Flow field diffusion layer integrated structure, preparation method thereof and electrolytic bath

Abstract

The embodiment of the invention discloses a flow field diffusion layer integrated structure, a preparation method thereof and an electrolytic bath, and belongs to the technical field of water electrolysis hydrogen production, and the flow field diffusion layer integrated structure comprises a flow field structure, a gas diffusion layer and a first binder. The flow field structure and the gas diffusion layer are arranged in a stacked mode in the first direction, the first bonding layer is arranged between the flow field structure and the gas diffusion layer, and the material of the first bonding layer comprises at least one of nickel powder, titanium powder, nickel fibers, titanium fibers, a carbon-based material and a high polymer material. The flow field structure, the first bonding layer and the gas diffusion layer form an integrated structure. According to the flow field diffusion layer integrated structure, the mass transfer efficiency can be improved, the dynamic response performance is improved, the energy efficiency is guaranteed, and the service life is prolonged.

Description

Technical Field

[0001] This application relates to the field of hydrogen production technology by water electrolysis, specifically to an integrated structure of flow field diffusion layer and its preparation method, and an electrolyzer. Background Technology

[0002] With the advancement of dual-carbon goals, green hydrogen derived from solar and wind energy has become an important alternative to fossil fuels as a clean energy carrier. Anion exchange membrane electrolysis (AEMWE) combines the advantages of alkaline water electrolysis (ALK) and proton exchange membrane electrolysis (PEMWE), offering advantages such as low cost, low corrosion, high efficiency, and high dynamic response, making it suitable for large-scale renewable energy hydrogen production.

[0003] The core components of anion exchange membrane electrolyzer include anion exchange membranes (AEM), catalyst layers (CL), gas diffusion layers (GDL), flow fields, bipolar plates, and a sealing system. The gas diffusion layer provides an electron conduction path, promoting the transport of gas (hydrogen or oxygen) and liquid (alkaline solution or pure water). The flow field optimizes the flow of electrolyte and gas, preventing bubble blockage and increasing current density.

[0004] In related technologies, the gas diffusion layer and the flow field in anion exchange membrane electrolyzers are typically designed as separate components, assembled by mechanical pressing. Because the gas diffusion layer and the flow field are physically stacked and pressed together, micro-gaps exist at the interface, resulting in high contact resistance and low mass transfer efficiency. This negatively impacts hydrogen production efficiency and electrolyzer lifespan. Furthermore, the stringent requirements for processing and assembly precision hinder the development trend towards compact designs. Summary of the Invention

[0005] This application provides an integrated flow field diffusion layer structure and its preparation method, as well as an electrolytic cell, which can effectively reduce interfacial contact resistance and ohmic loss, eliminate mechanical contact surfaces, improve mass transfer efficiency, enhance dynamic response performance, and extend service life.

[0006] This application provides an integrated structure for a flow field diffusion layer, comprising: Flow field structure; A gas diffusion layer and a flow field structure are stacked along a first direction; A first adhesive layer is disposed between the flow field structure and the gas diffusion layer. The material of the first adhesive layer includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials. The flow field structure, the first bonding layer, and the gas diffusion layer form an integrated structure.

[0007] By integrating the flow field structure, the first bonding layer, and the gas diffusion layer into a single structure, the interfacial contact resistance and ohmic loss between the flow field structure and the gas diffusion layer can be reduced, mechanical contact surfaces between components can be eliminated, and service life can be extended. The first bonding layer, comprising at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials, can improve the mechanical contact between the flow field structure and the gas diffusion layer, effectively prevent local overheating, optimize the pore structure, and increase conductive contact points, thereby improving energy efficiency. Furthermore, the integrated flow field diffusion layer structure can optimize gas-liquid transport, shorten the electrolyte transport path, reduce liquid resistance, and improve dynamic response performance. In other words, the integrated flow field diffusion layer structure provided in this application can improve mass transfer efficiency, enhance dynamic response performance, ensure energy efficiency, and extend service life.

[0008] In some embodiments, the aperture of the flow field structure is P1, and the aperture of the gas diffusion layer is P2, where P1 > P2.

[0009] The pore size of the flow field structure is larger than that of the gas diffusion layer, forming a gradient pore structure. This flow field structure provides a larger flow channel volume, reduces gas-liquid flow resistance, and promotes the rapid and uniform distribution of reactants and products (hydrogen, oxygen, or electrolyte) throughout the entire flow field structure. The gas diffusion layer forms a denser pore network, increasing capillary forces within the diffusion layer and limiting excessive liquid permeation, thus maintaining unobstructed gas transport channels. Simultaneously, the gradient pore structure also helps to distribute stress more evenly, ensuring the mechanical strength of the integrated flow field diffusion layer structure.

[0010] In some embodiments, the thickness of the flow field structure is 0.3 mm to 3 mm; And / or, the aperture of the flow field structure is 10μm-2000μm.

[0011] By ensuring that the thickness and / or aperture of the flow field structure are within the aforementioned range, the mechanical stability of the flow field structure can be guaranteed, as well as the transport efficiency of gas and liquid in the flow field structure can be guaranteed.

[0012] In some embodiments, the thickness of the gas diffusion layer is 0.3 mm to 3 mm; And / or, the pore size of the gas diffusion layer is 0.5 μm-500 μm; And / or, the surface roughness Ra of the gas diffusion layer is 3μm-25μm; And / or, the areal density of the gas diffusion layer is 50 g / m³. 2 -3500g / m 2 .

[0013] The thickness, pore size, surface roughness, and / or areal density of the gas diffusion layer are within the above ranges, which can ensure the structural stability of the gas diffusion layer, the high energy conversion efficiency, and the transport efficiency of gas and liquid in the gas diffusion layer.

[0014] In some embodiments, the thickness of the first adhesive layer is 1 μm-50 μm.

[0015] The thickness of the first adhesive layer, within the aforementioned range, can enhance the interfacial bonding strength between the flow field structure and the gas diffusion layer, ensure uniform stress distribution, reduce interfacial resistance, improve conductivity, and optimize electron conduction.

[0016] In some embodiments, the flow field structure and the gas diffusion layer are made of the same material, or the flow field structure and the gas diffusion layer are made of different materials.

[0017] Using the same material ensures that the thermal expansion properties of the flow field structure and the gas diffusion layer are matched, reducing interfacial stress and simplifying the process of forming a single structure, thus reducing costs. Using dissimilar materials allows for functional differentiation between the flow field structure and the gas diffusion layer, optimizing properties such as gas transport, conductivity, and mechanical strength, which helps achieve high power density.

[0018] In some embodiments, the flow field structure includes multiple flow field sublayers stacked along a first direction; The aperture of the flow field structure decreases in the direction from the side furthest from the gas diffusion layer to the side closest to the gas diffusion layer.

[0019] In other words, within the flow field structure, the pore size of the flow field sublayer closer to the gas diffusion layer is smaller than that of the flow field sublayer farther from the gas diffusion layer, resulting in a gradient pore structure within the flow field structure. The smaller pore size of the flow field sublayer closer to the gas diffusion layer enhances gas distribution uniformity, while the larger pore size of the flow field sublayer farther from the gas diffusion layer provides large-aperture channels, reducing liquid flow resistance. This gradient pore flow field structure optimizes gas transport and liquid water management, improving the transport efficiency and service life of the flow field structure. The lower pore size of the flow field sublayer closer to the gas diffusion layer also enhances structural support, ensuring the mechanical strength of the integrated flow field diffusion layer structure.

[0020] In some embodiments, the multilayer flow field sublayers form an integral structure, and a second adhesive layer is provided between adjacent flow field sublayers; The second adhesive layer includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials.

[0021] The second bonding layer can improve the bonding force between the multi-layer flow field sub-layers, improve the mechanical contact performance between the multi-layer flow field sub-layers, increase the conductive contact points, and improve the structural stability, optimize the electrical conductivity, enhance the energy conversion efficiency, and extend the service life while ensuring that the flow field structure forms a gradient pore structure.

[0022] In some embodiments, the gas diffusion layer includes multiple gas diffusion sublayers stacked along a first direction, the multiple gas diffusion sublayers forming an integral structure, and a third adhesive layer is disposed between adjacent gas diffusion sublayers. The third adhesive layer includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials.

[0023] The integrated structure formed by multiple gas diffusion sublayers can improve the mechanical stability and durability of the gas diffusion layer. The third bonding layer disposed between adjacent gas diffusion sublayers can improve interlayer bonding, disperse stress, enhance resistance to mechanical deformation, and build a continuous electronic conduction network in the gas diffusion layer, reducing the contact resistance between layers.

[0024] In some embodiments, the integral structure of the flow field diffusion layer further includes a microporous layer, which is disposed on the side of the gas diffusion layer away from the flow field structure. The thickness of the microporous layer is 10μm-40μm, and the porosity is 20%-45%.

[0025] By setting a microporous layer, the distribution and transport of liquid can be optimized, while promoting gas and heat conduction, achieving efficient gas-liquid transport, which is beneficial for improving performance under high current density.

[0026] In some embodiments, the material of the microporous layer includes at least one of nickel-based metal powder, iron-based metal powder, titanium-based metal powder, and carbon-based powder.

[0027] Nickel-based metal powders, iron-based metal powders, titanium-based metal powders, and carbon-based powders all have good electronic conductivity, which helps to improve the distribution of reactants and current on the surface of the gas diffusion layer, improve reaction efficiency and extend service life, and can also optimize the interfacial contact effect, reduce contact resistance, and improve performance under high current density.

[0028] In some embodiments, the thickness of the integral flow field diffusion layer structure is 0.6 mm to 6 mm; And / or, the compressibility of the integrated flow field diffusion layer structure is 10%-80%; And / or, the areal density of the integral structure of the flow field diffusion layer is 1000 g / m³. 2 -5000g / m 2 ; And / or, the tensile strength of the integral flow field diffusion layer structure is 10MPa-200MPa; And / or, the compressive strength of the integrated flow field diffusion layer structure is 3MPa-150MPa.

[0029] By ensuring the thickness of the integrated flow field diffusion layer structure is within the aforementioned range, a balance can be struck between its gas transport efficiency and structural strength. By ensuring the compressibility of the integrated flow field diffusion layer structure is within the aforementioned range, effective interfacial contact between layers can be guaranteed, ensuring interfacial bonding strength. By ensuring the areal density of the integrated flow field diffusion layer structure is within the aforementioned range, the reaction contact area can be increased, contact resistance reduced, and mechanical stability enhanced. By ensuring the tensile strength of the integrated flow field diffusion layer structure is within the aforementioned range, assembly stress and vibration fatigue can be resisted, improving structural stability. By ensuring the compressive strength of the integrated flow field diffusion layer structure is within the aforementioned range, deformation can be resisted, ensuring the stability of the porous structure and guaranteeing gas-liquid transport efficiency.

[0030] In some embodiments, the flow field structure, the first adhesive layer, and the gas diffusion layer are formed into an integral structure by thermal sintering or laser welding.

[0031] Thermal sintering enables atomic diffusion between the flow field structure and the gas diffusion layer through the first bonding layer at high temperatures, forming a metallurgical bond and thus improving interfacial bonding performance. Laser welding utilizes high-energy laser melting to achieve instantaneous metallurgical bonding of the flow field structure, the first bonding layer, and the gas diffusion layer. Furthermore, the concentrated energy of laser welding reduces thermal stress accumulation and prevents pore collapse. Both thermal sintering and laser welding ensure effective interfacial bonding between layers. During thermal sintering or laser welding, the first bonding layer reduces interfacial stress generated by thermal cycling, guaranteeing bonding strength.

[0032] According to a second aspect of this application, a method for preparing an integral flow field diffusion layer structure is also provided, comprising: Provide flow field structure; A first adhesive layer and a gas diffusion layer are sequentially disposed on one side of the flow field structure in the first direction. After pressing, a composite structure is obtained. The composite structure is formed into an integral structure by thermal sintering or laser welding to obtain an integral flow field diffusion layer structure.

[0033] The method for preparing the integrated flow field diffusion layer structure provided in this application has all the beneficial effects of the integrated flow field diffusion layer structure as described above, and will not be repeated here.

[0034] In some embodiments, the method for preparing the flow field structure includes: A multilayer first substrate material layer is provided, the multilayer first substrate material layer is stacked along a first direction, a second adhesive layer is provided between adjacent first substrate material layers, roll forming is performed, and the multilayer first substrate material layer and the second adhesive layer are formed into an integral structure by thermal sintering or laser welding to obtain a flow field structure.

[0035] Roll forming of a first matrix material layer stacked together can improve the structural strength and stability of the flow field structure, and the use of first matrix materials with different pore sizes helps to achieve a gradient aperture in the flow field structure. A second bonding layer disposed between adjacent first matrix material layers can improve the bonding force between the multiple first matrix material layers during subsequent processes through thermal sintering or laser welding, improve the mechanical contact performance between layers, increase conductive contact points, and improve overall structural stability, optimize electrical conductivity, and increase energy conversion efficiency while ensuring the formation of a gradient porosity structure in the flow field. Thermal sintering technology enables atomic diffusion at high temperatures, forming a metallurgical bond and effectively improving interfacial bonding performance. Laser welding technology utilizes laser melting to achieve instantaneous metallurgical bonding, concentrating energy and reducing thermal stress accumulation.

[0036] In some embodiments, a first adhesive layer and a gas diffusion layer are sequentially disposed on one side of the flow field structure in a first direction, including: A first adhesive layer and multiple layers of second matrix material are sequentially disposed on the side with smaller aperture in the first direction of the flow field structure, and a third adhesive layer is disposed between adjacent second matrix material layers, and the structure is roll-formed.

[0037] The first bonding layer tightly connects the flow field structure and the multilayer second matrix material layer, while the third bonding layer effectively bonds adjacent second matrix material layers, forming a stable and reliable integrated structure while reducing interfacial resistance. The arrangement of multiple second matrix material layers increases the strength of the gas diffusion layer and improves its mechanical properties.

[0038] According to a third aspect of this application, an electrolytic cell is also provided, comprising an integral flow field diffusion layer structure as described above, and / or an integral flow field diffusion layer structure prepared by the method described above.

[0039] The electrolytic cell provided in this application has all the beneficial effects of the integrated flow field diffusion layer structure as described above, which will not be repeated here. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic cross-sectional view of the integrated flow field diffusion layer structure provided in the embodiments of this application; Figure 2 This is a comparison diagram of polarization curves in the embodiments and comparative examples of this application.

[0042] Explanation of reference numerals in the attached figures: 100. Integrated structure of flow field diffusion layer; 10. Flow field structure; 11. Flow field sublayer; 12. Second bonding layer; 20. Gas diffusion layer; 21. Gas diffusion sublayer; 22. Third bonding layer; 30. First bonding layer. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] This application provides an integrated flow field diffusion layer structure 100, its preparation method, and an electrolytic cell. These are described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative and do not impose numerical requirements or establish an order. Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0045] Firstly, such as Figure 1As shown, this application provides an integrated flow field diffusion layer structure 100, including a flow field structure 10, a gas diffusion layer 20, and a first adhesive layer 30. The gas diffusion layer 20 and the flow field structure 10 are stacked along a first direction X, and the first adhesive layer 30 is disposed between the flow field structure 10 and the gas diffusion layer 20. The material of the first adhesive layer 30 includes at least one selected from nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials. The flow field structure 10, the first adhesive layer 30, and the gas diffusion layer 20 form an integrated structure.

[0046] By integrating the flow field structure 10, the first adhesive layer 30, and the gas diffusion layer 20 into a single structure, the interfacial contact resistance and ohmic loss between the flow field structure 10 and the gas diffusion layer 20 can be reduced, the mechanical contact surfaces between the components can be eliminated, and the service life can be extended. The first adhesive layer 30, comprising at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based materials, can improve the mechanical contact between the flow field structure 10 and the gas diffusion layer 20, effectively prevent local overheating, optimize the pore structure, and increase conductive contact points, thereby improving energy efficiency. Furthermore, the integrated flow field diffusion layer structure 100 can optimize gas-liquid transport, shorten the electrolyte transport path, reduce liquid resistance, and improve dynamic response performance. In other words, the integrated flow field diffusion layer structure 100 provided in this application can improve mass transfer efficiency, enhance dynamic response performance, ensure energy efficiency, and extend service life.

[0047] In some embodiments, the pore size of the flow field structure 10 is P1, and the pore size of the gas diffusion layer 20 is P2, where P1 > P2.

[0048] The pore size of the flow field structure 10 is larger than that of the gas diffusion layer 20, forming a gradient pore structure. The flow field structure 10 can provide a larger flow field channel volume, reduce gas-liquid flow resistance, and promote the rapid and uniform distribution of reactants and products (hydrogen, oxygen, or electrolyte) throughout the flow field structure 10. The gas diffusion layer 20 can form a denser pore network, increase the capillary force of gas in the diffusion layer, limit excessive liquid permeation, and maintain the unobstructed gas transport channels. At the same time, the gradient pore structure also helps to make stress distribution more uniform, ensuring the mechanical strength of the integrated flow field diffusion layer structure 100.

[0049] In some embodiments, the thickness of the flow field structure 10 is 0.3 mm to 3 mm.

[0050] By ensuring that the thickness of the flow field structure 10 is within the aforementioned range, the gas-liquid transport efficiency and the strength of the flow field structure 10 can be guaranteed.

[0051] For example, the thickness of the flow field structure 10 can be 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm.

[0052] In some embodiments, the flow field structure 10 has a raised or recessed structure on the side near the gas diffusion layer 20. The raised or recessed structure can be at least one of the following: serpentine, dotted, mesh-like, interdigitated, porous foam-like, biomimetic, papillary, and nonwoven.

[0053] The raised or recessed structures on the surface of the flow field structure 10 can form turbulence or microchannels between the flow field structure 10 and the gas diffusion layer 20, breaking the boundary effect, accelerating gas and liquid diffusion, and improving mechanical stability.

[0054] Protrusions or depressions can be formed by laser engraving (fiber laser, ultraviolet laser, etc.) or chemical etching, electro-etching, electrodeposition, stamping, weaving, etc.

[0055] In some embodiments, the aperture of the flow field structure 10 is 10 μm-2000 μm.

[0056] By ensuring that the aperture of the flow field structure 10 is within the aforementioned range, the mechanical stability of the flow field structure 10 can be guaranteed, and the gas-liquid transport efficiency in the flow field structure 10 can be guaranteed.

[0057] For example, the aperture of the flow field structure 10 can be 10 μm, 50 μm, 100 μm, 500 μm, 1000 μm, 1500 μm or 2000 μm.

[0058] In some embodiments, the thickness of the gas diffusion layer 20 is 0.3 mm to 3 mm.

[0059] For example, the thickness of the gas diffusion layer 20 can be 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm or 3 mm.

[0060] In some embodiments, the pore size of the gas diffusion layer 20 is 0.5 μm-500 μm.

[0061] For example, the pore size of the gas diffusion layer 20 can be 0.5μm, 5μm, 10μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm or 500μm.

[0062] In some embodiments, the surface roughness Ra of the gas diffusion layer 20 is 3 μm-25 μm.

[0063] For example, the surface roughness of the gas diffusion layer 20 can be 3 μm, 5 μm, 10 μm, 15 μm, 20 μm or 25 μm.

[0064] In some embodiments, the areal density of the gas diffusion layer 20 is 50 g / m³. 2-3500g / m 2 .

[0065] For example, the areal density of the gas diffusion layer 20 can be 50 g / m². 2 100g / m 2 500g / m 2 1000g / m 2 1500g / m 2 2000g / m 2 2500g / m 2 3000g / m 2 Or 3500g / m 2 .

[0066] The thickness, pore size, surface roughness and / or areal density of the gas diffusion layer 20 are within the above range, which can ensure the structural stability of the gas diffusion layer 20, the high energy efficiency, and the transmission efficiency of gas and liquid in the gas diffusion layer 20.

[0067] In some embodiments, the thickness of the first adhesive layer 30 is 1 μm-50 μm.

[0068] The thickness of the first adhesive layer 30 is within the above range, which can enhance the interfacial bonding strength between the flow field structure 10 and the gas diffusion layer 20, ensure uniform stress distribution, reduce interfacial resistance, improve conductivity, and optimize electron conduction.

[0069] For example, the thickness of the first adhesive layer 30 can be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.

[0070] In some embodiments, the flow field structure 10 and the gas diffusion layer 20 are made of the same material, or the flow field structure 10 and the gas diffusion layer 20 are made of different materials.

[0071] Using the same material ensures that the thermal expansion properties of the flow field structure 10 and the gas diffusion layer 20 are matched, which reduces interfacial stress and simplifies the process of forming an integrated structure, thus reducing costs. Using different materials allows for functional differentiation between the flow field structure 10 and the gas diffusion layer 20, optimizing properties such as gas transport efficiency, conductivity, and mechanical strength, which helps to achieve high power density.

[0072] For example, the materials in the flow field structure 10 and the gas diffusion layer 20 can be at least one of nickel, iron, titanium, stainless steel and modified conductive polymer, and the materials of the two can be the same or different.

[0073] In some embodiments, the flow field structure 10 includes multiple flow field sublayers 11 stacked along a first direction X. The aperture of the flow field structure 10 decreases in the direction from the side away from the gas diffusion layer 20 to the side closer to the gas diffusion layer 20.

[0074] That is, in the flow field structure 10, the pore size of the flow field sub-layer 11 on the side closer to the gas diffusion layer 20 is smaller than that on the side farther from the gas diffusion layer 20, resulting in a gradient pore structure inside the flow field structure 10. The smaller pore size of the flow field sub-layer 11 on the side closer to the gas diffusion layer 20 enhances the uniformity of gas distribution, while the larger pore size of the flow field sub-layer 11 on the side farther from the gas diffusion layer 20 provides large-aperture channels, reducing liquid flow resistance. The gradient pore flow field structure 10 optimizes gas transport and liquid water management, improving the transport efficiency and service life of the flow field structure 10. The smaller pore size of the flow field sub-layer 11 on the side closer to the gas diffusion layer 20 also enhances structural support, ensuring the mechanical strength of the integrated flow field diffusion layer structure 100.

[0075] In some embodiments, the multilayer flow field sublayers 11 form an integral structure, and a second adhesive layer 12 is disposed between adjacent flow field sublayers 11. The second adhesive layer 12 includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based material.

[0076] The second bonding layer 12 can improve the bonding force between the multi-layer flow field sub-layers 11, improve the mechanical contact performance between the multi-layer flow field sub-layers 11, increase the conductive contact points, and improve the structural stability, optimize the electrical conductivity, improve the energy conversion efficiency, and extend the service life while ensuring that the flow field structure 10 forms a gradient pore structure.

[0077] In some embodiments, the thickness of the second adhesive layer 12 is 1 μm-50 μm.

[0078] The thickness of the second adhesive layer 12 is within the above range, which can enhance the interfacial bonding strength between the multilayer flow field sublayers 11, ensure uniform stress distribution, reduce interfacial resistance, improve conductivity, and optimize electron conduction.

[0079] For example, the thickness of the second adhesive layer 12 can be 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm.

[0080] In some embodiments, the flow field structure 10 is formed by laminating multiple layers of first substrate material stacked along a first direction X. The multiple layers of first substrate material are made of the same material, or the multiple layers of first substrate material are made of different materials.

[0081] By pressing together multiple layers of first matrix material stacked along the first direction X, the mechanical strength of the flow field structure 10 can be improved, and it is beneficial to achieve gradient aperture control in the flow field structure 10.

[0082] Using the same material ensures matching thermal expansion properties of each layer, reduces interfacial stress, and simplifies the process of forming a monolithic structure, thus reducing costs. Using dissimilar materials allows for functional differentiation between layers, optimizing properties such as gas transport, conductivity, and mechanical strength, which helps achieve high power density. Those skilled in the art can choose according to their specific needs.

[0083] In some embodiments, the first substrate material layer includes at least one of fiber felt, foam metal, woven mesh, stretched mesh, and perforated mesh.

[0084] Fiber felt, foam metal, woven mesh, stretched mesh, and perforated mesh are all porous structures with three-dimensional through-holes, huge specific surface area, and good mechanical strength. As the first matrix material layer, they can improve the mass transfer efficiency of the flow field structure 10 and ensure mechanical strength.

[0085] In some embodiments, the thickness of the first substrate material layer is 0.35mm-1.5mm, and the thickness of the flow field sublayer 11 is 0.3mm-1.2mm.

[0086] After pressing the multiple layers of the first matrix material, the thickness is compressed to form a multi-layer flow field sub-layer 11. By keeping the thickness of the first matrix material layer and the flow field sub-layer 11 within the above-mentioned range, the compression ratio can be guaranteed, and the mechanical strength and interface bonding performance of the flow field structure 10 can be improved.

[0087] For example, the thickness of the first substrate material layer can be 0.35 mm, 0.5 mm, 0.75 mm, 1.0 mm, 1.25 mm, or 1.5 mm. The thickness of the flow field sublayer 11 can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, or 1.2 mm.

[0088] In some embodiments, the gas diffusion layer 20 includes multiple gas diffusion sublayers 21 stacked along a first direction X, the multiple gas diffusion sublayers 21 forming an integral structure, and a third adhesive layer 22 is disposed between adjacent gas diffusion sublayers 21. The third adhesive layer 22 includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber, and carbon-based material.

[0089] The integrated structure formed by the multilayer gas diffusion sublayers 21 can improve the mechanical stability and durability of the gas diffusion layer 20. The third bonding layer 22 disposed between adjacent gas diffusion sublayers 21 can improve the interlayer bonding force, disperse stress, enhance the resistance to mechanical deformation, and can construct a continuous electronic conduction network in the gas diffusion layer 20, reducing the contact resistance between layers.

[0090] In some embodiments, the thickness of the third adhesive layer 22 is 1 μm-50 μm.

[0091] The thickness of the third adhesive layer 22 is within the above range, which can enhance the interfacial bonding strength between the multilayer gas diffusion sublayers 21, ensure uniform stress distribution, reduce interfacial resistance, improve conductivity, and optimize electron conduction.

[0092] For example, the thickness of the third adhesive layer 22 can be 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm.

[0093] In some embodiments, the pore size of the gas diffusion layer 20 decreases in the direction from the side near the flow field structure 10 to the side away from the flow field structure 10.

[0094] That is, in the gas diffusion layer 20, the pore size of the gas diffusion sublayer 21 closer to the flow field structure 10 is larger than that of the gas diffusion sublayer 21 farther away from the flow field structure, and the interior of the gas diffusion layer 20 has a gradient porosity structure. The gradient porosity gas diffusion layer 20 can optimize gas transport and liquid water management, and improve the transport efficiency and service life of the gas diffusion layer.

[0095] In some embodiments, the gas diffusion layer 20 is formed by laminating multiple layers of second substrate material stacked along a first direction X. The multiple layers of second substrate material may be of the same material, or they may be of different materials.

[0096] Similar to the flow field structure 10, the gas diffusion layer 20 is formed by pressing together multiple layers of second matrix material. By pressing together multiple layers of second matrix material stacked along the first direction X, the mechanical strength of the gas diffusion layer 20 can be improved, and it is beneficial to achieve gradient aperture control in the gas diffusion layer 20.

[0097] Using the same material ensures matching thermal expansion properties of each layer, reduces interfacial stress, and simplifies the process of forming a monolithic structure, thus reducing costs. Using dissimilar materials allows for functional differentiation between layers, optimizing properties such as gas transport, conductivity, and mechanical strength, which helps achieve high power density. Those skilled in the art can choose according to their specific needs.

[0098] In some embodiments, the second substrate material layer includes at least one of fiber felt, powdered felt, foamed metal, woven mesh, stretched mesh, perforated mesh, nonwoven fabric, woven cloth, and fiber paper.

[0099] Fiber felt, powder felt, foam metal, woven mesh, stretched mesh, perforated mesh, nonwoven fabric, woven fabric and fiber paper are all porous structures with good mechanical strength. As the second matrix material layer, they can improve the gas transmission efficiency of the gas diffusion layer 20 and ensure mechanical strength.

[0100] In some embodiments, the thickness of the second substrate material layer is 0.5 mm to 1.2 mm, and the thickness of the gas diffusion sublayer 21 is 0.3 mm to 1.0 mm.

[0101] After pressing the multiple layers of second substrate material, the thickness is compressed to form a multilayer gas diffusion sublayer 21. By keeping the thickness of the second substrate material layer and the gas diffusion sublayer 21 within the above-mentioned range, the compression ratio can be guaranteed, and the mechanical strength and interfacial bonding performance of the gas diffusion layer 20 can be improved.

[0102] For example, the thickness of the second substrate material layer can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, or 1.2 mm. The thickness of the gas diffusion sublayer 21 can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm.

[0103] In some embodiments, the integrated flow field diffusion layer structure 100 further includes a microporous layer, which is disposed on the side of the gas diffusion layer 20 away from the flow field structure 10. The thickness of the microporous layer is 10μm-40μm and the porosity is 20%-45%.

[0104] By setting a microporous layer, the distribution and transport of liquid can be optimized, while promoting gas and heat conduction, achieving efficient gas-liquid transport, which is beneficial for improving performance under high current density.

[0105] For example, the thickness of the microporous layer can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm or 40 μm, and the porosity can be 20%, 25%, 30%, 35%, 40% or 45%.

[0106] In some embodiments, the material of the microporous layer includes at least one of nickel-based metal powder, iron-based metal powder, titanium-based metal powder, and carbon-based powder.

[0107] Nickel-based, iron-based, titanium-based, and carbon-based metal powders all possess excellent electronic conductivity, which helps improve the distribution of reactants and current on the surface of the gas diffusion layer, thereby increasing reaction efficiency and extending service life. Furthermore, they can optimize interfacial contact, reduce contact resistance, and enhance performance under high current densities.

[0108] In some embodiments, the thickness of the integral flow field diffusion layer structure 100 is 0.6 mm to 6 mm.

[0109] By keeping the thickness of the integral flow field diffusion layer structure 100 within the aforementioned range, the gas transport efficiency and structural strength of the integral flow field diffusion layer structure 100 can be balanced.

[0110] For example, the thickness of the integrated flow field diffusion layer structure 100 can be 0.6mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm or 6mm.

[0111] In some embodiments, the compression ratio of the integral flow field diffusion layer structure 100 is 10%-80%.

[0112] By keeping the compressibility of the integrated flow field diffusion layer structure 100 within the above range, the interface contact between each layer can be improved, and the interface bonding force can be guaranteed.

[0113] It is understandable that the compressibility of the integrated flow field diffusion layer structure 100 refers to the ratio of the thickness after compression to the thickness before compression.

[0114] For example, the compression ratio of the integrated flow field diffusion layer structure 100 can be 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%.

[0115] In some embodiments, the areal density of the integral flow field diffusion layer structure 100 is 1000 g / m². 2 -5000g / m 2 ; By ensuring that the areal density of the integral flow field diffusion layer structure 100 is within the aforementioned range, the reaction contact area can be increased, the contact resistance reduced, and the mechanical stability enhanced.

[0116] For example, the areal density of the integral flow field diffusion layer structure 100 can be 1000 g / m². 2 2000g / m 2 3000g / m 2 4000g / m 2 Or 5000g / m 2 .

[0117] In some embodiments, the tensile strength of the integral flow field diffusion layer structure 100 is 10 MPa-200 MPa.

[0118] By ensuring that the tensile strength of the integral flow field diffusion layer structure 100 is within the aforementioned range, it is possible to resist assembly stress and vibration fatigue, thereby improving structural stability.

[0119] For example, the tensile strength of the integral flow field diffusion layer structure 100 can be 10MPa, 50MPa, 100MPa, 150MPa or 200MPa.

[0120] In some embodiments, the compressive strength of the integral flow field diffusion layer structure 100 is 3MPa-150MPa.

[0121] By ensuring that the compressive strength of the integrated flow field diffusion layer structure 100 is within the aforementioned range, it can resist deformation, guarantee the stability of the porous structure of the integrated flow field diffusion layer structure 100, and ensure gas-liquid transport efficiency.

[0122] For example, the compressive strength of the integrated flow field diffusion layer structure 100 can be 3MPa, 20MPa, 70MPa, 100MPa, 120MPa or 150MPa.

[0123] In some embodiments, the flow field structure 10, the first adhesive layer 30, and the gas diffusion layer 20 are formed into an integral structure by thermal sintering or laser welding.

[0124] Thermal sintering enables atomic diffusion between the flow field structure 10 and the gas diffusion layer 20 at high temperatures through the first bonding layer 30, forming a metallurgical bond and thus improving interfacial bonding performance. Laser welding utilizes high-energy laser melting to achieve instantaneous metallurgical bonding of the flow field structure 10, the first bonding layer 30, and the gas diffusion layer 20. Furthermore, the concentrated energy of laser welding reduces thermal stress accumulation and prevents pore collapse. Both thermal sintering and laser welding ensure effective interfacial bonding between layers. During thermal sintering or laser welding, the first bonding layer 30 reduces interfacial stress generated by thermal cycling, guaranteeing bonding strength.

[0125] According to a second aspect of this application, a method for preparing an integral flow field diffusion layer structure is also provided, comprising: Provide flow field structure 10; A first adhesive layer 30 and a gas diffusion layer 20 are sequentially disposed on one side of the flow field structure 10 in the first direction X. After pressing, a composite structure is obtained. The composite structure is formed into an integral structure by thermal sintering or laser welding to obtain an integral flow field diffusion layer structure 100.

[0126] The method for preparing the integrated flow field diffusion layer structure 100 provided in this application embodiment has all the beneficial effects of the integrated flow field diffusion layer structure 100 as described above, and will not be repeated here.

[0127] In some embodiments, the method for preparing the flow field structure 10 includes: A multilayer first substrate material layer is provided, the multilayer first substrate material layer is stacked along the first direction X, a second adhesive layer 12 is provided between adjacent first substrate material layers, roll forming, and the multilayer first substrate material layer and the second adhesive layer 12 are formed into an integral structure by hot sintering or laser welding to obtain the flow field structure 10.

[0128] By roll forming a first matrix material layered together, the structural strength and stability of the flow field structure 10 can be improved. Furthermore, using first matrix materials with different pore sizes helps to achieve a gradient aperture in the flow field structure 10. A second bonding layer 12, disposed between adjacent first matrix material layers, can improve the bonding force between the multiple first matrix material layers during subsequent thermal sintering or laser welding, improve the mechanical contact performance between layers, increase conductive contact points, and improve overall structural stability, optimize electrical conductivity, and increase energy conversion efficiency while ensuring the formation of a gradient aperture structure in the flow field structure 10. Thermal sintering technology enables atomic diffusion in the material at high temperatures, forming a metallurgical bond and effectively improving interfacial bonding performance. Laser welding technology utilizes laser melting to achieve instantaneous metallurgical bonding, concentrating energy and reducing thermal stress accumulation.

[0129] In some embodiments, a first adhesive layer 30 and a gas diffusion layer 20 are sequentially disposed on one side of the flow field structure 10 in the first direction X, including: A first adhesive layer 30 and multiple layers of second matrix material are sequentially disposed on the side with smaller aperture in the first direction X of the flow field structure 10, and a third adhesive layer 22 is disposed between adjacent second matrix material layers, and the structure is roll-formed.

[0130] The first adhesive layer 30 tightly connects the flow field structure 10 and the multilayer second matrix material layer, while the third adhesive layer 22 enables bonding between adjacent second matrix material layers, forming a stable and reliable integrated structure and reducing interfacial resistance. The arrangement of the multilayer second matrix material layer increases the strength of the gas diffusion layer 20 and improves its mechanical properties.

[0131] In some embodiments, the first adhesive layer 30, the second adhesive layer 12, and the third adhesive layer 22 may each further comprise a polymer material.

[0132] By combining polymer materials with nickel powder, titanium powder, nickel fiber, titanium fiber and carbon-based powder to form conductive adhesives, the bonding performance can be improved and the conductivity increased.

[0133] For example, the polymeric material may be at least one of polysulfone, polyetheretherketone, and anion exchange polymer.

[0134] In some embodiments, the composite structure is formed into an integral structure by hot sintering. The hot sintering temperature is 900℃-1300℃, the sintering holding time is 1h-4h, and the heating rate is 2℃ / min-10℃ / min.

[0135] By performing hot sintering under the above conditions, the interfacial bonding strength can be guaranteed, the mechanical strength of the overall structure can be guaranteed, and the hot sintering efficiency can be improved.

[0136] In some embodiments, the composite structure is formed into an integral structure by laser welding. The laser welding power is 500W-6000W, the pulse frequency is 1Hz-1000Hz, the duty cycle is 10%-90%, and the welding speed is 0.5m / min-10m / min.

[0137] By performing laser welding under the above conditions, the interfacial bonding strength can be guaranteed, the mechanical strength of the overall structure can be ensured, and the efficiency of laser welding can be improved.

[0138] According to a third aspect of this application, an electrolytic cell is also provided, comprising the integral flow field diffusion layer structure 100 as described above, and / or the integral flow field diffusion layer structure 100 prepared by the method described above.

[0139] The electrolytic cell provided in this application has all the beneficial effects of the integrated flow field diffusion layer structure 100 as described above, which will not be repeated here.

[0140] The embodiments of this application are further illustrated below with reference to specific examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. Experimental methods in the following embodiments that do not specify specific conditions are generally performed according to the conditions recommended by the manufacturer.

[0141] Example 1 (1) A first substrate material layer, a second substrate material layer, a first adhesive layer, a second adhesive layer, and a third adhesive layer are provided; wherein, the first substrate material layer is a nickel mesh, the second substrate material layer is a nickel-iron-based fiber material, and the first, second, and third adhesive layers all have an areal density of 50 g / m². 2 Nickel fiber felt with a thickness of 0.02mm; (2) Place the first substrate material layer, the second substrate material layer, the first adhesive layer, the second adhesive layer and the third adhesive layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) Nickel meshes with apertures of 250μm, 225μm, 200μm, 175μm, and 150μm (each layer of nickel mesh is 0.5mm thick) are stacked from bottom to top, with a layer of nickel fiber felt laid between adjacent nickel meshes. The meshes are then preliminarily rolled to form a flow field structure. Then, nickel-iron-based fiber materials of different weights (with the areal density controlled to be 250g / m²) are sequentially laid on the surface of the flow field structure. 2 275g / m 2 300g / m 2 325g / m 2 350g / m 2 The pore sizes are controlled by surface density and thickness, which are 30μm, 25μm, 20μm, 15μm and 10μm respectively (the thickness of each layer of nickel-iron fiber material is 0.6mm). A layer of nickel fiber felt is set on the surface of the nickel-iron fiber material and the flow field structure, as well as between adjacent nickel-iron fiber materials. It is then rolled to form a gas diffusion layer, and then sintered at 1200℃ for 3 hours in an inert atmosphere to form a composite structure. (4) A nickel-based metal powder slurry is sprayed onto one side of the gas diffusion layer in the composite structure, and then dried at 80°C and sintered at 1400°C for 30 min in an inert atmosphere to form a microporous layer, thus obtaining an integrated flow field diffusion layer structure; wherein, the nickel-based metal powder slurry, by weight percentage, includes 70% nickel powder, 20% ammonium bicarbonate, 10% polytetrafluoroethylene emulsion and 0.5% polyvinylpyrrolidone, and the nozzle diameter is 0.5 mm and the temperature is 60°C during spraying.

[0142] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 4 mm, and the areal density is 2970 g / m³. 2 The surface roughness Ra is 22.18 μm, and the planar resistivity is 1.24 mΩ·mm.

[0143] Example 2 (1) A first substrate material layer, a second substrate material layer, a first adhesive layer, a second adhesive layer, and a third adhesive layer are provided; wherein, the first substrate material layer is a nickel mesh, the second substrate material layer is a nickel-iron-based fiber material, and the first, second, and third adhesive layers all have an areal density of 50 g / m². 2 Nickel fiber felt with a thickness of 0.02mm; (2) Place the first substrate material layer, the second substrate material layer, the first adhesive layer, the second adhesive layer and the third adhesive layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) Nickel meshes with apertures of 250μm, 225μm, 200μm, 175μm, and 150μm (each layer of nickel mesh is 0.5mm thick) are stacked from bottom to top, with a layer of nickel fiber felt laid between adjacent nickel meshes. The meshes are then preliminarily rolled to form a flow field structure. Then, nickel-iron-based fiber materials of different weights are sequentially laid on the surface of the flow field structure, with the surface density controlled to be 250g / m². 2 275g / m 2 300g / m 2 325g / m 2 350g / m 2 The pore sizes are controlled by surface density and thickness, which are 30μm, 25μm, 20μm, 15μm and 10μm respectively (the thickness of each layer of nickel-iron-based fiber material is 0.6mm). A layer of nickel fiber felt is set on the surface of the nickel-iron-based fiber material and the flow field structure, as well as between adjacent nickel-iron-based fiber materials. The material is then rolled to form a gas diffusion layer. Finally, it is sintered in an inert atmosphere at a temperature of 1200℃ for 3 hours to obtain an integrated structure of the flow field diffusion layer.

[0144] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 4 mm, and the areal density is 2970 g / m³. 2 The surface roughness Ra is 20.36 μm and the planar resistivity is 4.10 mΩ·mm.

[0145] Example 3 (1) A first substrate material layer, a second substrate material layer, and a first adhesive layer are provided; wherein, the first substrate material layer is a nickel mesh, the second substrate material layer is a nickel-based fiber material, and the first adhesive layer has an areal density of 50 g / m². 2 Nickel fiber felt with a thickness of 0.02mm; (2) Place the first substrate material layer, the second substrate material layer and the first adhesive layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) A nickel mesh with a aperture of 200 μm (thickness of 1 mm) and an areal density of 800 g / m² are used. 2 Nickel-based fiber material (by controlling the areal density and thickness to 1.2 mm and adjusting the pore size to approximately 20 μm), a layer of nickel fiber felt is placed between the nickel-based fiber material and the nickel mesh, initially rolled and formed, and then hot sintered at 1200℃ for 3 hours in an inert atmosphere to obtain an integrated structure of the flow field diffusion layer.

[0146] (4) A nickel-based metal powder slurry is sprayed onto one side of the gas diffusion layer in the composite structure, and then dried at 80°C and sintered at 1400°C for 30 min in an inert atmosphere to form a microporous layer, thus obtaining an integrated flow field diffusion layer structure; wherein, the nickel-based metal powder slurry, by weight percentage, includes 70% nickel powder, 20% ammonium bicarbonate, 10% polytetrafluoroethylene emulsion and 0.5% polyvinylpyrrolidone, and the nozzle diameter is 0.5 mm and the temperature is 60°C during spraying.

[0147] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 1.8 mm, and the areal density is 2050 g / m³. 2 The surface roughness Ra is 23.29 μm and the planar resistivity is 3.65 mΩ·mm.

[0148] Example 4 (1) A first substrate material layer, a second substrate material layer, a first adhesive layer, a second adhesive layer, and a third adhesive layer are provided; wherein, the first substrate material layer is a nickel mesh, the second substrate material layer is a nickel-iron-based fiber material, and the first, second, and third adhesive layers all have an areal density of 50 g / m². 2 Nickel fiber felt with a thickness of 0.05 mm; (2) Place the first substrate material layer and the second substrate material layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) Nickel meshes with apertures of 1000μm, 775μm and 550μm (each layer of nickel mesh is 1.2mm thick) are stacked from bottom to top, and a layer of nickel fiber felt is laid between adjacent nickel meshes. The meshes are initially rolled to form a flow field structure. Then, nickel-iron-based fiber materials with different weights (apertures of 500μm, 250μm and 100μm, each layer of nickel-iron-based fiber material is 1.5mm thick) are laid on the surface of the flow field structure. The meshes are rolled again to form a gas diffusion layer. Then, the meshes are sintered at 1200℃ for 3 hours in an inert atmosphere to form a composite structure. (4) A nickel-based metal powder slurry is sprayed onto one side of the gas diffusion layer in the composite structure, and then dried at 80°C and sintered at 1400°C for 30 min in an inert atmosphere to form a microporous layer, thus obtaining an integrated flow field diffusion layer structure; wherein, the nickel-based metal powder slurry, by weight percentage, includes 70% nickel powder, 20% ammonium bicarbonate, 10% polytetrafluoroethylene emulsion and 0.5% polyvinylpyrrolidone, and the nozzle diameter is 0.5 mm and the temperature is 60°C during spraying.

[0149] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 6 mm, and the areal density is 3500 g / m³. 2The surface roughness Ra is 24.91 μm, and the planar resistivity is 4.92 mΩ·mm.

[0150] Example 5 (1) A first substrate material layer, a second substrate material layer, a first adhesive layer, a second adhesive layer, and a third adhesive layer are provided; wherein, the first substrate material layer is a nickel mesh, the second substrate material layer is a nickel-iron-based fiber material, and the first, second, and third adhesive layers all have an areal density of 50 g / m². 2 Nickel fiber felt with a thickness of 0.001 mm; (2) Place the first substrate material layer and the second substrate material layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) A nickel mesh with a pore size of 10 μm (thickness of 0.35 mm) and a nickel-iron fiber material with a pore size of 0.5 μm (thickness of 0.5 mm) are initially rolled and then sintered in an inert atmosphere at a temperature of 1200℃ for 3 hours to form a composite structure. (4) A nickel-based metal powder slurry is sprayed onto one side of the gas diffusion layer in the composite structure, and then dried at 80°C and sintered at 1400°C for 30 min in an inert atmosphere to form a microporous layer, thus obtaining an integrated flow field diffusion layer structure; wherein, the nickel-based metal powder slurry, by weight percentage, includes 70% nickel powder, 20% ammonium bicarbonate, 10% polytetrafluoroethylene emulsion and 0.5% polyvinylpyrrolidone, and the nozzle diameter is 0.5 mm and the temperature is 60°C during spraying.

[0151] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 0.6 mm, and the areal density is 1850 g / m³. 2 The surface roughness Ra is 21.23 μm, and the planar resistivity is 1.01 mΩ·mm.

[0152] Comparative Example 1 (1) The flow field structure is a nickel mesh with a thickness of 1 mm and a pore size of 250 μm; (2) The gas diffusion layer has a thickness of 0.8 mm and an areal density of 1000 g / m³. 2 Nickel felt with a pore size of 50 μm, a surface roughness of 20.62 μm, and a planar resistivity of 5.84 mΩ·mm; (3) The flow field structure and the gas diffusion layer structure are stacked and assembled into the electrolytic cell for testing.

[0153] Comparative Example 2 (1) Provide a first substrate material layer and a second substrate material layer; wherein, the first substrate material layer is a nickel mesh and the second substrate material layer is a nickel-iron-based fiber material; (2) Place the first substrate material layer and the second substrate material layer in ethanol and ultrasonically clean for 15 minutes to remove surface organic contaminants. Then place them in dilute hydrochloric acid and ultrasonically clean for 15 minutes to remove other contaminants. Then rinse with deionized water and blow dry with nitrogen. (3) Nickel meshes with apertures of 250μm, 225μm, 200μm, 175μm, and 150μm (each layer of nickel mesh is 0.5mm thick) are stacked from bottom to top and preliminarily rolled to form a flow field structure. Then, nickel-iron-based fiber materials with different basis weights (area densities of 250g / m²) are sequentially laid on the surface of the flow field structure. 2 275g / m 2 300g / m 2 325g / m 2 350g / m 2 By controlling the areal density and thickness to adjust the pore size to 30μm, 25μm, 20μm, 15μm, and 10μm (the thickness of each layer of nickel-iron-based fiber material is 0.6mm), it is rolled again to form a gas diffusion layer, and then sintered in an inert atmosphere at a temperature of 1200℃ for 3 hours to form a composite structure. (4) A nickel-based metal powder slurry is sprayed onto one side of the gas diffusion layer in the composite structure, and then dried at 80°C and sintered at 1400°C for 30 min in an inert atmosphere to form a microporous layer, thus obtaining an integrated flow field diffusion layer structure; wherein, the nickel-based metal powder slurry, by weight percentage, includes 70% nickel powder, 20% ammonium bicarbonate, 10% polytetrafluoroethylene emulsion and 0.5% polyvinylpyrrolidone, and the nozzle diameter is 0.5 mm and the temperature is 60°C during spraying.

[0154] In this embodiment, the thickness of the integrated flow field diffusion layer structure is 4 mm, and the areal density is 2650 g / m³. 2 The surface roughness Ra is 22.32 μm, and the planar resistivity is 2.23 mΩ·mm.

[0155] The integrated flow field diffusion layer structures in Examples 1-5 and Comparative Example 2, as well as the composite structure of flow field structure and gas diffusion layer in Comparative Example 1, were placed on a test bench to test ohmic impedance and water electrolysis performance.

[0156] The ohmic impedance test method is as follows: Using an electrochemical workstation, the working electrode line WE and the working sensing electrode line WS are connected to the cathode side plate, and the reference electrode line RE and the auxiliary electrode line are connected to the anode side plate. The constant voltage AC impedance of the test object is measured at open circuit potential, with a high frequency of 10000Hz, a low frequency of 1Hz, and an amplitude of 10mV. After fitting the test results, the ohmic impedance value is recorded. The test method for water electrolysis performance is as follows: Using an electrochemical workstation, the working electrode line WE and the working sensing electrode line WS are connected to the cathode side plate, and the reference electrode line RE and the auxiliary electrode line are connected to the anode side plate. A constant current test method is used, within the range of 0~2A / cm. 2 At a given current density, 24 current steps were set up, with each step tested for 10 seconds. One voltage value was recorded per second, and the average voltage across each current step was recorded. The test results are shown in Table 1 and... Figure 2 As shown.

[0157] Table 1. Comparison of Ohmic Impedance and Water Electrolysis Performance Test Results in Different Embodiments and Comparative Examples

[0158] From Table 1 and Figure 2 As can be seen, compared to the separate flow field and gas diffusion layer configuration in Comparative Example 1, Embodiments 1-5 of this application significantly reduce ohmic impedance through an integrated flow field diffusion layer structure, exhibiting lower resistance and superior conductivity. Furthermore, the CP voltage is superior to that of Comparative Example 1 at different current densities, thus improving the energy efficiency of the electrolyzer. Compared to the form without a bonding layer in Comparative Example 2, the integrated flow field diffusion layer structure in Embodiments 1-5 of this application, through the addition of a first bonding layer, a second bonding layer, and a third bonding layer, reduces the contact resistance and ohmic loss between the flow field structure and the gas diffusion layer, thereby significantly reducing ohmic impedance, improving dynamic response performance, and ensuring energy efficiency.

[0159] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An integrated structure (100) for a flow field diffusion layer, characterized in that, include: Flow field structure (10); A gas diffusion layer (20) and the flow field structure (10) are stacked along a first direction; A first adhesive layer (30) is disposed between the flow field structure (10) and the gas diffusion layer (20). The material of the first adhesive layer (30) includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber and carbon-based material. The flow field structure (10), the first adhesive layer (30), and the gas diffusion layer (20) form an integral structure.

2. The integrated flow field diffusion layer structure (100) according to claim 1, characterized in that, The pore size of the flow field structure (10) is P1, and the pore size of the gas diffusion layer (20) is P2, where P1 > P2.

3. The integrated flow field diffusion layer structure (100) according to claim 2, characterized in that, The thickness of the flow field structure (10) is 0.3mm-3mm; And / or, the aperture of the flow field structure (10) is 10μm-2000μm.

4. The integrated flow field diffusion layer structure (100) according to claim 2, characterized in that, The thickness of the gas diffusion layer (20) is 0.3 mm to 3 mm; And / or, the pore size of the gas diffusion layer (20) is 0.5 μm-500 μm; And / or, the surface roughness Ra of the gas diffusion layer (20) is 3μm-25μm; And / or, the areal density of the gas diffusion layer (20) is 50 g / m³. 2 -3500g / m 2 .

5. The integrated flow field diffusion layer structure (100) according to claim 1, characterized in that, The thickness of the first adhesive layer (30) is 1μm-50μm.

6. The integrated flow field diffusion layer structure (100) according to claim 1, characterized in that, The flow field structure (10) and the gas diffusion layer (20) are made of the same material, or the flow field structure (10) and the gas diffusion layer (20) are made of different materials.

7. The integrated flow field diffusion layer structure (100) according to claim 1, characterized in that, The flow field structure (10) includes multiple flow field sub-layers (11) stacked along the first direction; The aperture of the flow field structure (10) decreases in the direction from the side away from the gas diffusion layer (20) to the side closer to the gas diffusion layer (20).

8. The integrated flow field diffusion layer structure (100) according to claim 7, characterized in that, The multiple flow field sub-layers (11) form an integral structure, and a second adhesive layer (12) is provided between adjacent flow field sub-layers (11); The second adhesive layer (12) includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber and carbon-based material.

9. The integrated flow field diffusion layer structure (100) according to claim 1, characterized in that, The gas diffusion layer (20) includes multiple gas diffusion sublayers (21) stacked along the first direction, the multiple gas diffusion sublayers (21) forming an integral structure, and a third adhesive layer (22) is provided between adjacent gas diffusion sublayers (21); The third adhesive layer (22) includes at least one of nickel powder, titanium powder, nickel fiber, titanium fiber and carbon-based material.

10. The integrated flow field diffusion layer structure (100) according to any one of claims 1-9, characterized in that, The integrated flow field diffusion layer structure (100) further includes a microporous layer, which is disposed on the side of the gas diffusion layer (20) away from the flow field structure (10); The thickness of the microporous layer is 10μm-40μm, and the porosity is 20%-45%.

11. The integrated flow field diffusion layer structure (100) according to claim 10, characterized in that, The material of the microporous layer includes at least one of nickel-based metal powder, iron-based metal powder, titanium-based metal powder, and carbon-based powder.

12. The integrated flow field diffusion layer structure (100) according to any one of claims 1-9, characterized in that, The thickness of the integrated flow field diffusion layer structure (100) is 0.6mm-6mm; And / or, the compressibility of the integral flow field diffusion layer structure (100) is 10%-80%; And / or, the areal density of the integral flow field diffusion layer structure (100) is 1000 g / m³. 2 -5000g / m 2 ; And / or, the tensile strength of the integral structure (100) of the flow field diffusion layer is 10MPa-200MPa; And / or, the compressive strength of the integral structure (100) of the flow field diffusion layer is 3MPa-150MPa.

13. A method for preparing an integrated flow field diffusion layer structure, characterized in that, include: Provide flow field structure (10); A first adhesive layer (30) and a gas diffusion layer (20) are sequentially disposed on one side of the flow field structure (10) in the first direction. After pressing, a composite structure is obtained. The composite structure is formed into an integral structure by thermal sintering or laser welding to obtain the integral structure of the flow field diffusion layer (100).

14. The method for preparing the integrated flow field diffusion layer structure according to claim 13, characterized in that, The method for preparing the flow field structure (10) includes: A multilayer first substrate material layer is provided, the multilayer first substrate material layer is stacked along a first direction, a second adhesive layer (12) is provided between adjacent first substrate material layers, roll forming, and the multilayer first substrate material layer and the second adhesive layer (12) are formed into an integral structure by hot sintering or laser welding to obtain the flow field structure (10).

15. The method for preparing the integrated flow field diffusion layer structure according to claim 13, characterized in that, The first adhesive layer (30) and the gas diffusion layer (20) are sequentially disposed on one side of the flow field structure (10) in the first direction, including: The first adhesive layer (30) and multiple layers of second matrix material are sequentially disposed on the side with smaller aperture in the first direction of the flow field structure (10), and a third adhesive layer (22) is disposed between adjacent second matrix material layers, and the structure is roll-formed.

16. An electrolytic cell, characterized in that, Includes the integrated flow field diffusion layer structure (100) as described in any one of claims 1-12, and / or the integrated flow field diffusion layer structure (100) prepared by the method described in any one of claims 13-15.

Images