Membrane electrode assembly and device for producing hydrogen through water electrolysis
By introducing a buffer layer into the membrane electrode assembly, the anode catalytic layer is protected, and the catalytic layer damage caused by titanium fiber felt is solved, which extends the life of the membrane electrode and improves the stability and performance of the electrolytic cell.
Patent Information
- Application Number
- CN202420348814.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-23
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-02-23
AI Technical Summary
In the proton exchange membrane electrolytic device, when the titanium fiber felt is used as the anode porous transport layer, the catalytic layer is easily squeezed under pressure, resulting in damage to the catalytic layer and affecting the life and performance of the membrane electrode.
A membrane electrode assembly including anode porous transport layer, a proton conductive membrane and a cathode porous transport layer was designed. A buffer layer was introduced into the anode porous transport layer, and a plurality of conductive microporous layers were sintered. The thickness of the buffer layer was 50-200μm. , the porosity is 20%-50%, to protect the anode catalytic layer and avoid extrusion damage.
By setting the buffer layer, extrusion damage of the anode catalytic layer is avoided, the service life of the membrane electrode is extended, the stability and performance of the electrolytic cell are improved, and the production cost is reduced.
Smart Images
Figure CN222160388U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of water electrolysis hydrogen production, and more specifically, to a membrane electrode assembly and a device for water electrolysis hydrogen production. Background Art
[0002] Hydrogen is considered to be the most promising energy carrier due to its cleanliness, high efficiency, abundant sources and renewable characteristics. Major countries in the world are actively developing hydrogen energy in order to cope with global climate change and energy crisis.
[0003] For the development and utilization of hydrogen energy, the preparation of hydrogen is the starting point and focus. At present, the methods for preparing hydrogen include hydrogen production from methanol decomposition, hydrogen production from ammonia decomposition, biohydrogen production, solar hydrogen production, fossil fuel hydrogen production and water electrolysis. Among them, water electrolysis is considered to be a very promising method for preparing hydrogen. In particular, the proton exchange membrane water electrolysis device uses renewable clean energy to convert water into hydrogen through the proton exchange membrane water electrolysis device, and the converted hydrogen is used as an energy carrier or raw material for human production activities. Renewable energy such as wind and light is used in the preparation process, which has less impact on the environment and can also significantly reduce the emission of greenhouse gases and toxic and hazardous substances.
[0004] In addition, compared with other current water electrolysis technologies, proton exchange membrane water electrolysis devices produce hydrogen more efficiently and with higher hydrogen purity. They are also well adaptable to renewable clean energy with volatility and intermittency, and are currently the focus of development in countries around the world.
[0005] In the proton exchange membrane water electrolysis device, the membrane electrode assembly is the core component of the water electrolysis device, which is mainly composed of the proton membrane located in the middle, the cathodic and cation catalyst layers located on both sides of the proton membrane in close contact with the proton membrane, and the porous transport layer located outside the catalyst layer. The catalyst layer on one side of the proton exchange membrane is the anode catalyst, and the one on the other side is the cathode catalyst. When the water electrolysis device is working, water produces and releases oxygen under the catalysis of the anode catalyst, and produces and releases hydrogen under the catalysis of the cathode catalyst.
[0006] In the membrane electrode assembly, the combination of the catalyst coated membrane (CCM) composed of the catalyst and the proton membrane and the cathode and anode porous transport layers (PTL) on both sides of the CCM has a significant impact on the final performance and life of the electrolyzer. The most commonly used cathode PTL is carbon paper with a microporous layer. The anode PTL is mainly titanium fiber felt or titanium fiber felt coated with corrosion-resistant materials on the surface. The titanium fiber felt used in this anode PTL has a large pore size, high porosity, and low cost. However, when the CCM and titanium fiber felt are assembled into an electrolyzer, under the action of pressure, the titanium fiber felt will be in close contact with the surface of the catalyst layer of the CCM, and the titanium fibers of the titanium fiber felt will squeeze the catalyst layer, resulting in obvious indentations and even cracks in the catalyst layer. In particular, after the electrolytic water tank is passed through water, the proton membrane will swell significantly, which will aggravate the damage to the catalyst layer caused by this extrusion. This damage will have a great impact on the life of the CCM. In order to solve this problem and improve the performance and life of the CCM, it is necessary to design a new membrane electrode assembly and structure. Utility Model Content
[0007] The utility model aims to overcome at least one defect (deficiency) of the above-mentioned prior art, and provides a membrane electrode assembly and a device for producing hydrogen by water electrolysis, so as to reduce the damage of the anode catalyst layer.
[0008] One object of the utility model is to provide a membrane electrode assembly for hydrogen production by water electrolysis, comprising an anode porous transport layer, a CCM and a cathode porous transport layer connected in sequence, the CCM comprising a proton conducting membrane, an anode catalyst layer and a cathode catalyst layer, the anode catalyst layer and the cathode catalyst layer being coated on both sides of the proton conducting membrane, the anode porous transport layer comprising a connected substrate layer and a buffer layer, the buffer layer comprising a plurality of conductive microporous layers, the conductive microporous layers being sintered by a plurality of particle units, the particle units being metal particles or oxide particles, the buffer layer having a thickness of 50-200 μm, and the conductive microporous layer having a porosity of 20%-50%.
[0009] In the present technical solution, the buffer layer of the porous transport layer plays a buffering and barrier role. Through its setting, when assembling the electrolytic cell, under the action of pressure, even if the porous transport layer and the anode catalyst layer are in close contact, the anode catalyst layer will not be squeezed, thereby avoiding the material of the base layer of the porous transport layer from damaging the anode catalyst layer, thereby extending the service life of the membrane electrode, improving the stability of the electrolytic cell, and reducing production costs.
[0010] If the thickness of the buffer layer is too thick, it will affect the mass transfer of the membrane electrode. If it is too thin, it will limit its barrier buffering effect. Therefore, appropriate thickness setting and porosity coordination can protect the anode catalyst layer and avoid cracks while ensuring normal mass transfer of the membrane electrode.
[0011] Furthermore, the thickness of the anode porous transport layer is 0.1-1 mm, the thickness of the base layer is 70-800 μm, and the porosity of the base layer is 50%-75%.
[0012] Furthermore, the metal particles are titanium, and the metal oxide particles are tin oxide.
[0013] In the present technical solution, both titanium and tin oxide have good electronic conductivity and can be easily made into porous layered structures.
[0014] Furthermore, the particle size of the particle unit of each layer of the conductive microporous layer differs from its average particle size by 0 to 5 μm. In the present technical solution, the particle size of each layer of the conductive microporous layer differs from the average particle size of the particle unit of each layer of the conductive microporous layer by 0 to 5 μm. It can be understood that the particle unit size of each layer of the conductive microporous layer is the same or similar.
[0015] Furthermore, the buffer layer includes at least two conductive microporous layers, and the average particle size of the particle units of the conductive microporous layers gradually decreases from the outside to the inside; the pore size and porosity of the conductive microporous layers gradually decrease from the outside to the inside.
[0016] In the present technical solution, the outer side refers to the side close to the substrate layer, and the inner side refers to the side close to the anode catalyst layer. The gradient distribution of the particle size, pore size and porosity is beneficial to the transfer of reactant water and product oxygen, and can also improve the contact degree between the catalyst layer and the porous transport layer, improve the utilization rate of the catalyst layer, and ultimately improve the performance of the entire membrane electrode assembly.
[0017] Furthermore, the thickness of the proton conducting membrane is 8-200 μm.
[0018] Furthermore, the catalyst of the anode catalyst layer is an iridium-based catalyst, and the iridium content of the anode catalyst layer is 50-2000 μg / cm 2 .
[0019] Furthermore, the catalyst of the cathode catalyst layer is a platinum-based catalyst, and the platinum content of the cathode catalyst layer is 10-1000 μg / cm 2 .
[0020] Furthermore, the anode catalyst layer and the cathode catalyst layer are coated on both sides of the proton conducting membrane by one or more methods of hot pressing transfer, spraying or direct coating.
[0021] Another object of the present utility model is to provide a water electrolysis hydrogen production device, comprising an electrolyzer and any of the above-mentioned membrane electrode assemblies, wherein the membrane electrode assemblies are assembled in series, bipolar plates are provided on both sides of the membrane electrode assemblies, the outer side of the anode porous transport layer is the oxygen plate of the bipolar plate, the outer side of the cathode porous transport layer is the hydrogen plate of the bipolar plate, and end plates are provided on both sides of the electrolyzer.
[0022] Compared with the prior art, the beneficial effects of the utility model are:
[0023] (1) By setting up the buffer layer, when assembling the electrolytic cell, under the action of pressure, even if the porous transport layer and the anode catalyst layer are in close contact, the anode catalyst layer will not be squeezed, thereby avoiding damage to the anode catalyst layer, thereby extending the service life of the membrane electrode, improving the stability of the electrolytic cell, and reducing production costs.
[0024] (2) The gradient distribution of the particle size, pore size and porosity is beneficial to the transfer of reactant water and product oxygen, and can also improve the contact degree between the catalyst layer and the porous transport layer, improve the utilization rate of the catalyst layer, and ultimately improve the performance of the entire membrane electrode assembly.
[0025] (3) By properly setting the thickness and porosity of the buffer layer, the anode catalyst layer can be protected and cracks can be avoided while ensuring normal mass transfer of the membrane electrode. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a schematic diagram of the structure of the membrane electrode assembly of Example 1.
[0027] Figure 2 SEM images of the anode porous transport layer of Example 1 and Comparative Example 1: (A) surface SEM image of the anode porous transport layer of Example 1; (B) surface SEM image of the anode porous transport layer of Comparative Example 1; (C) cross-sectional SEM image of the anode porous transport layer of Example 1; (D) cross-sectional SEM image of the anode porous transport layer of Comparative Example 1.
[0028] Figure 3 SEM images of the anode catalyst layer of Example 1 and Comparative Example 1 before and after the initial water electrolysis performance test: (A) SEM morphology image of the anode catalyst layer before the initial water electrolysis performance test; (B) SEM morphology image of the anode catalyst layer of the membrane electrode assembly of Comparative Example 1 after the initial water electrolysis performance test; (C) SEM morphology image of the anode catalyst layer of the membrane electrode assembly of Example 1 after the initial water electrolysis performance test.
[0029] Figure 4 This is a graph showing the initial performance test results of water electrolysis of the membrane electrode assemblies of Example 1 and Comparative Example 1.
[0030] Reference numerals: substrate layer 1 , conductive microporous layer 2 , buffer layer 21 , anode catalyst layer 3 , proton conducting membrane 4 , cathode catalyst layer 5 , cathode porous transport layer 6 . DETAILED DESCRIPTION
[0031] The drawings of the present invention are only used for illustrative purposes and cannot be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.
[0032] Example 1
[0033] like Figure 1 As shown, this embodiment provides a membrane electrode assembly for hydrogen production by water electrolysis, wherein the membrane electrode assembly includes an anode porous transport layer, a CCM and a cathode porous transport layer 6 connected in sequence, the CCM includes a proton conducting membrane 4, an anode catalyst layer 3 and a cathode catalyst layer 5, the anode catalyst layer 3 and the cathode catalyst layer 5 are coated on both sides of the proton conducting membrane 4, the anode porous transport layer includes a connected base layer 1 and a buffer layer 21, the buffer layer 21 includes a plurality of conductive microporous layers 2, the conductive microporous layer 2 is sintered by a plurality of particle units, the particle units are metal particles or oxide particles, the thickness of the buffer layer 21 is 50-200 μm, preferably 80-150 μm, the porosity of the conductive microporous layer 2 is 20%-50%, preferably 25%-35%.
[0034] The metal particles are preferably titanium, and the metal oxide particles are preferably tin oxide. Both titanium and tin oxide have good electronic conductivity and are convenient to be made into porous layered structures. The base layer 1 is preferably sintered titanium fiber. The proton conducting membrane 4 is a homogeneous proton membrane or an enhanced proton membrane. The material of the cathode porous transport layer 6 is preferably carbon paper with a microporous layer.
[0035] The buffer layer 21 plays a buffering and barrier role. Through its setting, when assembling the electrolytic cell, under the action of pressure, even if the base layer 1 and the anode catalyst layer 3 are in close contact, the material of the base layer 1 will not squeeze the anode catalyst layer 3, thereby avoiding the material of the base layer 1 from damaging the anode catalyst layer 3, thereby extending the service life of the membrane electrode, improving the stability of the electrolytic cell, and reducing production costs.
[0036] If the thickness of the buffer layer 21 is too thick, it will affect the mass transfer of the membrane electrode. If it is too thin, it will limit its barrier and buffering effect. Therefore, appropriate thickness setting and porosity coordination can protect the anode catalyst layer 3 and avoid cracks while ensuring normal mass transfer of the membrane electrode.
[0037] The thickness of the anode porous transport layer is 0.1-1 mm, the thickness of the base layer 1 is 70-800 μm, and the porosity of the base layer 1 is 50%-75%.
[0038] The particle size of the particle unit of each layer of the conductive microporous layer 2 differs from the average particle size of the layer by 0 to 5 μm, for example, by 0 μm, 2 μm or 5 μm, etc. The buffer layer 21 may include one or more layers of the conductive microporous layer 2. In this embodiment, it is preferably a plurality of layers. The conductive microporous layers 2 are stacked and connected, and are arranged on the inner side of the base layer 1. The average particle size of the particle unit of the conductive microporous layer 2 gradually decreases from the outer side to the inner side; the pore size and porosity of the conductive microporous layer 2 gradually decrease from the outer side to the inner side.
[0039] The outer side refers to the side close to the substrate layer 1, and the inner side refers to the side close to the anode catalyst layer 3. The gradient distribution of the particle size, pore size and porosity is beneficial to the transfer of reactant water and product oxygen, and can also improve the contact degree between the catalyst layer and the porous transport layer, improve the utilization rate of the catalyst layer, and ultimately improve the performance of the entire membrane electrode assembly.
[0040] The thickness of the proton conducting membrane 4 is 8-200 μm. In this embodiment, it is preferably an enhanced proton membrane of 80 μm. The catalyst of the anode catalyst layer 3 is an iridium-based catalyst, and the iridium content of the anode catalyst layer 3 is 50-2000 μg / cm 2 In this embodiment, the anode catalyst layer 3 includes an iridium-based catalyst and an ion polymer, and the iridium loading of the anode catalyst layer 3 is 1 mg / cm 2 .
[0041] The catalyst of the cathode catalyst layer 5 is a platinum-based catalyst, and the platinum content of the cathode catalyst layer 5 is 10-1000 μg / cm 2 In this embodiment, the cathode catalyst layer 5 includes a platinum-based catalyst and an ion polymer, and the platinum loading of the cathode catalyst layer is 0.35 mg / cm 2 .
[0042] The anode catalyst layer 3 and the cathode catalyst layer 5 are coated on both sides of the proton conducting membrane 4 by one or more methods including hot pressing transfer, spraying or direct coating.
[0043] Example 2
[0044] The present embodiment provides a water electrolysis hydrogen production device, comprising an electrolyzer and the membrane electrode assembly provided in Example 1, wherein the membrane electrode assembly is assembled in series, bipolar plates are provided on both sides of the membrane electrode assembly, the outer side of the anode porous transport layer is the oxygen plate of the bipolar plate, the outer side of the cathode porous transport layer is the hydrogen plate of the bipolar plate, and end plates are provided on both sides of the electrolyzer.
[0045] Comparative Example 1
[0046] This comparative example provides a membrane electrode assembly for producing hydrogen by water electrolysis, and its structure is different from that of the membrane electrode assembly of Example 1 in that the anode porous transport layer does not include a buffer layer.
[0047] The SEM images of the anode porous transport layer of Example 1 and Comparative Example 1 are as follows: Figure 2 As shown, Figure 2 A is a surface SEM image of the anode porous transport layer of Example 1; Figure 2 B is a surface SEM image of the anode porous transport layer of Comparative Example 1; Figure 2 C is a cross-sectional SEM image of the anode porous transport layer of Example 1; Figure 2 D is a cross-sectional SEM image of the anode porous transport layer of Comparative Example 1. Figure 2 A and Figure 2 B shows that the porous surface of the anode of the utility model is smoother, which can reduce the damage to the anode catalyst layer under pressure.
[0048] The SEM images of the anode catalyst layer of Example 1 and Comparative Example 1 before and after the initial performance test of water electrolysis are as follows: Figure 3 As shown: Figure 3 A is the SEM morphology of the anode catalyst layer before the initial water electrolysis performance test; Figure 3 B is a SEM morphology of the anode catalyst layer of the membrane electrode assembly of comparative example 1 after the initial performance test of water electrolysis; Figure 3 C is a SEM morphology of the anode catalyst layer of the membrane electrode assembly of Example 1 after the initial performance test of water electrolysis. Figure 3 A and Figure 3 C shows that the anode catalyst layer remains intact after the membrane electrode assembly of the utility model is assembled and tested; Figure 3 B and Figure 3 C shows that, through the provision of the anode porous transport layer of the utility model, the anode catalyst layer is prevented from being damaged by the anode porous transport layer under pressure.
[0049] The membrane electrode assemblies of Example 1 and Comparative Example 1 were respectively used to form electrolyzers, and the initial performance test of water electrolysis was carried out at 60°C. The results are as follows: Figure 4 As shown in the test result diagram, it can be seen that the structural arrangement of the membrane electrode assembly of the utility model is conducive to improving the performance of the membrane electrode.
[0050] Obviously, the above embodiments of the utility model are only examples for clearly explaining the technical solution of the utility model, and are not intended to limit the specific implementation methods of the utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the utility model shall be included in the protection scope of the claims of the utility model.
Claims
1. A membrane electrode assembly for hydrogen production by water electrolysis, comprising an anode porous transport layer, a CCM and a cathode porous transport layer connected in sequence, wherein the CCM comprises a proton conducting membrane, an anode catalyst layer and a cathode catalyst layer, wherein the anode catalyst layer and the cathode catalyst layer are coated on both sides of the proton conducting membrane, characterized in that: The anode porous transport layer includes a connected base layer and a buffer layer, the buffer layer includes a plurality of conductive microporous layers, the conductive microporous layers are sintered by a plurality of particle units, the particle units are metal particles or oxide particles, the buffer layer has a thickness of 50-200 μm, and the conductive microporous layer has a porosity of 20%-50%.
2. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 1, characterized in that: The thickness of the anode porous transport layer is 0.1-1 mm, the thickness of the base layer is 70-800 μm, and the porosity of the base layer is 50%-75%.
3. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 1, characterized in that: The metal particles are titanium, and the oxide particles are tin oxide.
4. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 1, characterized in that: The particle size of the particle unit of each conductive microporous layer differs from its average particle size by 0 to 5 μm.
5. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 4, characterized in that: The buffer layer comprises at least two conductive microporous layers, the average particle size of the particle units of the conductive microporous layers gradually decreases from the outside to the inside; the pore size and porosity of the conductive microporous layers gradually decrease from the outside to the inside.
6. The membrane electrode assembly for producing hydrogen by water electrolysis according to any one of claims 1 to 5, characterized in that: The thickness of the proton conducting membrane is 8-200 μm.
7. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 6, characterized in that: The catalyst of the anode catalyst layer is an iridium-based catalyst, and the iridium content of the anode catalyst layer is 50-2000 μg / cm 2 .
8. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 6, characterized in that: The catalyst of the cathode catalyst layer is a platinum-based catalyst, and the platinum content of the cathode catalyst layer is 10-1000 μg / cm 2 .
9. The membrane electrode assembly for producing hydrogen by water electrolysis according to claim 6, characterized in that: The anode catalyst layer and the cathode catalyst layer are coated on both sides of the proton conducting membrane by one or more methods of hot pressing transfer, spraying or direct coating.
10. A water electrolysis hydrogen production device, characterized in that: It comprises an electrolytic cell and a membrane electrode assembly as described in any one of claims 1 to 9, wherein the membrane electrode assemblies are assembled in series, bipolar plates are provided on both sides of the membrane electrode assembly, the outer side of the anode porous transport layer is an oxygen plate of the bipolar plate, the outer side of the cathode porous transport layer is a hydrogen plate of the bipolar plate, and end plates are provided on both sides of the electrolytic cell.