High-stability water electrolysis hydrogen production membrane electrode with interface optimization structure

Abstract

The utility model relates to the technical field of porous electrodes for hydrogen production by electrolysis of water, and particularly discloses a high-stability membrane electrode for hydrogen production by electrolysis of water with an interface optimization structure, elastic buffer layers are respectively arranged in an anode gas diffusion layer and a cathode gas diffusion layer, frames are additionally arranged on two sides of a CCM, and gaps are reserved on the two sides of the CCM. Through the design of an asymmetric frame and an elastic buffer layer, the damage of a rigid gas diffusion layer (GDL) to a catalyst layer CCM under assembly pressure, cathode high pressure and CCM swelling stress is weakened, and an elastic layer absorbs pressure energy to slow down interface extrusion; the pore gradient GDL structure improves gas discharge and reduces mass transfer resistance energy loss, and the elastic layer maintains tight contact between the GDL and the CCM so as to reduce ohmic loss. Mechanical stability is improved, CCM structure damage is reduced, and the running performance stability of electrolyzed water and the stability of hydrogen in oxygen are guaranteed; the asymmetric frame, the buffer layer and the thickness-adjustable elastic structure cooperatively adapt to pressure fluctuation and stress change, and adapt to technical scenes of renewable energy coupling hydrogen production, off-grid high-pressure hydrogen storage and the like.

Description

Technical Field

[0001] This utility model relates to the field of porous electrode technology for hydrogen production by water electrolysis, and more specifically, to a highly stable membrane electrode for hydrogen production by water electrolysis with an optimized interface structure. Background Technology

[0002] As a crucial pathway for clean energy conversion, the performance and stability of the membrane electrode assembly (MEA), a core component of water electrolysis for hydrogen production, directly determine the system's efficiency and lifespan. Direct storage of high-pressure hydrogen can meet the filling requirements of high-pressure hydrogen storage cylinders, eliminating the need for multi-stage compressor units, simplifying the water electrolysis system structure, and improving system efficiency. Therefore, increasing the operating pressure on the cathode side has become an important development direction for electrolyzers. However, high pressure on the cathode side alone will face severe problems of compressive stress imbalance and hydrogen safety: because the gas transport layer and its adjacent flow field are rigid structures, the pressure generated by the high pressure on the cathode side will be transmitted to the interface between the anode catalyst layer and the anode gas transport layer through the flexible catalyst coating membrane (CCM). The traditional symmetrical structure leads to the anode side bearing pressure exceeding the design limit, causing damage to the anode catalyst layer structure, and even membrane structure damage and CCM deformation, resulting in reduced water electrolysis performance and increased hydrogen content in oxygen, which is crucial for operational safety. Furthermore, during operation, the thickness of the CCM will gradually increase, further exacerbating CCM compression deformation, leading to performance degradation and increased hydrogen content in oxygen. Utility Model Content

[0003] The present invention aims to overcome at least one deficiency of the prior art and provide a highly stable electrolytic hydrogen production membrane electrode with an optimized interface structure, thereby improving the mechanical stability of the membrane electrode, slowing down CCM deformation, and enhancing the performance stability and hydrogen stability in oxygen during the operation of water electrolysis.

[0004] The technical solution adopted by this utility model is to provide a highly stable electrolytic water electrolysis hydrogen production membrane electrode with an interface-optimized structure, comprising an anode gas diffusion layer, an anode frame, a catalyst coating membrane (CCM), a cathode frame, and a cathode gas diffusion layer stacked sequentially. The anode gas diffusion layer includes an anode diffusion layer base layer and an anode buffer layer, with the anode buffer layer located on the side close to the catalyst coating membrane. The cathode gas diffusion layer includes a cathode diffusion layer base layer and a cathode buffer layer, with the cathode buffer layer located on the side close to the catalyst coating membrane. The anode gas diffusion layer also includes an anode elastic buffer layer located between the anode diffusion layer base layer and the anode buffer layer. The cathode gas diffusion layer also includes a cathode elastic buffer layer located between the cathode diffusion layer base layer and the cathode buffer layer.

[0005] In the process of hydrogen production through water electrolysis, the stress generated by cathode-side pressure and CCM swelling acts on the gas diffusion layer, especially the anode gas diffusion layer. The rigid structure of the existing gas diffusion layer is a key factor leading to its compression and damage at the CCM interface. To cope with these forces, an anode elastic buffer layer is added between the anode diffusion layer base layer and the anode buffer layer. When the cathode is operating at high pressure, the anode elastic buffer layer can absorb some of the cathode-side pressure and CCM swelling stress, reducing the compression deformation of the anode gas diffusion layer at the CCM interface. When the cathode is operating at normal pressure or reduced pressure, the elastic buffer layer can promote close contact between the anode buffer layer and the CCM interface, thereby ensuring the performance stability of water electrolysis.

[0006] Furthermore, the material of the anode elastic buffer layer is one of the following: metal-based elastic porous material, conductive polymer composite material, and ceramic-metal composite porous material.

[0007] Furthermore, the thickness of the anode elastic buffer layer is 0.005~1 mm.

[0008] Furthermore, the material of the cathode elastic buffer layer is one of carbon-based elastic porous materials, metal-based elastic porous materials, conductive polymer composite materials, and ceramic-metal composite porous materials.

[0009] Furthermore, the thickness of the cathode elastic buffer layer is 0.005~1 mm.

[0010] Furthermore, a first gap is reserved in the middle of the anode frame, located between the anode gas diffusion layer and the catalyst coating film; a second gap is reserved in the middle of the cathode frame, located between the cathode gas diffusion layer and the catalyst coating film. Because the cathode side pressure and CCM swelling stress cause both the cathode gas diffusion layer and the CCM to deform towards the anode gas diffusion layer, the aforementioned first and second gaps are provided to prevent excessive contact after deformation during high-pressure operation of the cathode, helping to reduce mechanical damage caused by deformation and compression, thereby ensuring the performance stability of water electrolysis. In addition, as mentioned above, when the cathode operates at normal pressure or reduced pressure, the elastic buffer layer can push the anode buffer layer and the anode catalyst layer interface into close contact, thereby ensuring the performance stability of water electrolysis.

[0011] Furthermore, the anode buffer layer has a multi-layer structure, with porosity or pore size increasing progressively from the side closest to the CCM to the side furthest from the CCM. The porosity of the first buffer layer is 10%-70%; the porosity of the anode diffusion layer substrate is 20-90%. In the anode gas diffusion layer, the anode diffusion layer substrate provides mechanical support; the anode buffer layer is designed with a smoother surface structure and is placed at the interface in contact with the anode catalyst layer to minimize the mechanical compressive effects of cathode-side pressure and CCM swelling on the anode. To optimize the interface structure, the anode buffer layer is designed with a multi-layered gradient pore size or porosity distribution structure. The first buffer layer, closest to the CCM, generally has a smaller porosity or pore size to ensure surface smoothness; considering gas transport requirements, a second buffer layer with higher porosity or larger pore size can be added, as well as a third buffer layer with increasing porosity or pore size, and so on.

[0012] Furthermore, the cathode buffer layer has a multi-layer structure, with porosity or pore size gradually increasing from the side closest to the CCM to the side furthest from the CCM. The first buffer layer in contact with the cathode catalyst layer has a smoother surface, which can reduce the squeezing damage to the cathode catalyst layer by the cathode gas diffusion layer under assembly forces. The gradient design with gradually increasing porosity from the cathode catalyst layer to the cathode gas diffusion layer substrate also helps to facilitate rapid hydrogen discharge and enhance mass transfer. The design of the elastic buffer layer also allows the membrane electrode to be adapted to operation under different operating pressures, ensuring contact between the cathode gas diffusion layer and the CCM.

[0013] The cathode gas diffusion layer can be an integral structure or a combination of a base layer and various buffer layers. Further, the materials of the anode diffusion layer base layer and the cathode diffusion layer base layer are one of titanium felt, sintered titanium plate, and porous titanium plate.

[0014] Furthermore, the materials of the anode buffer layer and the cathode buffer layer are at least one of the following: titanium felt, sintered titanium plate, porous titanium plate, titanium fiber sintered material, titanium powder sintered material, Ir / Ta alloy material, Pt / TiN nanowire material, fluorine-doped tin oxide (FTO), TiC titanium-based material, noble metal modified material, and non-noble metal corrosion-resistant material.

[0015] Furthermore, the root mean square deviation (Sq) of the surface roughness of the anode buffer layer and the cathode buffer layer is 0.1~50µm. Appropriate roughness can increase the specific surface area of ​​the electrode, provide more reaction sites, improve electrochemical activity, promote electrolyte ion diffusion, reduce ion transport resistance, and enhance membrane electrode performance.

[0016] Furthermore, the cathode frame and anode frame are divided into a frame substrate and an adhesive, with the adhesive located on the side close to the catalyst coating film; the frame substrate material is one of PEN, PPS, and PTFE; one side of the frame substrate is covered with adhesive for bonding to the CCM, proton exchange membrane, or a frame with adhesive on the other side; the adhesive is at least one of epoxy resin, polyolefin material, acrylate, and acrylic.

[0017] Further, the cathode frame thickness is 0.01~0.15 mm. The thickness of the cathode frame does not exceed the thickness of the anode frame. The ratio of the cathode frame thickness to the catalyst coating film thickness is 0.05~10. The frame thickness of the cathode and anode is closely related to CCM swelling and cathode back pressure: a suitable frame thickness can provide sufficient space for CCM swelling during operation, preventing excessive compression of the cathode and anode catalyst layers by the gas diffusion layer; since the high pressure on the cathode side will press the CCM towards the anode gas diffusion layer, in order to better suit the high-pressure operation of the cathode, it is preferable that the anode and cathode frames be designed as an asymmetrical structure, that is, the thickness of the anode frame is greater than the thickness of the cathode frame. This can reserve more space on the anode side, thereby reducing the compression deformation of the CCM by the anode gas diffusion layer. However, an excessively thick anode frame will cause excessive tension on the CCM, resulting in membrane damage, and will also affect the contact between the gas diffusion layer and the CCM, thus reducing the water electrolysis performance.

[0018] Preferably, the thickness ratio of the anode frame to the cathode frame is 1-10.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] (1) Improved mechanical stability: The asymmetric frame design combined with the gas diffusion layer buffer layer design can reduce the damage of the rigid gas diffusion layer to the CCM structure under the action of assembly pressure, cathode high pressure and CCM swelling stress; the elastic buffer layer can help the CCM absorb some pressure energy and reduce the squeezing effect of the gas diffusion layer and CCM interface.

[0021] (2) Optimization of electrochemical performance: The gas diffusion layer structure design with pore gradient can improve gas discharge and reduce energy loss caused by mass transfer resistance; the elastic buffer layer can ensure close contact between the gas diffusion layer and CCM at all times and reduce ohmic loss.

[0022] (3) Improved durability and safety: Improved mechanical stability means less damage to the CCM structure, which helps to improve the performance stability and hydrogen stability in oxygen during the operation of water electrolysis;

[0023] (4) Wide operating condition adaptability: The asymmetric frame design combined with the gas diffusion layer buffer layer design and the elastic buffer layer structure with thickness adjustment function can adapt well to stress changes under pressure fluctuation conditions. It is particularly suitable for cutting-edge scenarios such as renewable energy coupled hydrogen production and off-grid high-pressure hydrogen storage, and has significant technological advancement and market competitiveness. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the membrane electrode structure of this utility model.

[0025] Figure 2 This is a comparison diagram of hydrogen in oxygen under voltage fluctuation conditions between Embodiment 1 and Comparative Example 1 of this utility model.

[0026] Figure 3 This is a comparison diagram of hydrogen in oxygen under voltage fluctuation conditions between Embodiment 1 and Comparative Example 2 of this utility model.

[0027] Figure 4 This is a comparison diagram of hydrogen in oxygen under voltage fluctuation conditions between Embodiment 1 and Comparative Example 3 of this utility model.

[0028] Figure 5 This is a comparison diagram of current density under voltage fluctuation conditions in Embodiment 1 of this utility model.

[0029] Figure 6 This is a comparison chart of the current density under voltage fluctuation conditions for Comparative Example 2 of this utility model.

[0030] Figure 7 This is a comparison chart of the current density under voltage fluctuation conditions for Comparative Example 3 of this utility model.

[0031] In the figure: 1. Anode gas diffusion layer base layer; 2. Anode gas diffusion layer elastic buffer layer; 3. Anode gas diffusion layer buffer layer; 4. Anode frame substrate; 5. Anode frame adhesive; 6. Anode catalyst layer; 7. Anode hydrogen removal layer; 8. Proton exchange membrane; 9. Cathode catalyst layer; 10. Cathode frame adhesive; 11. Cathode frame substrate; 12. Cathode gas diffusion layer buffer layer; 13. Cathode gas diffusion layer elastic buffer layer; 14. Cathode gas diffusion layer base layer. Detailed Implementation

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] The present invention will now be further described with reference to specific examples. The following embodiments are only for explaining the present invention and do not constitute a limitation thereof. If the specific experimental conditions are not specified in the embodiments, they shall be understood according to conventional conditions or conditions recommended by the reagent company; unless otherwise specified, the reagents, consumables, etc. used in the following embodiments can be obtained from commercial sources.

[0035] Example 1

[0036] like Figure 1 As shown, the membrane electrode structure, from top to bottom, consists of: anode gas diffusion layer substrate 1, anode gas diffusion layer elastic buffer layer 2, anode gas diffusion layer buffer layer 3, anode frame substrate 4, anode frame adhesive 5, anode catalyst layer 6, anode hydrogen removal layer 7, proton exchange membrane 8, cathode catalyst layer 9, cathode frame adhesive 10, cathode frame substrate 11, cathode gas diffusion layer buffer layer 12, cathode gas diffusion layer elastic buffer layer 13, and cathode gas diffusion layer substrate 14. The anode catalyst layer 6, anode hydrogen removal layer 7, proton exchange membrane 8, and cathode catalyst layer 9 constitute the cathode membrane diffusion layer (CCM). The cathode and anode gas diffusion layers are divided into a substrate layer and a buffer layer, with the substrate layer primarily providing mechanical support. In this embodiment, both the cathode and anode gas diffusion layers employ a buffer layer structure design. This buffer layer has a smoother surface structure than the substrate layer, used to minimize the mechanical compression effects of assembly pressure, cathode side pressure, and CCM swelling on the cathode and anode. The anode gas diffusion layer base layer 1 is made of titanium felt with a thickness of 0.3 mm and a porosity of 70%. The anode gas diffusion layer buffer layer 3 is made of sintered titanium powder with a thickness of 0.08 mm and a porosity of 30%. The cathode gas diffusion layer base layer 14 is made of carbon paper with a thickness of 0.2 mm and a porosity of 80%. The cathode gas diffusion layer buffer layer 12 is made of carbon powder with a thickness of 0.08 mm and a porosity of 25%. In this embodiment, an elastic buffer layer is also provided between the cathode and anode diffusion layer base layers and buffer layers to adjust the thickness of the gas diffusion layer. The anode elastic buffer layer is made of titanium fiber elastic porous material with a thickness of 0.1 mm, and the cathode elastic buffer layer is made of carbon fiber elastic porous material with a thickness of 0.1 mm. The cathode and anode gas diffusion layer base layers, elastic buffer layers, and buffer layers are integrated structures. In this embodiment, the cathode and anode frames adopt an asymmetrical structure, with the cathode frame thickness of 0.05 mm and the anode frame thickness of 0.1 mm.

[0037] Comparative Example 1

[0038] The other steps of Comparative Example 1 are the same as those of Example 1, except that: in this comparative example, the cathode and anode frames adopt a symmetrical structure, the cathode frame thickness is 0.05mm, and the anode frame thickness is 0.05mm.

[0039] Comparative Example 2

[0040] Comparative Example 2 follows the same steps as Example 1, except that the cathode and anode gas diffusion layers consist of only one base layer, which is in direct contact with the cathode and anode catalyst layers 6, without any buffer layer or elastic buffer layer. In this comparative example, the cathode and anode frames adopt a symmetrical structure, with a cathode frame thickness of 0.05 mm and an anode frame thickness of 0.05 mm.

[0041] Comparative Example 3

[0042] Comparative Example 3 follows the same steps as Example 1, except that the cathode and anode gas diffusion layers consist only of a base layer and a buffer layer, without an elastic buffer layer.

[0043] Figure 2 This is a comparison graph showing the long-term hydrogen content in oxygen of Example 1 and Comparative Example 1 under voltage fluctuation conditions (1.45-2.0 V). It can be seen that Example 1, with its asymmetric frame structure, exhibits a lower hydrogen content in oxygen and a more stable variation in hydrogen content, which will help improve safety during operation. Under a cathode back pressure of 3 MPa, the high voltage on the cathode side will press the CCM towards the anode gas diffusion layer. Example 1, with its asymmetric frame structure, can reserve more space on the anode side, thereby reducing the compression deformation of the CCM by the anode gas diffusion layer, resulting in a lower and more stable hydrogen content in oxygen in Example 1.

[0044] Figure 3 This is a comparison chart of the long-term hydrogen content in oxygen for Example 1 and Comparative Example 2 under voltage fluctuation conditions. It can be seen that Example 1, with its asymmetric border design combined with a gas diffusion layer buffer layer design and an elastic buffer layer structure with thickness adjustment function, exhibits a lower hydrogen content in oxygen and a more stable variation in hydrogen content in oxygen. Figure 4This is a comparison chart of the long-term hydrogen content in oxygen for Example 1 and Comparative Example 3 under voltage fluctuation conditions. It can be seen that, despite other conditions being the same, Example 1 with the elastic buffer layer still exhibits a lower hydrogen content in oxygen and a more stable change in hydrogen content, demonstrating the necessity of the elastic buffer layer. Example 1, by introducing a buffer layer with a smoother surface structure between the gas diffusion layer substrate and the catalyst layer, minimizes the mechanical compressive effects of assembly pressure, cathode-side pressure, and CCM swelling on the cathode and anode interfaces. Adding an elastic buffer layer between the substrate and the buffer layer can absorb some of the assembly pressure, cathode-side pressure, and CCM swelling stress during high-voltage cathode operation, mitigating the extrusion deformation of the gas transport layer and catalyst layer interface. The asymmetric frame structure design also further reduces the extrusion deformation of the CCM by the anode gas diffusion layer. Considering all these factors, Example 1 therefore has a lower and more stable hydrogen content in oxygen.

[0045] Figure 5 , Figure 6 and Figure 7 The figures show a comparison of the long-term current density of Examples 1, 2, and 3 under voltage fluctuation conditions. It can be seen that the current density of Example 1 did not decrease over time, while the current densities of Comparative Examples 2 and 3 gradually decreased. The rate of decrease was faster in Comparative Example 2, indicating that the CCM structure of the membrane electrode in Comparative Examples 2 and 3 was damaged during operation, with Comparative Example 2 experiencing more severe damage, leading to a decline in performance during operation. Under voltage fluctuation conditions, the stress inside the membrane electrode also changes. Example 1, with its elastic buffer layer structure featuring thickness adjustment, can maintain close contact between the gas diffusion layer and the catalyst layer interface at all times, thereby ensuring the stability of water electrolysis performance.

[0046] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure, comprising an anode gas diffusion layer, an anode frame, a catalyst coating film, a cathode frame, and a cathode gas diffusion layer sequentially stacked together. The anode gas diffusion layer includes an anode diffusion layer substrate and an anode buffer layer, the anode buffer layer being located on the side closest to the catalyst coating film. The cathode gas diffusion layer includes a cathode diffusion layer substrate and a cathode buffer layer, the cathode buffer layer being located on the side closest to the catalyst coating film. Its features are, The anode gas diffusion layer further includes an anode elastic buffer layer, which is located between the anode diffusion layer base layer and the anode buffer layer. The cathode gas diffusion layer further includes a cathode elastic buffer layer, which is located between the cathode diffusion layer base layer and the cathode buffer layer.

2. The highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to claim 1, characterized in that, The thickness of the anodic elastic buffer layer is 0.005~1 mm.

3. The highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to claim 1, characterized in that, The porosity of the anode diffusion layer substrate is 76-90%.

4. The highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to claim 1, characterized in that, The thickness of the cathode elastic buffer layer is 0.005~1 mm.

5. A highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to any one of claims 1 to 4, characterized in that, The cathode frame and anode frame are divided into a frame substrate and an adhesive, with the adhesive located on the side close to the catalyst coating film.

6. A highly stable water electrolysis hydrogen production membrane electrode with an interface-optimized structure according to any one of claims 1 to 4, characterized in that, A first gap is reserved in the middle of the anode frame, which is located between the anode gas diffusion layer and the catalyst coating film; a second gap is reserved in the middle of the cathode frame, which is located between the cathode gas diffusion layer and the catalyst coating film.

7. A highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to any one of claims 1 to 4, characterized in that, The thickness of the cathode frame is 0.01~0.15 mm.

8. A highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to any one of claims 1 to 4, characterized in that, The thickness of the cathode frame does not exceed the thickness of the anode frame.

9. A highly stable water electrolysis hydrogen production membrane electrode with an interface-optimized structure according to any one of claims 1 to 4, characterized in that, The ratio of the cathode frame thickness to the catalyst coating film thickness is 0.05~10.

10. A highly stable water electrolysis hydrogen production membrane electrode with an optimized interface structure according to any one of claims 1 to 4, characterized in that, The root mean square deviation of the surface roughness of the anode buffer layer and the cathode buffer layer is 0.1~50 µm.

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