Anode porous transmission layer for PEM water electrolysis hydrogen production and preparation method of anode porous transmission layer

Abstract

The invention discloses an anode porous transmission layer for PEM water electrolysis hydrogen production and a preparation method of the anode porous transmission layer. The preparation method comprises the steps that firstly, a porous titanium plate and a titanium mesh are washed and dried after being subjected to acid pickling; secondly, absolute ethyl alcohol, polyvinyl butyral and titanium powder are evenly mixed to be prepared into slurry, and the slurry is sprayed to the two sides of the dried titanium mesh; and 3, stacking the porous titanium plate and the titanium mesh sprayed with the slurry, and forming metallurgical bonding through vacuum diffusion welding to obtain the anode porous transmission layer. The porous titanium plate and the titanium mesh are metallurgically bonded to prepare the anode porous transmission layer, the platinum plating amount is effectively reduced and the catalyst utilization rate is improved by regulating and controlling the thickness and the pore structure of the porous titanium plate and the plate-mesh stacking mode, and the gas-liquid transmission efficiency of the anode porous transmission layer is improved; and the anode porous transmission layer with strong mechanical support and high gas-liquid transmission efficiency is obtained, is suitable for PEM water electrolysis hydrogen production, and meets the development requirements of high efficiency and low cost of hydrogen production through renewable energy source and PEM water electrolysis coupling.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen production by electrolysis of water, and particularly relates to an anode porous transmission layer for PEM water electrolysis hydrogen production and a preparation method thereof. Background Art

[0002] In PEM water electrolysis for hydrogen production, the anode porous transport layer (PTL) is a key component connecting the anode catalyst layer to the bipolar plate. It performs the core functions of electron conduction, reaction gas (oxygen) exhaust, reaction water transport, and heat transfer, while also providing mechanical support for the catalyst layer. Because the anode is exposed to an acidic, high-oxidizing potential environment, PTL materials must possess excellent corrosion resistance. Currently, titanium-based materials (such as titanium mesh, titanium fiber felt, and titanium powder sintered bodies) are the mainstream, often used in conjunction with platinum plating.

[0003] PTL structural parameters (porosity, pore size, and thickness) significantly influence electrolytic performance. High porosity and pore size facilitate oxygen escape and water permeation, but can reduce electronic conduction efficiency and mechanical strength. Optimizing the structure to achieve a balance between mass transfer and electrical conductivity is crucial. A suitable pore size distribution reduces gas blocking and ensures continuous reaction. Smaller porosity and pore size effectively increase the contact area with the catalyst layer, improving catalyst utilization and cell efficiency. Furthermore, PTL thickness is a key factor influencing the amount of platinum deposited. Generally, thinner PTLs result in lower platinum deposits and lower costs. However, reduced PTL thickness reduces mechanical stability, which in turn shortens the lifespan of the electrolyzer. Therefore, optimizing the PTL design and developing a method to successfully fabricate an anode porous transport layer with low platinum deposits, high catalyst utilization, strong mechanical support, and high gas-liquid transport efficiency are crucial to meet the development needs of efficient and low-cost hydrogen production coupled with renewable energy and PEM water electrolysis. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a method for preparing an anode porous transport layer for PEM water electrolysis hydrogen production. This method metallurgically combines a porous titanium plate and a titanium mesh to prepare the anode porous transport layer. By regulating the thickness and pore structure of the porous titanium plate and the plate-mesh stacking method, the amount of platinum plating is effectively reduced, the catalyst utilization rate is increased, and the gas-liquid transmission efficiency of the anode porous transport layer is improved, thereby obtaining an anode porous transport layer with strong mechanical support and high gas-liquid transmission efficiency. This solves the problem of the lack of an anode porous transport layer with low platinum plating amount, high catalyst utilization rate, strong mechanical support and high gas-liquid transmission efficiency in the prior art.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing an anode porous transport layer for PEM water electrolysis hydrogen production, characterized in that the method metallurgically combines a porous titanium plate and a titanium mesh to prepare the anode porous transport layer, specifically comprising the following steps: Step 1: At room temperature, the porous titanium plate and the titanium mesh are pickled in an oxalic acid ethanol solution with a volume concentration of 1% to 50% for 1 hour to 15 hours, and then washed with an ethanol solution and dried; Step 2: Evenly mix anhydrous ethanol, polyvinyl butyral and titanium powder to prepare a slurry, and then spray the slurry on both sides of the titanium mesh dried in step 1; Step 3: Stack the porous titanium plate dried in step 1 and the titanium mesh sprayed with slurry in step 2 in the order of plate-mesh, and the mesh size of the titanium mesh gradually increases in the direction away from the porous titanium plate, and then form a metallurgical bond by vacuum diffusion welding to obtain a porous anode transport layer for PEM water electrolysis hydrogen production.

[0006] In the anode porous transport layer, the thinner the porous titanium plate, the less platinum is plated, and the higher the gas-liquid transport efficiency, but this results in reduced mechanical strength. The smaller the porosity and pore size of the porous titanium plate, the greater the actual contact area between it and the catalyst layer after assembly into the electrolyzer, improving catalyst utilization, but also resulting in reduced gas-liquid transport efficiency. Furthermore, platinum plating involves covering all exposed surfaces and pore walls of the entire anode porous transport layer with platinum. Therefore, the thinner the porous titanium plate, the fewer pores, and the smaller the pore wall area, the less platinum is plated, and the lower the cost. Therefore, a balance needs to be found.

[0007] The above-mentioned method for preparing a porous transport layer of an anode for PEM water electrolysis to produce hydrogen is characterized in that the thickness of the porous titanium plate in step 1 is 0.05mm~0.15mm, the average pore size is 2µm~60µm, the thickness of the titanium mesh is 0.05mm~0.5mm, and the mesh size is between 0.2mm×1mm and 6mm×10mm.

[0008] The above-mentioned method for preparing a porous transport layer of an anode for PEM water electrolysis to produce hydrogen is characterized in that the mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder in the slurry in step 2 is 10~100:1:10~100, and the particle size of the titanium powder does not exceed 30µm.

[0009] The above-mentioned method for preparing a porous transport layer of an anode for PEM water electrolysis to produce hydrogen is characterized in that, during the stacking in step three, the number of titanium mesh layers after spraying the slurry is not less than 2 layers.

[0010] The above-mentioned method for preparing a porous transport layer of an anode for hydrogen production by electrolysis of water by PEM is characterized in that the temperature of the vacuum diffusion welding in step 3 is 1000°C to 1300°C, the time is 1h to 15h, and the vacuum degree is not more than 1×10 -2 Pa, pressure is 0.2MPa~3MPa.

[0011] In addition, the present invention also discloses an anode porous transport layer for PEM water electrolysis hydrogen production prepared by the above method, characterized in that the anode porous transport layer has a total thickness of 0.2mm~2mm, an average pore size of 2µm~50µm, and an air permeability of 20m 3 / h·kPa·m 2 ~4000m 3 / h·kPa·m 2 , the tensile strength is 100MPa~500MPa.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The present invention metallurgically combines a porous titanium plate and a titanium mesh to prepare an anode porous transport layer. By regulating the thickness and pore structure of the porous titanium plate and the plate-mesh stacking method, the amount of platinum plating is effectively reduced and the catalyst utilization rate is improved. The titanium mesh not only provides mechanical support for the porous titanium plate, but also improves the gas-liquid transmission efficiency of the anode porous transport layer. It can even replace the bipolar plate flow channel commonly used after it is assembled in the electrolyzer, thereby obtaining an anode porous transport layer with strong mechanical support and high gas-liquid transmission efficiency, which is suitable for PEM water electrolysis to produce hydrogen.

[0013] 2. The present invention ensures the surface roughening of the porous titanium plate and the titanium mesh by controlling the concentration of the oxalic acid ethanol solution and the pickling time for pickling the porous titanium plate and the titanium mesh, which is not only conducive to the adhesion of titanium powder in the subsequent slurry to the surface of the titanium mesh, but also promotes the metallurgical bonding of the porous titanium plate and the titanium mesh, ensuring the smooth preparation of the anode porous transport layer.

[0014] 3. The present invention reduces the platinum-plated surface area by controlling the size, especially the thickness, of the porous titanium plate, thereby effectively reducing the coating amount of the subsequent anode porous transport layer.

[0015] 4. The present invention controls the mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder in the slurry sprayed on both sides of the titanium mesh, and limits the particle size of the titanium powder to no more than 30µm. The highly active small-particle titanium powder plays a role similar to that of a flux in the vacuum diffusion welding process, and forms a metallurgical bond with the porous titanium plate and titanium mesh in contact with it, thereby ensuring a good metallurgical bond between the porous titanium plate and the titanium mesh.

[0016] 5. The present invention effectively regulates the gas-liquid transmission efficiency by controlling the number of layers of the titanium mesh during stacking and gradually increasing the mesh size in the direction away from the porous titanium plate. That is, the gas-liquid transmission efficiency is increased by utilizing the characteristic that the mesh size of the titanium mesh is larger than the pore size of the porous titanium plate. The larger the mesh size and the farther away from the porous titanium plate, the higher the gas-liquid transmission efficiency. It can also reduce the number and requirements of bipolar plate flow channels and provide good mechanical support for the porous titanium plate to prevent it from deformation and instability during use.

[0017] 6. The present invention achieves good metallurgical bonding between the porous titanium plate and the titanium mesh by controlling the temperature, time, vacuum and pressure of the diffusion welding under the coordination of the above process parameters, thereby ensuring the service life of the anode porous transport layer.

[0018] 7. The anode porous transport layer for PEM water electrolysis hydrogen production of the present invention can be flexibly adjusted according to working conditions by adjusting the thickness and pore structure of the components to achieve the adjustment of the performance of the anode porous transport layer, including mechanical strength, catalyst utilization, coating amount, etc. The operation is simple and easy, meeting the development needs of high-efficiency and low-cost hydrogen production coupled with renewable energy and PEM water electrolysis.

[0019] The technical solution of the present invention is further described in detail below through examples. DETAILED DESCRIPTION

[0020] Example 1 This embodiment includes the following steps: Step 1: At room temperature, a porous titanium plate with a thickness of 0.05 mm and an average pore size of 2 µm, a first titanium mesh with a thickness of 0.05 mm and a mesh size of 0.2 mm × 1 mm, and a second titanium mesh with a thickness of 0.08 mm and a mesh size of 3 mm × 4 mm were pickled in a 1% by volume oxalic acid-ethanol solution for 1 h, then washed with an ethanol solution and dried; Step 2: Mix anhydrous ethanol, polyvinyl butyral, and titanium powder with a particle size of 1µm to 3µm in a mass ratio of 10:1:10 to form a slurry, and then spray the slurry on both sides of the first and second titanium meshes dried in step 1; Step 3: The porous titanium plate dried in step 1 and the first titanium mesh and the second titanium mesh sprayed with the slurry in step 2 are stacked in the order of porous titanium plate, first titanium mesh, and second titanium mesh, and then heated at a temperature of 1000 ° C, a time of 1 h, and a vacuum degree of 8.4×10 -3 A metallurgical bond was formed by vacuum diffusion welding under the conditions of 0.5 MPa and a pressure of 0.2 MPa to obtain an anode porous transport layer for PEM water electrolysis to produce hydrogen.

[0021] After testing, the total thickness of the porous transport layer of the anode for PEM water electrolysis hydrogen production prepared in this embodiment is 0.2mm, the average pore size is 2µm, and the air permeability is 22m 3 / h·kPa·m 2 , the tensile strength is 498MPa.

[0022] Example 2 The difference between this example and Example 1 is that in step 1, the thickness of the porous titanium plate is 0.1 mm and the average pore size is 31 μm, the thickness of the first titanium mesh is 0.1 mm and the mesh size is 1 mm × 2 mm, the thickness of the second titanium mesh is 0.3 mm and the mesh size is 4 mm × 7 mm, the volume concentration of the oxalic acid ethanol solution is 25%, and the pickling time is 8 h.

[0023] After testing, the total thickness of the porous transport layer of the anode for PEM water electrolysis hydrogen production prepared in this embodiment is 0.6mm, the average pore size is 28µm, and the air permeability is 933m 3 / h·kPa·m 2 , the tensile strength is 310MPa.

[0024] Example 3 The difference between this example and Example 1 is that in step 1, the thickness of the porous titanium plate is 0.15 mm and the average pore size is 60 μm, the thickness of the first titanium mesh is 0.3 mm and the mesh size is 2 mm × 4 mm, the thickness of the second titanium mesh is 0.5 mm and the mesh size is 6 mm × 10 mm, the volume concentration of the oxalic acid ethanol solution is 50%, and the pickling time is 15 h.

[0025] After testing, the total thickness of the porous transport layer of the anode for PEM water electrolysis hydrogen production prepared in this embodiment is 1.0 mm, the average pore size is 50 μm, and the air permeability is 3983 m 3 / h·kPa·m 2 , the tensile strength is 102MPa.

[0026] Example 4 The difference between this example and Example 1 is that in step 2, the mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder is 50:1:44, and the particle size of the titanium powder is 12 μm~17 μm.

[0027] After testing, the total thickness of the porous transport layer of the anode for PEM water electrolysis hydrogen production prepared in this embodiment is 0.21mm, the average pore size is 4.1µm, and the air permeability is 323m 3 / h·kPa·m 2 , the tensile strength is 375MPa.

[0028] Example 5 The difference between this example and Example 1 is that in step 2, the mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder is 98:1:44, and the particle size of the titanium powder is 23 μm~28 μm.

[0029] After testing, the total thickness of the porous transport layer of the anode for PEM water electrolysis hydrogen production prepared in this embodiment is 0.22mm, the average pore size is 3.9µm, and the air permeability is 248m 3 / h·kPa·m2 , the tensile strength is 422 MPa.

[0030] Example 6 The difference between the present example and Example 1 is that the mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder in step two is 100:1:100.

[0031] It is detected that the total thickness of the anode porous transport layer for PEM electrolysis of water to produce hydrogen prepared in the present example is 0.24 mm, the average pore size is 3.5 µm, and the gas permeability is 86 m 3 / h·kPa·m 2 , the tensile strength is 441 MPa.

[0032] Example 7 The difference between the present example and Example 1 is that the third titanium mesh is further included in step one, the thickness of the third titanium mesh is 0.4 mm, and the mesh size is 5 mm×7 mm; the slurry is further sprayed on both sides of the third titanium mesh in step two; the dried porous titanium plate, the first titanium mesh and the second titanium mesh, and the third titanium mesh are stacked in the order of the porous titanium plate, the first titanium mesh, the second titanium mesh, and the third titanium mesh in step three, the temperature of vacuum diffusion welding is 1150℃, the time is 8 h, the vacuum degree is 7.2×10 -3 Pa, and the pressure is 1.5 MPa.

[0033] It is detected that the total thickness of the anode porous transport layer for PEM electrolysis of water to produce hydrogen prepared in the present example is 0.62 mm, the average pore size is 3.3 µm, and the gas permeability is 82 m 3 / h·kPa·m 2 , the tensile strength is 467 MPa.

[0034] Example 8 The difference between the present example and Example 1 is that the temperature of vacuum diffusion welding in step three is 1300℃, the time is 15 h, and the pressure is 3 MPa.

[0035] It is detected that the total thickness of the anode porous transport layer for PEM electrolysis of water to produce hydrogen prepared in the present example is 0.95 mm, the average pore size is 42 µm, and the gas permeability is 3115 m 3 / h·kPa·m 2 , the tensile strength is 131 MPa.

[0036] Example 9 The difference between the present example and Example 1 is that the temperature of vacuum diffusion welding in step three is 1280℃, the time is 14 h, the vacuum degree is 6.5×10 -3 Pa, and the pressure is 2.8 MPa.

[0037] The total thickness of the prepared porous transport layer of the anode for hydrogen production by electrolysis of water using PEM is 0.20 mm, the average pore size is 2.5 µm, the gas permeability is 53 m 3 / h·kPa·m 2 , and the tensile strength is 492 MPa.

[0038] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application. Any simple modification, change and equivalent change of the above embodiments according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing a porous transport layer of an anode for PEM water electrolysis to produce hydrogen, characterized in that: The method comprises metallurgically bonding a porous titanium plate and a titanium mesh to prepare an anode porous transport layer, and specifically comprises the following steps: Step 1: At room temperature, the porous titanium plate and the titanium mesh are pickled in an oxalic acid ethanol solution with a volume concentration of 1% to 50% for 1 hour to 15 hours, and then washed with an ethanol solution and dried; Step 2: Evenly mix anhydrous ethanol, polyvinyl butyral and titanium powder to prepare a slurry, and then spray the slurry on both sides of the titanium mesh dried in step 1; Step 3: Stack the porous titanium plate dried in step 1 and the titanium mesh sprayed with slurry in step 2 in the order of plate-mesh, and the mesh size of the titanium mesh gradually increases in the direction away from the porous titanium plate, and then form a metallurgical bond by vacuum diffusion welding to obtain a porous anode transport layer for PEM water electrolysis hydrogen production.

2. The method for preparing a porous transport layer of an anode for producing hydrogen by electrolysis of water by PEM according to claim 1, wherein: The thickness of the porous titanium plate in step 1 is 0.05 mm to 0.15 mm, and the average pore size is 2 μm to 60 μm. The thickness of the titanium mesh is 0.05 mm to 0.5 mm, and the mesh size is between 0.2 mm × 1 mm and 6 mm × 10 mm.

3. The method for preparing a porous transport layer of an anode for producing hydrogen by electrolysis of water by PEM according to claim 1, wherein: The mass ratio of anhydrous ethanol, polyvinyl butyral and titanium powder in the slurry in step 2 is 10-100:1:10-100, and the particle size of the titanium powder does not exceed 30 μm.

4. The method for preparing a porous transport layer of an anode for producing hydrogen by electrolysis of water by PEM according to claim 1, wherein: During the stacking in step 3, the number of titanium mesh layers after spraying the slurry is not less than 2.

5. The method for preparing a porous transport layer of an anode for producing hydrogen by electrolysis of water by PEM according to claim 1, wherein: The temperature of the vacuum diffusion welding in step 3 is 1000℃~1300℃, the time is 1h~15h, and the vacuum degree does not exceed 1×10 -2 Pa, pressure is 0.2MPa~3MPa.

6. A porous transport layer for an anode of PEM water electrolysis for hydrogen production prepared by the method according to any one of claims 1 to 5, characterized in that: The total thickness of the anode porous transport layer is 0.2mm~2mm, the average pore size is 2µm~50µm, and the air permeability is 20m 3 / h·kPa·m 2 ~4000m 3 / h·kPa·m 2 , the tensile strength is 100MPa~500MPa.