric differences between different carbon materials to construct a microporous layer with a gradient pore size structure. Furthermore, it utilizes variations in polytetrafluoroethylene (PTFE) concentration to construct a gradient hydrophilic-hydrophobic structure, resulting in a gradient microporous gas diffusion layer with ordered hydrophilic-hydrophobic structures and a gradually changing pore distribution. While the gradient pore size and gradient hydrophilic-hydrophobic structure of this gas diffusion layer can reduce the flooding probability of GDLs, the gradient pore size achieved by the material itself is prone to forming blind pores, limiting the uniform distribution and effective drainage of moisture within the diffusion layer.

[0005] GDL's research focuses on improving water management capabilities. Current research primarily concentrates on the gradient design of material porosity and hydrophobicity, without differentiating the design of air intake and drainage channels. At high current densities, water is generated faster and in greater quantities. When most pores are occupied by water, gas transport is restricted, resulting in insufficient fuel supply, reduced reaction rates, or even reaction interruption. Summary of the Invention

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

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A gas diffusion layer for a fuel cell capable of gas-liquid separation and transmission includes a main body with multiple through holes vertically arranged according to a preset rule. The through holes include large through holes and small through holes. The large through holes are air inlet channels, and the small through holes are water outlet channels. The air inlet channels and water outlet channels are separated from each other.

[0009] The aforementioned fuel cell gas diffusion layer that enables gas-liquid separation and transmission has an intake channel arranged in a row and column matrix, and the intake channel has a square or circular cross-section with a side length or diameter of 1000 nanometers to 1000 micrometers.

[0010] In addition to the space occupied by the air intake channel, the drainage channels are arranged in a row and column matrix. The cross-section of the drainage channels is square or circular, with a side length or diameter of 10-1000 nanometers.

[0011] In the aforementioned fuel cell gas diffusion layer capable of gas-liquid separation and transmission, the inlet and outlet channels have cross-sections of through holes with the same shape and size in the depth direction; or the inlet and outlet channels have cross-sections of gradient holes with unchanged shape but gradually decreasing size in the depth direction; or the inlet and outlet channels have cross-sections of conical circular holes in the depth direction.

[0012] A method for preparing a gas diffusion layer capable of gas-liquid separation and transport includes the following steps:

[0013] S1. Prepare ink as a raw material for the gas diffusion layer;

[0014] S2. Using ink direct writing 3D printing method, prepare a gas diffusion layer with gas-liquid separation channel;

[0015] S3. Perform hydrophobic sintering and drying on the printed sample.

[0016] The aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport includes the following steps in step S1:

[0017] S11. Weigh out the conductive carbon material, dispersant, binder, and thickener in the specified proportions, and mix them with deionized water in the specified order to obtain a mixed solution.

[0018] S12. The mixed solution is subjected to ultrasonic oscillation in an ultrasonic cleaner to disperse and fully mix the components in the mixed solution;

[0019] S13. Continue stirring with a magnetic stirrer to make the ultrasonically treated ink slurry more evenly dispersed.

[0020] S14. Use a degassing and stirring device to remove residual air bubbles from the ink to obtain raw materials that can be directly used for ink-to-ink 3D printing.

[0021] In the aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport, step S2 involves 3D printing comprising the following steps:

[0022] S21. Create a three-dimensional model based on the structure to be printed, and save the three-dimensional model as an STL format file;

[0023] S22. Import the STL format file into the slicing software for slicing processing, set the slicing parameters, and export the G-code format file; the slicing parameters include the slice fill rate, the printing needle diameter, and the printing layer height;

[0024] 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.

[0025] The aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport involves uniformly arranging large square through holes according to pre-set rules inside a three-dimensional model. These large square through holes serve as air inlet channels, while the small through holes generated by slicing serve as drainage channels.

[0026] The aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport involves obtaining nanoscale conical gradient holes by laser perforation according to a set arrangement rule after printing. The large through-holes generated by 3D printing serve as air inlet channels, while the small through-holes generated by laser perforation serve as drainage channels.

[0027] The aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport involves printing 2-5 layers; the thickness of the gas diffusion layer is 200-600 micrometers.

[0028] The aforementioned method for preparing a gas diffusion layer capable of gas-liquid separation and transport includes the following steps in step S3:

[0029] S31. Prepare a hydrophobic agent solution with a specified mass percentage;

[0030] S32. Use 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.

[0031] S33. After the spraying is completed, the sample is placed in a vacuum drying oven for drying treatment to initially remove residual moisture from the printed sample;

[0032] S34. Under the set inert gas protection environment, place the sample into a tube furnace, control the heating process, so that the hydrophobic agent melts and adheres to the sample surface, while completely removing residual moisture.

[0033] The beneficial effects achieved by the present invention are as follows: The gas diffusion layer of the present invention, which enables gas-liquid separation and transmission, is provided with pores of different sizes in its structure. Small pores are used for drainage, and large pores are used for gas intake. Since the small pores can attract water more effectively by utilizing capillary action, the water generated by the reaction is preferentially guided to the drainage channel, thereby forming a gas-liquid separation transmission path to ensure the timely removal of reaction product water and the timely supply of fuel gas, thereby improving the stability of battery operation.

[0034] The present invention discloses a method for preparing a gas diffusion layer for a fuel cell that enables gas-liquid separation and transport. The gas-liquid separation and transport channels formed are ordered. The main body is manufactured using 3D printing technology, and the internal material transport channels are formed by pre-designed 3D printing holes or laser perforation. Therefore, the overall structure is ordered, and the size of the holes can be precisely controlled. Attached Figure Description

[0035] Figure 1(a) is a top view of the gas diffusion layer in Embodiment 1 of the present invention;

[0036] Figure 1(b) is a front view of the gas diffusion layer in Embodiment 1 of the present invention;

[0037] Figure 2 This is a schematic diagram of the through-hole obtained by printing the gas diffusion layer in Embodiment 1 of the present invention;

[0038] Figure 3(a) is a schematic diagram of the structure and grid arrangement of the main body of the gas diffusion layer obtained by ink 3D printing in Embodiment 2 of the present invention under an optical microscope;

[0039] Figure 3(b) is a diagram showing the morphological features of the material and the gradient effect of the material transport channels after ink 3D printing in Embodiment 2 of the present invention;

[0040] Figure 4 This is a schematic diagram of the gradient through-holes obtained by printing the gas diffusion layer in Embodiment 2 of the present invention;

[0041] Figure 5 This is a schematic diagram of the through hole obtained by printing the gas diffusion layer in Embodiment 3 of the present invention and the conical hole obtained by laser perforation. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. However, the scope of the present invention is not limited to the following examples, and all specific modifications made according to the present invention should be included within the scope of protection of the present invention. Example 1

[0043] As shown in Figure 1, the present invention provides a gas diffusion layer for a fuel cell that enables gas-liquid separation and transmission, comprising a main body 1, an air inlet channel 2, and a drainage channel 3;

[0044] Multiple through holes are vertically arranged on the main body 1 according to a preset arrangement rule. 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.

[0045] The air intake channel and the drainage channel are set separately.

[0046] The air intake channels are arranged in a row and column matrix, and the cross-section of the air intake channels is square or circular, with a side length or diameter of 1000 nanometers to 1000 micrometers. The aperture of the air intake channels is neither too large to weaken mechanical strength and conductivity, nor too small to effectively support the catalyst particles of the catalyst layer.

[0047] In addition to the space occupied by the air intake channel, the drainage channels are arranged in a row and column matrix. The cross-section of the drainage channels is square or circular, with a side length or diameter of 10-1000 nanometers. When the side length or diameter is between 100-500 nanometers, capillary action is more significant, which helps to improve the water discharge efficiency and ensures that the pore sizes of large and small holes are reasonably distributed at different scales.

[0048] like Figure 2 As shown, this embodiment provides a fuel cell gas diffusion layer that enables gas-liquid separation and transmission, having separate air intake channels 5 and drainage channels 6. The main body 4 is obtained by 3D printing, and the cross-sections of the air intake channels and drainage channels are through holes with the same shape and size in the depth direction.

[0049] Meanwhile, this embodiment provides a method for preparing a fuel cell gas diffusion layer that enables gas-liquid separation and transport, including the following steps:

[0050] S1. Prepare ink as a raw material for the gas diffusion layer;

[0051] Preparation of the 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 dispersant and binder. Mix and grind for 5 minutes to make the particles uniform and fine. Weigh 9g of deionized water, set the magnetic stirrer speed to 600r / min, and slowly add the mixed powder during stirring. Continue stirring for about 5 minutes to fully disperse the powder and obtain the mixed solution. Weigh 0.2g of carbon nanotube dispersant and add it to the mixed solution. Weigh 0.3g of hydroxyethyl cellulose as thickener and add it to the mixed solution with a magnetic stirring speed of 600r / min.

[0052] 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 ensure that the components in the solution are evenly dispersed.

[0053] Magnetic stirring: After ultrasonication, set the magnetic stirrer speed to 1000 r / min and continue stirring for 12 hours;

[0054] Degassing and stirring: Degas and stir at 500 r / min for 10 min to effectively remove air bubbles from the ink, thereby obtaining a gas diffusion layer slurry that can be directly used for ink direct writing 3D printing.

[0055] S2. Using ink direct writing 3D printing method, prepare a gas diffusion layer with gas-liquid separation channel;

[0056] To create a 3D model using SolidWorks software: Create a cuboid model with dimensions 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 it as an STL format file.

[0057] Set slicing parameters: Import the above STL format file into the preset slicing software, and set the slicing parameters in the slicing software. The slicing parameters include a slice fill rate of 90%, a print head diameter of 0.06 mm, and a print layer height of 0.05 mm. After slicing, the software automatically generates two print layers. The fill method of each layer is parallel lines, and the fill lines of adjacent layers are arranged perpendicularly. The large square through-hole designed during 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 file.

[0058] 3D printing process: Ink is loaded into a syringe, and a 0.06mm needle is attached to the bottom of the syringe. Next, the syringe is mounted on the printer's moving robotic arm. The G-code is imported into the printing software, and the printing parameters are set, including an extrusion pressure of 350MPa and a moving speed of 40mm / s. During printing, a PEN film with adsorption function is used as the printing substrate, which can firmly adhere to the printing platform during the printing process to prevent substrate displacement. At the same time, the heating temperature of the printing substrate is set to 60℃. After each layer is printed, the z-axis is raised by 0.05mm, and the printing parameters are the same. The second and third layers are printed in sequence.

[0059] S3. Post-processing: Perform hydrophobic sintering and drying on the printed samples;

[0060] To prepare a 5% PTFE emulsion: Calculate the mass of deionized water required to prepare a 60% PTFE emulsion using the mass percentage method. Add a measured amount of deionized water to the 60% PTFE emulsion, stir, and dilute to obtain a 5% PTFE emulsion.

[0061] Spraying PTFE emulsion and initial drying: Place the printed gas diffusion layer into a petri dish, and use an ultrasonic spraying device to evenly spray 5% PTFE emulsion onto the surface of the printed sample; after spraying the front side, cover the sample surface with a glass slide to prevent warping, and place it together with the petri dish into a vacuum drying oven. Set the temperature of the vacuum drying oven to 60°C and dry for 15 minutes. Then take it out and perform the same spraying operation on the reverse side. Repeat the above spraying and drying experiment twice.

[0062] Sintering the sample: Place the printed sample after the above treatment into a quartz boat. Use a long hook to place the quartz boat containing the sample into the middle position of the tube furnace to ensure accurate heating temperature. Under nitrogen atmosphere protection, after checking the gas path and confirming that it is correct, set the sintering program. The room temperature is raised to 250°C at a rate of 5.5°C / min and held for 20 minutes. Then, after 30 minutes, the temperature is raised to 350°C and held for 30 minutes. Finally, the temperature is lowered to room temperature at a rate of 5°C / min. When the temperature of the tube furnace is below 200°C, the tube furnace lid can be opened for rapid cooling. When the temperature drops to room temperature, the sample is taken out to complete the hydrophobication and drying treatment of the sample.

[0063] The straight-through hole design of the drainage channel utilizes the capillary effect to promote the outward discharge of water while ensuring smooth gas transmission. This structure can effectively achieve gas-liquid separation and transmission, maintaining efficient gas transmission and water management under different working conditions. Example 2

[0064] This embodiment provides a fuel cell gas diffusion layer that enables gas-liquid separation and transmission, including a main body 1, an air inlet channel 2, and a drainage channel 3;

[0065] Multiple through holes are vertically arranged on the main body 1 according to a preset arrangement rule. 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.

[0066] The air intake channel and the drainage channel are set separately.

[0067] Structure as Figure 4 As shown, the main body 7 has separate air intake channels 8 and drainage channels 9, and is obtained by 3D printing. Figure 3 is a planar view of the gas diffusion layer obtained in this embodiment under an optical microscope. Figure 3(a) shows the structure and grid arrangement of the main body, and Figure 3(b) shows the morphological characteristics of the material and the gradient effect of the material transport channels after ink 3D printing. The main body is a sheet-like structure, and the material is a composite material composed of conductive carbon material, dispersant, binder, thickener and other materials. The cross-section of the air intake channel and the drainage channel is a gradient hole with a constant shape in the depth direction but a gradually decreasing size.

[0068] A method for preparing a gas diffusion layer for a fuel cell capable of gas-liquid separation and transport includes the following steps:

[0069] S1. Preparation of ink: Same as in Example 1.

[0070] S2. Preparation of a gas diffusion layer with a gas-liquid separation pathway:

[0071] To create a 3D model using SolidWorks software: Create a cuboid model with dimensions 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 preset rules; then export it as an STL format file.

[0072] Set slicing parameters: Import the above STL format file into the preset slicing software, and set the slicing parameters in the slicing software. The slicing parameters include a slice fill rate of 90%, a print head diameter of 0.06 mm, and a print layer height of 0.05 mm. After slicing, the slicing software automatically generates two print layers. The fill method of each layer is parallel lines, and the fill lines of adjacent layers are arranged perpendicularly. The large square hole designed during the modeling process is the air intake channel, and the small hole generated by slicing is the drainage channel. After completing the slicing settings, export the G-code file.

[0073] 3D Printing Process: Ink is loaded into a syringe, with a 0.06mm needle attached to the bottom. The syringe is then mounted on the printer's moving robotic arm. G-code is imported into the printing software, and the printing parameters for the first layer are set, including an extrusion pressure of 400MPa and a moving speed of 40mm / s. A PEN film with adsorption properties is used as the printing substrate to ensure it adheres firmly to the printing platform, preventing displacement. The substrate heating temperature is set to 60℃. After one layer is printed, the z-axis is raised by 0.05mm, and the second layer printing parameters are set: an extrusion pressure of 350MPa and a moving speed of 40mm / s. The z-axis is then raised by 0.05mm again, and the third layer printing parameters are reset to: an extrusion pressure of 300MPa and a moving speed of 40mm / s. By maintaining the printing position and path, the center lines of each extruded line are aligned along the z-axis. Adjusting the extrusion pressure and needle moving speed of each layer results in thinner lines in each new layer, creating a regular gradient hole structure with fixed apertures.

[0074] S3. Post-processing: Same as in Example 1.

[0075] The gradient orifice design of the drainage through-hole enhances the capillary effect by utilizing the change in orifice size, promoting the outward discharge of water while ensuring unobstructed gas transmission. This structure allows for better control of the gas-liquid separation process, maintaining efficient gas transmission and water management under different operating conditions. Example 3

[0076] This embodiment provides a fuel cell gas diffusion layer that enables gas-liquid separation and transmission, including a main body 1, an air inlet channel 2, and a drainage channel 3;

[0077] Multiple through holes are vertically arranged on the main body 1 according to a preset arrangement rule. 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.

[0078] The air intake channel and the drainage channel are set separately.

[0079] Structure as Figure 5 As shown, it has separate air intake channel 11 and drainage channel 12. The main body 10 is obtained by 3D printing, and the material transport channel is obtained by laser perforation.

[0080] The air intake channel has a cross-section that is a through hole with the same shape and size in the depth direction, and the drainage channel has a cross-section that is a tapered circular hole in the depth direction.

[0081] A method for preparing a gas diffusion layer for a fuel cell capable of gas-liquid separation and transport includes the following steps:

[0082] S1. Preparation of ink: Same as in Example 1.

[0083] S2. Preparation of a gas diffusion layer with a gas-liquid separation pathway:

[0084] To create a 3D model using SolidWorks software: Create a cuboid model with dimensions of 30×30×0.2mm in SolidWorks, and then export it as an STL file.

[0085] Set slicing parameters: Import the above STL format file into the preset slicing software, and set the following parameters in the software: slice fill rate is set to 40%, needle thickness is set to 0.16mm, and printing layer height is set to 0.1mm; after slicing, two printing layers are generated, each layer is filled with parallel lines, and the fill lines of adjacent layers are arranged vertically, and then the G-code code is exported.

[0086] 3D printing process: Ink is loaded into a syringe, and a 0.16mm needle is attached to the bottom of the syringe. Next, the syringe is mounted on the printer's moving robotic arm. The G-code is imported into the printing software, and the printing parameters are set as follows: extrusion pressure 350MPa, moving speed 40mm / s. During printing, a PEN film with adsorption function is used as the printing substrate to ensure that the substrate can be firmly adsorbed on the printing platform during the printing process, preventing the substrate from shifting. At the same time, the heating temperature of the printing substrate is set to 60℃. After each layer is printed, the Z-axis is raised by 0.1mm, and the printing parameters are the same. The second and third layers are printed in sequence.

[0087] Laser perforation: After printing, according to the set arrangement rules, laser perforation is used to obtain nanoscale conical gradient holes. The large through holes generated by 3D printing serve as air intake channels, and the small through holes generated by laser perforation serve as drainage channels.

[0088] S3. Post-processing: Same as in Example 1.

[0089] The tapered structure of the drainage orifice utilizes a gradually decreasing orifice size design to reduce liquid residence time, accelerate water discharge, and maintain unobstructed gas transmission. This structure can better control the gas-liquid separation process and maintain efficient gas transmission and water management under different operating conditions.

[0090] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention are also within the protection scope of the present invention.

Claims

1. A gas diffusion layer for a fuel cell capable of gas-liquid separation and transport, characterized in that, The device includes a main body, on which multiple through holes are vertically arranged according to a preset rule. 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 channels and drainage channels are separated from each other. The air intake channels are arranged in a row and column matrix, and the cross-section of the air intake channels is square or circular, with a side length or diameter of 1000 nanometers to 1000 micrometers; In addition to the space occupied by the air intake channel, the drainage channels are arranged in a row and column matrix. The cross-section of the drainage channels is square or circular, with a side length or diameter of 10-1000 nanometers.

2. The fuel cell gas diffusion layer capable of gas-liquid separation and transport according to claim 1, characterized in that, The air intake channel and the drain channel have cross-sections that are through holes with the same shape and size in the depth direction; or the air intake channel and the drain channel have cross-sections that are gradient holes with a constant shape in the depth direction but gradually decreasing size; or the air intake channel and the drain channel have cross-sections that are tapered circular holes in the depth direction.

3. A method for preparing a gas diffusion layer capable of gas-liquid separation and transport, characterized in that, Includes the following steps: S1. Prepare ink as a raw material for the gas diffusion layer; S2. Using ink-to-ink 3D printing, a gas diffusion layer with gas-liquid separation pathways is prepared. 3D printing includes the following steps: S21. Create a three-dimensional model based on the structure to be printed, and save the three-dimensional model as an STL format file; S22. Square large through holes are evenly arranged inside the three-dimensional model according to a preset rule. The square large through holes are air intake channels. Import the STL format file into the slicing software for slicing. The small through holes generated by slicing are drainage channels. Set the slicing parameters and export the G-code format file. The slicing parameters include the slice fill rate, the printing needle diameter, and the printing layer height. Alternatively, after printing the air intake channel, according to the set arrangement rules, use laser perforation to obtain nanoscale conical gradient holes. The large through holes generated by 3D printing serve as air intake channels, and the small through holes generated by laser perforation serve as drainage channels. 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; S3. Perform hydrophobic sintering and drying on the printed sample.

4. The method for preparing a gas diffusion layer capable of gas-liquid separation and transport according to claim 3, wherein step S1 includes the following steps: S11. Weigh out the conductive carbon material, dispersant, binder, and thickener in the specified proportions, and mix them with deionized water in the specified order to obtain a mixed solution. S12. The mixed solution is subjected 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 ultrasonically treated ink slurry more evenly dispersed; S14. Use a degassing and stirring device to remove residual air bubbles from the ink to obtain raw materials that can be directly used for ink-to-ink 3D printing.

5. The method for preparing a gas diffusion layer capable of gas-liquid separation and transport according to claim 3, characterized in that, The printing layer height is 2-5 layers; the thickness of the gas diffusion layer is 200-600 micrometers.

6. The method for preparing a gas diffusion layer capable of gas-liquid separation and transport according to claim 3, characterized in that, Step S3 includes the following steps: S31. Prepare a hydrophobic agent solution with a specified mass percentage; S32. Use 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 treatment to initially remove residual moisture from the printed sample; S34. Under the set inert gas protection environment, place the sample into a tube furnace, control the heating process, so that the hydrophobic agent melts and adheres to the sample surface, while completely removing residual moisture.

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