Gas diffusion layer and membrane electrode assembly

Abstract

The utility model relates to the technical field of water electrolysis hydrogen production, and provides a gas diffusion layer and a membrane electrode assembly. The gas diffusion layer comprises a supporting part and an extending part, and the supporting part is formed by folding a zigzag porous nickel net. And the extension part is used for connecting a power supply. The pore size of the porous nickel net is 30-60 meshes, and the thickness of the porous nickel net is 200-350 microns. And the thickness of the supporting part is 40 to 60mm. And the area of the supporting part is 20-40cm < 2 >. The membrane electrode assembly comprises an anode gas diffusion layer, a cathode gas diffusion layer, an anode catalyst layer, an anion exchange membrane and a cathode catalyst layer. According to the utility model, the corrosion resistance and chemical structure stability of the gas diffusion layer can be improved, the stability of the membrane electrode assembly is further improved, the diffusion layer replaces a polar plate, the assembly process of the AEM electrolytic bath is simplified, and the production cost is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen production by electrolysis of water, in particular to a gas diffusion layer and a membrane electrode assembly. Background Art

[0002] In recent years, due to global energy consumption and environmental issues, clean energy and renewable energy have attracted widespread attention. Under the low-carbon goal, hydrogen energy has attracted increasing attention due to its high efficiency, cleanliness and sustainability. The production of green hydrogen using renewable energy and water electrolysis technology has been recognized as one of the most promising technological approaches for large-scale conversion of renewable energy. Among the technologies for hydrogen production by water electrolysis, anion exchange membrane (AEM) water electrolysis has the advantages of zero carbon emissions, compact structure, small footprint, high current density and high hydrogen purity. It is currently one of the most influential and practical green hydrogen production methods.

[0003] The components of a single anion exchange membrane water electrolysis unit mainly include membrane electrode, gas diffusion layer, electrode plate, end plate, sealing material, etc. Among them, the gas diffusion layer contacts the catalyst layer and electrode plate, supports the membrane electrode, and affects the transmission of electrons, reactants / products, and heat.

[0004] The decline in hydrogen production efficiency from water electrolysis in AEM electrolyzers is primarily due to slow reaction kinetics, ohmic resistance, and mass transfer resistance. The increase in mass transfer resistance primarily occurs during the water electrolysis reaction. When operating an AEM electrolyzer at high current density, the reaction products, O₂ / H₂, cannot be promptly discharged and accumulate in the voids of the gas diffusion layer. This increases the mass transfer resistance, reduces the AEM electrolyzer's energy efficiency, and increases hydrogen production costs. Therefore, it is necessary to design a multifunctional gas diffusion layer and a membrane electrode assembly incorporating such a gas diffusion layer.

[0005] The gas diffusion layer of the prior art is co-sputtered onto carbon paper (gas diffusion layer) using oblique-angle magnetron sputtering, with Ni and axially wrapped Fe strips as targets. By adjusting the number of Fe strips, a series of gas diffusion electrodes with different Ni / Fe ratios are obtained. However, this carbon-based gas diffusion layer is prone to rapid corrosion and degradation in an alkaline environment and under anodizing potential, which indirectly makes it difficult for the NiFe-based catalytic layer to exert its own activity, thereby causing the overall performance of the membrane electrode (MEA) to decline and reducing the stability of the electrolyzer system. In addition, although carbon materials (carbon paper / carbon fiber) have the advantages of high conductivity and high surface area, their high cost has hindered the commercialization of AEM electrolyzers. Utility Model Content

[0006] The utility model mainly solves the technical problem that the carbon-based gas diffusion layer of the existing technology is prone to rapid corrosion and degradation in an alkaline environment and under an anodic oxidation potential during long-term testing of the electrolyzer, causing the overall performance of the membrane electrode to decline and reducing the stability of the electrolyzer system. A gas diffusion layer and membrane electrode assembly are proposed to improve the corrosion resistance and chemical structure stability of the gas diffusion layer, thereby improving the stability of the membrane electrode assembly, simplifying the AEM electrolyzer assembly process, and saving production costs.

[0007] The utility model provides a gas diffusion layer, wherein the gas diffusion layer adopts a porous nickel mesh;

[0008] The gas diffusion layer comprises: a supporting portion and an extending portion;

[0009] The support portion is formed by folding a zigzag porous nickel mesh.

[0010] Preferably, the extension portion is used to connect to a power source.

[0011] Preferably, the porous nickel mesh has a pore size of 30-60 mesh and a thickness of 200-350 μm.

[0012] Preferably, the thickness of the support portion is 40-60 mm, and the area of ​​the support portion is 20-40 cm 2 .

[0013] Correspondingly, the present invention also provides a membrane electrode assembly, comprising: an anode gas diffusion layer, a cathode gas diffusion layer, an anode catalyst layer, an anion exchange membrane and a cathode catalyst layer;

[0014] An anode catalyst layer is provided on one side of the anion exchange membrane, and a cathode catalyst layer is provided on the other side;

[0015] The anion exchange membrane, the anode catalyst layer and the cathode catalyst layer are arranged between the anode gas diffusion layer and the cathode gas diffusion layer;

[0016] The anode gas diffusion layer and the cathode gas diffusion layer both adopt the gas diffusion layer provided by any embodiment of the present utility model.

[0017] The gas diffusion layer and membrane electrode assembly provided by the present invention have the following advantages compared with the prior art:

[0018] 1. Using a metal substrate (porous nickel mesh) instead of carbon material can improve the corrosion resistance and chemical structure stability of the gas diffusion layer (GDL).

[0019] 2. The porous nickel mesh used in the present invention serves as a gas diffusion layer (GDL) and can also replace the electrode plate to conduct electrons. This multifunctional gas diffusion layer can reduce the contact resistance between materials, simplify the electrolytic cell assembly process, and save production costs.

[0020] 3. The ordered structure of the gas diffusion layer achieves uniform arrangement of pores, effectively improves conductivity, and promotes the flow and uniform distribution of liquid in the gas diffusion layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic structural diagram of the porous nickel mesh provided by the present invention;

[0022] Figure 2 This is a schematic structural diagram of the gas diffusion layer provided by the present utility model;

[0023] Figure 3 It is a structural schematic diagram of the membrane electrode assembly provided by the utility model. DETAILED DESCRIPTION

[0024] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, rather than all of its contents.

[0025] Example 1

[0026] like Figure 1-2 As shown, an embodiment of the present invention provides a gas diffusion layer, wherein the gas diffusion layer adopts a porous nickel mesh; the porous nickel mesh has a pore size of 30-60 meshes and a thickness of 200-350 μm.

[0027] The gas diffusion layer includes: a support portion 101 and an extension portion 102;

[0028] The support portion 101 is formed by folding a zigzag porous nickel mesh. The thickness of the support portion 101 is 40-60 mm, and the area of ​​the support portion 101 is 20-40 cm 2 .

[0029] The extension portion 102 is a portion of the porous nickel mesh extending from the electrolytic cell. The extension portion 102 is used to connect to a power source, conduct electrons, simplify the electrolytic cell assembly process, and reduce contact resistance.

[0030] In this embodiment, the gas diffusion layer can be made by die stamping in metal processing technology. A porous nickel mesh is placed on a metal mold with a serrated shape, and the porous nickel mesh is processed into a serrated shape. Then, a part of one side is folded to form a support portion 101, and the unfolded part forms an extension portion 102.

[0031] The gas diffusion layer made of porous nickel mesh has an ordered structure that achieves uniform pore arrangement, promoting the flow and uniform distribution of liquid within the gas diffusion layer. The gas diffusion layer provided by this utility model serves as both a cathode gas diffusion layer and an anode gas diffusion layer, and can also replace electrode plates. This multifunctional gas diffusion layer can reduce contact resistance between materials, simplify electrolytic cell assembly processes, and save production costs.

[0032] Example 2

[0033] like Figure 3 As shown, a membrane electrode assembly provided by an embodiment of the present invention includes: an anode gas diffusion layer 1, a cathode gas diffusion layer 2, an anode catalyst layer 3, an anion exchange membrane 4 and a cathode catalyst layer 5.

[0034] An anode catalyst layer 3 is provided on one side of the anion exchange membrane 4 , and a cathode catalyst layer 5 is provided on the other side.

[0035] The anion exchange membrane 4 , the anode catalyst layer 3 and the cathode catalyst layer 5 are arranged between the anode gas diffusion layer 1 and the cathode gas diffusion layer 2 .

[0036] The anode gas diffusion layer 1 and cathode gas diffusion layer 2 both utilize the gas diffusion layer provided by any embodiment of the present invention. The anode gas diffusion layer 1 and cathode gas diffusion layer 2, made of porous nickel mesh, support the membrane electrode. The gas diffusion layer supports the membrane electrode, efficiently transports reactants to the catalyst layer, and facilitates gas discharge toward the flow channel outlet.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications to the technical solutions described in the above embodiments, or equivalent replacement of some or all of the technical features therein, do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas diffusion layer, characterized in that: The gas diffusion layer adopts a porous nickel mesh; The gas diffusion layer comprises: a supporting portion (101) and an extending portion (102); The support portion (101) is formed by folding a zigzag porous nickel mesh.

2. The gas diffusion layer according to claim 1, characterized in that The extension portion (102) is used to connect to a power source.

3. The gas diffusion layer according to claim 1, characterized in that The porous nickel mesh has a pore size of 30-60 meshes and a thickness of 200-350 μm.

4. The gas diffusion layer according to claim 1, wherein The support portion (101) has a thickness of 40-60 mm and an area of ​​20-40 cm 2 .

5. A membrane electrode assembly, characterized in that: include: An anode gas diffusion layer (1), a cathode gas diffusion layer (2), an anode catalyst layer (3), an anion exchange membrane (4) and a cathode catalyst layer (5); An anode catalyst layer (3) is provided on one side of the anion exchange membrane (4), and a cathode catalyst layer (5) is provided on the other side; The anion exchange membrane (4), the anode catalyst layer (3) and the cathode catalyst layer (5) are arranged between the anode gas diffusion layer (1) and the cathode gas diffusion layer (2); The anode gas diffusion layer (1) and the cathode gas diffusion layer (2) both adopt the gas diffusion layer according to any one of claims 1 to 4.

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