Membrane electrode assembly and manufacturing method therefor, and hydrogen electrolyzer

Abstract

A membrane electrode assembly and a manufacturing method therefor, and a hydrogen electrolyzer. The membrane electrode assembly comprises: a membrane layer; and an electrode catalyst layer formed on one side of the film layer, the surface roughness of the electrode catalyst layer being less than or equal to 0.15 μm.

Description

A membrane electrode, a manufacturing method thereof, and a hydrogen production electrolyzer Technical Field

[0001] The present application relates to the field of hydrogen production technology, and in particular to a membrane electrode, a manufacturing method thereof, and a hydrogen production electrolyzer. Background Art

[0002] As the core component of water electrolysis hydrogen production technology, the membrane electrode is composed of an electrode catalyst layer, an electrode catalyst layer and a membrane layer. It plays the role of conducting protons, catalyzing reactions and separating gases, and determines the performance, efficiency, life and cost of water electrolysis hydrogen production.

[0003] However, in membrane electrodes, the electrode catalyst layer and membrane layer are prone to delamination, resulting in poor membrane electrode stability. Furthermore, during electrolysis, hydrogen can permeate through the membrane layer from the cathode to the anode. The mixing of hydrogen and oxygen can degrade membrane electrode performance and, in severe cases, cause explosions, raising significant safety concerns.

[0004] Application Contents

[0005] To solve the above technical problems, this application is implemented through the following technical solutions.

[0006] The present application provides a membrane electrode, comprising:

[0007] membrane layer;

[0008] An electrode catalyst layer is formed on one side of the membrane layer, wherein the surface roughness of the electrode catalyst is less than or equal to 0.15 μm.

[0009] In summary, the present application can improve the quality of the membrane electrode, while ensuring the uniformity and stability of the catalysis, and extending the service life of the water electrolysis device.

[0010] Of course, any method of implementing the present application does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic diagram of the stacking of layers during the membrane electrode preparation process in one embodiment of the present application.

[0012] FIG2 is an appearance diagram of the proton exchange membrane and the resulting membrane electrode used in one embodiment of the present application.

[0013] FIG3 is a schematic diagram of the stacking of layers during the membrane electrode preparation process according to an embodiment of the present application.

[0014] FIG4 is a schematic flow chart of a method for preparing a membrane electrode in one embodiment of the present application.

[0015] FIG5 is a physical diagram of a membrane electrode in one embodiment of the present application.

[0016] FIG6 is a cross-sectional view of the microscopic morphology of the membrane electrode in FIG5.

[0017] FIG7 is an enlarged view of the membrane layer and the electrode catalyst layer in FIG6 .

[0018] FIG8 is a stability curve diagram of the membrane electrode in FIG5 .

[0019] FIG9 is a schematic diagram of a membrane layer and an electrode catalyst layer in one embodiment of the present application.

[0020] FIG10 is a microscopic morphology diagram of the membrane layer and the electrode catalyst layer in one embodiment of the present application.

[0021] FIG11 is a schematic diagram of the structure of a membrane electrode in one embodiment of the present application.

[0022] FIG12 is a schematic diagram showing the distribution of the hydrogen consumption layer on the film layer in one embodiment of the present application.

[0023] FIG13 is a schematic diagram of a flow channel in a cathode catalyst layer in one embodiment of the present application.

[0024] FIG14 is a schematic diagram showing the distribution of the hydrogen consumption layer on the film layer in another embodiment of the present application.

[0025] FIG15 is a schematic diagram of the structure of the membrane electrode during transfer in one embodiment of the present application.

[0026] FIG16 is a scanning electron microscope image of an electrode catalyst layer obtained by the transfer method of the present application in one embodiment of the present application.

[0027] FIG17 is a scanning electron microscope image of a conventionally obtained electrode catalyst layer.

[0028] FIG18 is a schematic diagram showing adhesion test of the membrane electrode obtained in the present application and the membrane electrode obtained in a conventional manner.

[0029] FIG19 is a schematic diagram of the electrode sheet of the present application.

[0030] Description of the drawings:

[0031] 11. First high-temperature resistant resin membrane layer; 12. First heat-resistant layer; 13. Second high-temperature resistant resin membrane layer; 141. First region; 142. Second region; 211. Third region; 212. Fourth region; 22. Third high-temperature resistant resin membrane layer; 23. Second heat-resistant layer; 24. Fourth high-temperature resistant resin membrane layer; 3. Proton exchange membrane; 100. Membrane layer; 200. Electrode catalyst layer; 201. Fusion region; 300. Electrode catalyst layer; 301. First metal catalyst layer; 302. Second metal catalyst layer; 110. Anode catalyst layer; 111. Hydrogen consumption layer; 112. Anode catalyst base layer; 120. Cathode catalyst layer; 20. Diode plate; 2011. Cathode flow field ridge; 2022. Flow channel; 131. First transfer plate; 132. Second transfer plate; 133. Positioning hole; 134. Positioning piece; 15. First transfer film; 16. Second transfer film. DETAILED DESCRIPTION

[0032] The technical solution of the present application is further described in detail below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0033] As shown in Figures 1 to 3, the present application provides a method for producing a membrane electrode, which comprises:

[0034] S1. Stacking a first high-temperature resistant resin film layer, a first heat-resistant layer with a thickness of 1-5 mm, a second high-temperature resistant resin film layer, and a cathode transfer layer in sequence.

[0035] The material of the first high temperature resistant resin film layer 11 includes at least one of polyimide resin, polytetrafluoroethylene resin, polypropylene resin, polyethylene terephthalate resin and polyamide;

[0036] The material of the first heat-resistant layer 12 includes silicone, rubber or a mixture of the two;

[0037] The material of the second high temperature resistant resin film layer 13 includes at least one of polyimide resin, polytetrafluoroethylene resin, polypropylene resin, polyethylene terephthalate resin and polyamide;

[0038] The cathode transfer layer is composed of a first region 141 and a second region 142. The first region 141 is made of a first cathode transfer substrate, and the second region 142 is made of a second cathode transfer substrate having a cathode active material layer attached to its surface. The first cathode transfer substrate includes at least one of polyimide resin (PI), polytetrafluoroethylene resin (PTFE), polypropylene resin (PP), polyethylene terephthalate resin (PET), and polyamide (PA).

[0039] S2. Then, the proton exchange membrane is stacked on the cathode transfer layer.

[0040] S3. Then, an anode transfer layer, a third high-temperature resistant resin membrane layer, a second heat-resistant layer with a thickness of 1-5 mm, and a fourth high-temperature resistant resin membrane layer are sequentially stacked on the proton exchange membrane to obtain a stacked body.

[0041] The anode transfer layer is composed of a third region 211 and a fourth region 212. The third region 211 is made of a first anode transfer substrate, and the fourth region 212 is made of a second anode transfer substrate having an anode active material layer attached to its surface. The first anode transfer substrate includes at least one of polyimide resin, polytetrafluoroethylene resin, polypropylene resin, polyethylene terephthalate resin, and polyamide.

[0042] The material of the third high temperature resistant resin film layer 22 includes at least one of polyimide resin, polytetrafluoroethylene resin, polypropylene resin, polyethylene terephthalate resin and polyamide;

[0043] The material of the second heat-resistant layer 23 includes silicone, rubber or a mixture of the two;

[0044] The material of the fourth high temperature resistant resin film layer 24 includes at least one of polyimide resin, polytetrafluoroethylene resin, polypropylene resin, polyethylene terephthalate resin and polyamide;

[0045] S4. Hot-press the stack at a temperature of 135-175° C. and a pressure of 3-10 MPa for 1-5 minutes, and then peel off the cathode transfer layer and the anode transfer layer from the proton exchange membrane to obtain a membrane electrode.

[0046] In step S1 , the cathode transfer layer is formed by splicing a plurality of alternately arranged first regions 141 and second regions 142 .

[0047] In step S3 , the anode transfer layer includes a plurality of third regions 211 and fourth regions 212 that are alternately arranged.

[0048] As shown in Figure 2, the proton exchange membrane did not undergo significant deformation before and after transfer. This result demonstrates that this application solves the technical problem of uneven force applied to the membrane during transfer, with greater force applied to locations with the catalytic layer and less force applied to locations without the catalytic layer, which can easily lead to decreased mechanical stability of the membrane and shortened membrane electrode life.

[0049] As shown in FIG3 , in one embodiment, the cathode transfer layer and the anode transfer layer are not partitioned. The cathode transfer layer comprises two spaced-apart cathode transfer substrates (made of PTFE) with cathode active material layers attached to their surfaces. The anode transfer layer comprises multiple spaced-apart cathode transfer substrates (made of PTFE) with cathode active material layers attached to their surfaces.

[0050] Experiments show that in this application, by adding the first high-temperature resistant resin film layer 11, the second high-temperature resistant resin film layer 13, the third high-temperature resistant resin film layer 22 and the fourth high-temperature resistant resin film layer 24, the influence of the proton exchange membrane deformation during the hot pressing process can be effectively alleviated.

[0051] Experiments show that by dividing the cathode transfer layer and the anode transfer layer into zones and introducing inactive areas, the thickness difference between the active area and the inactive area can be reduced, thereby solving the technical problem in the prior art that different areas of the proton exchange membrane are subjected to uneven force during the transfer process, with the positions with the catalytic layer being subjected to greater force and the positions without the catalytic layer being subjected to less force.

[0052] Experiments show that by selecting the thickness of the first heat-resistant layer 12 and the second heat-resistant layer 23 to be within a specific range (1-5 mm), the effect of the deformation of the proton exchange membrane during the hot pressing process can be effectively alleviated.

[0053] In another embodiment, as shown in FIG4 , the present application provides a method for preparing a membrane electrode, which at least includes steps S11 - S15 .

[0054] S11. Provide a film layer, wherein the film layer includes a first surface and a second surface that are opposite to each other.

[0055] S12, coating the precursor solution on the first surface.

[0056] S13, coating the bonding enhancer on the precursor solution.

[0057] S14, placing the membrane layer in an alkaline solution for growth, so as to in-situ grow an electrode catalyst layer on the first surface.

[0058] S15, repeating the above steps on the second surface using the precursor solution, the binding strength enhancer and the alkaline solution to in-situ grow another electrode catalyst layer on the second surface to obtain a membrane electrode.

[0059] As shown in Figures 4 to 6, in one embodiment, in step S11, the membrane layer 100 is, for example, a diaphragm, a cation exchange membrane, an anion exchange membrane, a proton exchange membrane, a porous membrane, or other membrane layer that can be used for hydrogen production electrolysis. The membrane layer 100 includes, for example, a first surface and a second surface disposed opposite each other. Furthermore, the membrane layer 100 is pretreated before use to remove impurities on the surface so that the membrane layer 100 can be tightly bonded to the subsequently formed electrode catalyst layer 200 and electrode catalyst layer 300.

[0060] As shown in Figures 4 to 6, in one embodiment, after providing the film layer 100, before applying the precursor solution in step S12, the precursor solution is homogenized to obtain a uniform precursor solution. In this embodiment, the precursor solution includes, for example, a metal compound and a solution. The metal compound is, for example, selected from at least two of a transition metal compound, a rare earth metal compound, and a noble metal compound. The transition metal compound includes, for example, metal compounds of manganese, chromium, iron, cobalt, nickel, copper, zinc, molybdenum, or tungsten. The rare earth metal compound includes, for example, lanthanide rare earth metal compounds, and the noble metal compound includes, for example, platinum group noble metal compounds.

[0061] As shown in Figures 4 to 6, in one embodiment, after a bonding enhancer is applied to the precursor solution, in step S14, the film layer 100 coated with the bonding enhancer and the precursor solution is immersed in an alkaline solution for growth. The alkaline solution has a pH of, for example, 8-14, and is selected from at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate. The alkaline solution has a temperature of, for example, 30°C to 90°C, and the film layer 100 is immersed in the alkaline solution for, for example, 5 minutes to 1200 minutes.

[0062] As shown in Figures 4 to 6, in one embodiment, in step S14, while the membrane layer 100 is immersed in the alkaline solution, the precursor solution coated on the membrane layer 100 undergoes in-situ growth on the first surface to form the electrode catalyst layer 200. Furthermore, during the in-situ growth process, the bonding agent coated on the precursor solution can enhance the bonding force between the electrode catalyst layer 200 and the membrane layer 100, allowing the electrode catalyst layer 200 and the membrane layer 100 to be closely attached, thereby improving the stability of the membrane electrode.

[0063] As shown in Figures 4 to 6, in one embodiment, after forming the electrode catalyst layer 300 on the second surface and rinsing the membrane layer 100, the membrane layer 100 is dried to obtain a membrane electrode. In the preparation method provided in the present application, in an alkaline solution, a precursor solution and a precursor solution are respectively grown in situ on the first surface and the second surface of the membrane layer 100 to form the electrode catalyst layer 200 on the first surface of the membrane layer 100 and the electrode catalyst layer 300 on the second surface of the membrane layer 100. Moreover, during the in-situ growth process, the precursor solution and the binding agent on the precursor solution can enhance the binding force between the electrode catalyst layer 200 and the first surface, as well as the binding force between the electrode catalyst layer 300 and the second surface, so as to improve the quality and stability of the membrane electrode. Moreover, the preparation method provided in the present application can simplify the preparation process of the membrane electrode, reduce the preparation cycle and cost, and is suitable for large-scale production of membrane electrodes.

[0064] As shown in Figures 4 to 6, the present application also provides a membrane electrode, which is obtained by the above-mentioned membrane electrode preparation method. The membrane electrode, for example, includes a membrane layer 100, an electrode catalyst layer 200, and an electrode catalyst layer 300. Among them, the membrane layer 100 includes a first surface and a second surface arranged opposite to each other, the electrode catalyst layer 200 is, for example, arranged on the first surface, and the electrode catalyst layer 300 is, for example, arranged on the second surface. In the membrane electrode provided in the present application, in an alkaline solution, a precursor solution is in situ grown on the first surface or the second surface to form the electrode catalyst layer 200 or the electrode catalyst layer 300.

[0065] As shown in FIG. 4 and FIG. 5 , in one embodiment, a membrane electrode is obtained according to the membrane electrode preparation method. A physical picture of the membrane electrode is shown in FIG. 5 .

[0066] As shown in Figures 6 and 7, in one embodiment, the membrane electrode in Figure 6 is characterized, for example, by scanning electron microscopy (SEM) of a cross-section of the membrane electrode, and the region between the electrode catalyst layer 200 and the membrane layer 100 is magnified. The magnification in Figure 6 is, for example, 100x, and in Figure 7, 400x. As can be seen from Figures 6 and 7, in the membrane electrode, the electrode catalyst layer 300 and the electrode catalyst layer 200 are located on either side of the membrane layer 100, respectively. Furthermore, a fusion region 201 is present between the electrode catalyst layer 200 and the membrane layer 100. In the fusion region 201, the electrode catalyst layer 200 grows on the membrane layer 100 and diffuses toward the membrane layer 100. At this point, a portion of the electrode catalyst layer 200 is embedded or fused into the membrane layer 100, resulting in a tight bond between the membrane layer 100 and the electrode catalyst layer 200, with good bonding stability. In some embodiments, the depth of the electrode catalyst layer 200 embedded into the membrane layer 100 is, for example, 10 nm to 7 μm.

[0067] It is worth noting that, through the method of the present application, the electrode catalyst layer 200 can be directly grown on opposite sides of the membrane layer 100 to form the membrane electrode of the electrolyzer. However, it is not limited to this. In some embodiments, through the method of the present application, the electrode catalyst layer 200 can also be grown only on one side of the membrane layer 100, and the electrode catalyst can be formed on the other side of the membrane layer 100 on the diffusion layer. That is, in the membrane electrode of the present application, the electrode catalyst layer 200 can be formed on one side or on opposite sides of the membrane layer 100. For example, in the AEM membrane electrode, the electrode catalyst layer 200 can be formed on one side of the membrane layer 100, and the other electrode catalyst layer 200 can be formed on the diffusion layer. In some embodiments, when the electrode catalyst layer 200 or 300 is formed on the diffusion layer, an electrode sheet can be formed.

[0068] As shown in FIG8 , in one embodiment, the stability of the membrane electrode in FIG5 is characterized. Specifically, the membrane electrode is loaded to a preset current density, and the change in the membrane electrode voltage within 100 hours is measured. The preset current density is, for example, 2A / cm 2 As shown in Figure 8, within 0-70h, the voltage of the membrane electrode fluctuates stably around 1.94V and tends to 1.94V. Therefore, the stability of the membrane electrode is relatively good.

[0069] As shown in Figures 9 and 10, in one embodiment, on the anode side of the membrane layer 100, the electrode catalyst layer 300 may include a first metal catalyst layer 301 and a second metal catalyst layer 302. The first metal catalyst layer 301 is formed on the membrane layer 100 and may partially penetrate or embed into the membrane layer 100. The second metal catalyst layer 302 is formed on the first metal catalyst layer 301. The first metal catalyst layer 301 and the second metal catalyst layer 302 may have different metal catalysts. For example, the first metal catalyst layer 301 may include a platinum metal catalyst, and the second metal catalyst layer 302 may include an iridium or iridium oxide metal catalyst. By using different metal catalysts, the use of precious metal (such as iridium) catalysts can be reduced, thereby reducing costs.

[0070] In one embodiment, the thickness of the first metal catalyst layer 301 is, for example, 5 nm to 200 nm, and the thickness of the second metal catalyst layer 302 is, for example, 50 nm to 5 μm.

[0071] In one embodiment, the nanoparticle size of the metal catalyst in the electrode catalyst layer is, for example, 1 nm to 200 nm, or, for example, 1 nm to 30 nm. In one embodiment, the nanoparticle size of the metal catalyst in the first metal catalyst layer 301 is, for example, 1 nm to 20 nm, and the nanoparticle size of the metal catalyst in the second metal catalyst layer 302 is, for example, 10 nm to 200 nm.

[0072] As shown in FIG11 , in another embodiment of the present application, the membrane electrode provided by the present application includes a membrane layer 100, an anode catalyst layer 110, and a cathode catalyst layer 120. The anode catalyst layer 110 and the cathode catalyst layer 120 are respectively formed on both sides of the membrane layer 100. The anode catalyst layer 110 includes a hydrogen consumption layer 111 and an anode catalyst base layer 112. The hydrogen consumption layer 111 is formed between the membrane layer 100 and the anode catalyst base layer 112. By providing the hydrogen consumption layer 111, hydrogen that penetrates from the cathode side to the anode can be eliminated in a timely manner, thereby improving the purity of the gas and enhancing the safety of the water electrolysis hydrogen production device.

[0073] As shown in FIG. 11 , in one embodiment, the membrane layer 100 is, for example, a proton membrane, and the thickness of the membrane layer 100 is, for example, 110 μm to 130 μm, for example, 127 μm, to meet the requirements of conductivity, isolation, and thermal stability.

[0074] As shown in FIG11 , in one embodiment, the hydrogen-scavenging catalyst in the hydrogen-consuming layer 111 is selected from a highly active, acid-resistant, and stable material such as Pt, Ir, or Pd. The anode catalyst in the anode catalyst substrate 112 is selected from a catalyst for catalyzing oxygen reactions, such as at least one of Ir, IrO2, Pt, Pd, or Ru. The hydrogen-scavenging catalyst in the hydrogen-consuming layer 111 can convert hydrogen diffused from the cathode into hydrogen ions, causing a portion of the oxygen generated on the anode side to diffuse into the hydrogen-consuming layer 111. The hydrogen-scavenging catalyst in the hydrogen-consuming layer 111 can also convert the oxygen diffused into the hydrogen-consuming layer 111 into oxygen ions, causing the hydrogen ions and oxygen ions to react to form water. This eliminates hydrogen on the anode side, improves the purity of oxygen on the anode side, and prevents oxygen from diffusing to the cathode. This improves the purity of both hydrogen and oxygen generated by water electrolysis, thereby enhancing the safety of the water electrolysis device.

[0075] As shown in FIG11 , in one embodiment, the cathode catalyst in the cathode catalyst layer 120 is, for example, a catalyst for catalyzing hydrogen reaction, and is, for example, at least one of Ir, IrO 2 , Pt / C, Pt, Pd, or Ru.

[0076] As shown in Figure 11, in one embodiment, the thickness ratio of the membrane layer 100, the anode catalyst layer 110, and the cathode catalyst layer 120 is, for example, 1:0.1:0.1 to 1:10:10, or 1:1.5:1.5, and the thickness ratio of the hydrogen-consuming layer 111 to the anode catalyst-based layer 112 is, for example, 1:1 to 1:10, or 1:5, or 1:1. In a specific embodiment of the present application, the total thickness of the membrane electrode is, for example, 154 μm. The membrane electrode within this thickness range, and the thickness of the different layers are coordinated, can improve the efficiency of the membrane electrode water electrolysis.

[0077] As shown in FIG. 11 , in one embodiment, the porosity of the hydrogen consumption layer 111 is, for example, 1 m 2 / g, and the porosity of the anode catalyst substrate 112 is, for example, 100 to 330 m 2 / g, and the porosity of the cathode catalyst layer 120 is, for example, 100 to 330 m 2 In a specific embodiment of the present application, the porosity of the hydrogen consumption layer 111 is, for example, 130 m 2 / g, the porosity of the anode catalyst substrate 112 is, for example, 160m 2 / g, the porosity of the cathode catalyst layer 120 is, for example, 180m 2The anode catalyst layer 110 and the cathode catalyst layer 120 on both sides of the membrane layer 100 have a large porosity, which can increase the number of membrane electrode pores, provide abundant pores for mass transfer, and thus improve the electrolysis rate.

[0078] As shown in Figure 12, in one embodiment, a schematic diagram of the distribution of the hydrogen-consuming layer 111 on the membrane layer 100 is provided. During the electrolysis process, hydrogen permeating through the membrane layer 100 gradually accumulates from the inlet to the outlet of the anode layer flow field. In some embodiments, the loading of the hydrogen-consuming layer 111 can increase along the direction of water flow in the anode catalyst layer. Therefore, on the anode side of the membrane layer 100, the hydrogen-consuming layer 111 on the membrane layer 100 increases from the end of the membrane electrode away from the water flow direction to the end closer to the water flow direction, such as by increasing the width, loading, and density of the hydrogen-scavenging catalyst in the hydrogen-consuming layer 111. In part a of Figure 12, the hydrogen-consuming layer 111 comprises a plurality of arranged strip-like structures. The width of the strips of the hydrogen-consuming layer 111 increases progressively at the end closer to the water flow direction. In part b of Figure 12, the loading of the hydrogen-consuming layer 111 increases progressively at the end closer to the water flow direction, such as by increasing the thickness of the hydrogen-consuming layer 111. In section c of Figure 12 , the density of hydrogen-scavenging catalyst within hydrogen-consuming layer 111 increases gradually toward the water flow direction. By providing varying amounts of hydrogen-scavenging layer 111 in different regions of membrane layer 100, the efficiency of hydrogen removal on the anode side can be improved while reducing the amount of hydrogen-scavenging catalyst used and lowering costs.

[0079] As shown in Figures 13 and 14, in another embodiment of the present application, a schematic diagram of the distribution of the hydrogen consumption layer 111 on the membrane layer 100 is provided. The electrolyzer includes a membrane electrode 10 and a diode 20, and the diode 20 is located on the outside of the anode catalyst layer and the cathode catalyst layer of the membrane electrode, respectively. During the electrolysis process, the cathode flow field ridge 2011 of the diode 20 on the cathode catalyst layer side is compressed by the membrane layer 100 at the contact portion of the membrane layer 100, which is not conducive to hydrogen permeation. The hydrogen content is low, and the membrane layer 100 at the flow channel 2022 position swells, with more microporous channels, which is conducive to hydrogen permeation. In some embodiments, the hydrogen consumption layer 111 can be provided with a bent structure (as shown in Figure 14), and the bent structure of the hydrogen consumption layer 111 can be consistent with the flow field distribution of the electrode plate outside the cathode catalyst layer. The hydrogen diffused from the flow channel 2022 can be consumed, which can improve the removal efficiency of hydrogen on the anode side and improve the safety of electrolysis.

[0080] In one embodiment, the present application further provides a method for preparing a membrane electrode, comprising steps S11-S12.

[0081] Step S11: forming an anode catalyst layer on one side of the membrane layer. The anode catalyst layer includes a hydrogen consumption layer and an anode catalyst base layer. The hydrogen consumption layer is formed between the membrane layer and the anode catalyst base layer.

[0082] Step S12: forming a cathode catalyst layer on the other side of the membrane layer.

[0083] In one embodiment, the electrode catalyst layer (the anode catalyst layer and / or the cathode catalyst layer) can be formed, for example, by transfer printing. When transferring simultaneously, the anode catalyst base layer is formed on the transfer film, and the hydrogen-consuming layer is formed on the anode catalyst base layer before being transferred to the membrane layer. When transferring in stages, the hydrogen-consuming layer is first transferred to the membrane layer, and then the anode catalyst base layer is transferred to the anode catalyst base layer. In this embodiment, for example, non-vacuum hot pressing transfer is used for transfer.

[0084] As shown in FIG15 , in one embodiment, an anode catalyst slurry layer and a hydrogen-consuming slurry layer are formed on a transfer film to form a first transfer film 15. The anode catalyst slurry layer includes, for example, an anode catalyst and a resin. The anode catalyst includes a carrier and a component containing an active metal element supported on the carrier. The mass ratio of the anode catalyst to the resin is, for example, 1:0.1 to 1:3. The hydrogen-consuming slurry layer includes, for example, a hydrogen-scavenging catalyst and a resin. The hydrogen-scavenging catalyst includes a carrier and a component containing an active metal element supported on the carrier. The mass ratio of the hydrogen-scavenging catalyst to the resin is, for example, 1:0.5 to 1:3. The hydrogen-scavenging slurry layer is formed, for example, by doctor blade coating, roller coating, or spraying.

[0085] As shown in FIG15 , in one embodiment, a cathode catalyst slurry layer is formed on a transfer film to form a second transfer film 16. The cathode catalyst slurry layer includes a cathode catalyst and a resin. The cathode catalyst includes a carrier and a component containing an active metal element supported on the carrier. The mass ratio of the cathode catalyst to the resin is, for example, 1:0.7 to 1:2. The cathode catalyst slurry layer is formed, for example, by doctor blade coating, roller coating, or spraying.

[0086] In one embodiment, the resins in the anode catalyst slurry layer, the hydrogen consumption slurry layer, and the cathode catalyst slurry layer may be the same or different, wherein the resin is, for example, at least one selected from perfluororesin solution (D2020).

[0087] As shown in FIG15 , in one embodiment, when the membrane electrode is formed by transfer printing using a transfer assembly, the membrane layer 100 is placed in the middle position to ensure that the membrane layer 100 is flat and has no folds. Transfer plates are provided on both sides of the membrane layer 100, for example, including a first transfer plate 131 and a second transfer plate 132. The first transfer plate 131 and the second transfer plate 132 are of the same size. Openings of the same size and position are provided in the center of the first transfer plate 131 and the second transfer plate 132 to determine the transfer area, ensuring that after transfer on both sides of the membrane layer 100, the areas where the catalytic layers are located are of the same size and aligned. Air in the transfer process or water vapor generated by heating can be discharged from the edges of the openings.

[0088] As shown in FIG15 , in one embodiment, positioning holes 133 are provided at diagonal positions of the first transfer plate 131 and the second transfer plate 132, and the positions of the positioning holes 133 on the first transfer plate 131 and the second transfer plate 132 are the same. During transfer, the membrane layer 100 is placed between the first transfer plate 131 and the second transfer plate 132, and positioning members 134 are placed in the diagonal positioning holes 133. The positioning members 134 are, for example, fluororubber to fix and position the membrane layer of the membrane electrode for subsequent transfer processes. By providing the transfer plate and positioning members, it is possible to remove air from the gap in the middle area of ​​the sheet or water vapor generated by heating during the mold closing process, thereby avoiding large-area bubble defects in the catalyst area after transfer, thereby improving the quality of the membrane electrode. At the same time, the anode catalyst layer and the cathode catalyst layer are aligned on both sides of the membrane layer to ensure the uniformity and stability of the catalysis and extend the service life of the water electrolysis device.

[0089] As shown in Figures 16 to 18, by the manufacturing method of the membrane electrode of the present application, compared with the traditional electrode catalyst layer (as shown in Figure 17), an electrode catalyst layer with good surface uniformity (as shown in Figure 16) can be obtained. In some embodiments, the surface roughness Ra of the electrode catalyst layer (anode catalyst layer and / or cathode catalyst layer) of the present application may be less than or equal to 0.15μm, for example, 0.08μm to 0.15. Furthermore, as shown in Figure 18, by the manufacturing method of the membrane electrode of the present application (as shown in Figure 18 a), compared with the traditional electrode catalyst layer (as shown in Figure 18 b and c), after different adhesion forces (for example 1N / cm 2 and 4N / cm 2 ) test, the catalyst layer of the membrane electrode of the present application (such as a in Figure 18) will not peel off and has good stability. Among them, the bonding force between the electrode catalyst layer and the membrane layer can be greater than 0.8N / cm 2 , for example, 1 to 10 N / cm 2 .

[0090] It is worth noting that in the present application, the electrode catalyst layer of the membrane electrode can be formed on the membrane layer by in-situ growth or transfer methods, and the hydrogen consumption layer of the anode catalyst layer can also be formed on the membrane layer by in-situ growth or transfer methods. In one embodiment, a portion of the hydrogen consumption layer of the anode catalyst layer can be embedded or fused into the membrane layer.

[0091] As shown in Figures 11 and 15, in one embodiment, after the transfer is completed, the anode catalyst layer 110 and / or the cathode catalyst layer 120 can also be subjected to a catalyst pore-forming treatment, for example, by using a hot and cold cycle pore-forming method. Specifically, the membrane electrode is immersed in water in a negative pressure environment. After the membrane electrode is fully swollen, the membrane electrode is slowly cooled, for example, to -50°C, kept warm for 12 hours, and then slowly heated to 70°C, and the cycle is repeated to increase the pore distribution of the catalyst. In this embodiment, the pressure of the negative pressure environment is, for example, 80KPa, the cooling rate is, for example, 0.5°C / min to 3°C / min, and the heating rate is, for example, 0.5°C / min to 3°C / min. The improved pore-forming treatment method of the present application is simple and easy to operate, and after the pore-forming treatment, the pore distribution of the catalyst can be increased, the porosity of the catalyst can be increased, the electrolysis rate can be increased, and the electrolysis efficiency can be improved. In one embodiment, the pore size of the pores in the electrode catalyst layer is, for example, 1μm to 200μm.

[0092] The present application also provides a water electrolysis device, which is, for example, a proton exchange membrane water electrolysis hydrogen production device, including a membrane electrode as described above. When the membrane electrode is applied to the hydrogen production device, it can cause the hydrogen and oxygen on the anode side to react to produce water, thereby achieving the purpose of eliminating hydrogen on the anode side, thereby improving the purity of oxygen on the anode side and improving the safety of the water electrolysis device. At the same time, the quality of the membrane electrode is improved, the uniformity and stability of the catalysis are ensured, and the service life of the water electrolysis device is extended. It can increase the electrolysis rate and improve the electrolysis efficiency, which is conducive to promoting the development of water electrolysis hydrogen production technology.

[0093] It is worth noting that the membrane electrode or electrode sheet of the present application can be used in suitable electrolytic cells, such as proton exchange membrane (PEM) electrolytic cells, anion exchange membrane (AEM) electrolytic cells, alkaline solution electrolytic cells, solid oxide electrolytic cells (SOEC) or other electrolytic cells.

[0094] In some embodiments, the electrode catalyst layer may include nanoparticles, nanowires, nanochains or other nanostructures. In some embodiments, the precious metal (e.g., platinum) or alloy inside and on the surface of the nanostructure of the electrode catalyst may have different proportions, or may vary in a gradient to improve the catalytic performance of the electrode. For example, the nanostructure of the electrode catalyst 200 or 300 may include a first metal catalyst layer and a second metal catalyst layer, the second metal catalyst layer being formed on the first metal catalyst layer, wherein the alloy ratio of the first metal catalyst is different from the alloy ratio of the second metal catalyst layer. For example, the precious metal ratio of the outer second metal catalyst layer may be higher than the precious metal ratio of the inner first metal catalyst layer. In one embodiment, the number of precious metal nanoparticles in the outer second metal catalyst layer may be higher than the number of precious metal nanoparticles in the inner first metal catalyst layer. Since precious metal (e.g., platinum) catalysts may have better activity, the external catalytic efficiency of the nanostructure of the electrode catalyst may be improved by having different alloy ratios or different numbers of metal nanoparticles inside and outside the nanostructure of the electrode catalyst.

[0095] In some embodiments, when the electrode catalyst layer 200 or 300 is formed on the diffusion layer, an electrode sheet can be formed. In this case, the coverage of the electrode catalyst layer on one side of the diffusion layer can be, for example, greater than or equal to 70%, such as shown in Figure 19. In this way, the high coverage of the electrode catalyst layer on the diffusion layer can improve the catalytic performance of the electrode. In one embodiment, the coverage of the electrode catalyst layer on one side of the diffusion layer can be, for example, 75% to 99%. In one embodiment, the electrode catalyst layer can be formed on two opposite side surfaces of the diffusion layer, and the coverage of the electrode catalyst layer on one side of the diffusion layer can be, for example, greater than or equal to 70%, such as 75% to 99%.

[0096] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A membrane electrode, comprising: Membrane layer; The electrode catalyst layer is formed on at least one side of the membrane layer, wherein the surface roughness of the electrode catalyst is less than or equal to 0.15 μm. 2 . The membrane electrode according to claim 1 , wherein the surface roughness of the electrode catalyst is 0.08 μm to 0.15 μm.

3. The membrane electrode according to claim 1, further comprising another electrode catalyst layer formed on the diffusion layer on the other side of the membrane layer.

4. The membrane electrode according to claim 1, wherein there is a fusion region between the electrode catalyst layer and the membrane layer, in which a portion of the electrode catalyst layer is embedded or fused into the membrane layer, and the depth at which the electrode catalyst layer is embedded in the membrane layer is 10 nm to 7 μm.

5. The membrane electrode according to claim 4, further comprising another electrode catalyst layer formed on the other side of the membrane layer, wherein a portion of the other electrode catalyst layer is embedded or fused into the membrane layer.

6. The membrane electrode according to claim 4, further comprising another electrode catalyst layer formed on the diffusion layer on the other side of the membrane layer.

7. The membrane electrode according to claim 1, wherein the electrode catalyst layer is an anode catalyst layer, the anode catalyst layer comprises a hydrogen consumption layer and an anode catalyst substrate, and the hydrogen consumption layer is formed between the membrane layer and the anode catalyst substrate.

8. The membrane electrode according to claim 7, wherein a portion of the hydrogen consumption layer of the anode catalyst layer is embedded or fused into the membrane layer.

9. The membrane electrode according to claim 7, wherein the electrode catalyst layer includes a cathode catalyst layer, the cathode catalyst layer is arranged on a side of the membrane layer relative to the anode catalyst layer, and the thickness ratio of the membrane layer, the anode catalyst layer and the cathode catalyst layer is 1:0.1:0.1 to 1:10:

10. 10 . The membrane electrode according to claim 7 , wherein a thickness ratio of the hydrogen consumption layer to the anode catalyst layer is 1:1 to 1:

10.

11. The membrane electrode according to claim 7, wherein the hydrogen consuming layer comprises a plurality of arranged strip structures. 12 . The membrane electrode according to claim 11 , wherein the width of the strip structure of the hydrogen consumption layer increases gradually at one end close to the water flow direction. 13 . The membrane electrode according to claim 7 , wherein the thickness of the hydrogen consumption layer increases gradually at one end closer to the water flow direction. 14 . The membrane electrode according to claim 7 , wherein the density of the hydrogen-scavenging catalyst of the hydrogen-consuming layer increases gradually at the end close to the water flow direction.

15. The membrane electrode according to claim 1, wherein the bonding force between the electrode catalyst layer and the membrane layer is greater than 0.8 N / cm 2 . 16 . The membrane electrode according to claim 1 , wherein the electrode catalyst layer has pores, and the pore size of the electrode catalyst layer is, for example, 1 μm to 200 μm. 17 . The membrane electrode according to claim 1 , wherein the nanoparticle size of the metal catalyst of the electrode catalyst layer is 1 nm to 30 nm.

18. The membrane electrode according to claim 1, wherein the electrode catalyst layer comprises a first metal catalyst layer and a second metal catalyst layer, the first metal catalyst layer is formed on the membrane layer, and the second metal catalyst layer is formed on the first metal catalyst layer.

19. A hydrogen production electrolyzer comprising the membrane electrode according to claim 1.

20. A method for manufacturing a membrane electrode, comprising: An electrode catalyst layer is formed on at least one side of the membrane layer; The surface roughness of the electrode catalyst is less than or equal to 0.15 μm.

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