Water electrolysis hydrogen production device and membrane electrode assembly and exchange membrane thereof
By using a double-layer thin film structure of ion solvation membrane and anion exchange membrane in the water electrolysis hydrogen production device, the stability and mechanical strength problems of the anion exchange membrane are solved, the high conductivity and long life water electrolysis hydrogen production effect is achieved, and the commercial application of the technology is promoted.
Patent Information
- Application Number
- CN202510620336.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-09-23
AI Technical Summary
The insufficient stability and low mechanical strength of anion exchange membranes lead to reduced conductivity, affecting ion transmission efficiency, and making them prone to thinning and rupture, which limits the commercial development of anion exchange membrane water electrolysis hydrogen production technology.
A double-layer film structure is adopted, including an ion solvation membrane and an anion exchange membrane with a thickness of 80-120μm. The ion solvation membrane is located between the anode catalyst layer and the anion exchange membrane. By introducing a dense membrane with Lewis acid functional groups, the conductivity and stability are enhanced to avoid the degradation of the ion exchange side chain.
The electrochemical performance of the water electrolysis hydrogen production device has been improved, the alkaline stability and mechanical stability have been enhanced, the service life of the membrane has been extended, the equipment maintenance cost has been reduced, and the commercialization process of the anion exchange membrane water electrolysis hydrogen production technology has been promoted.
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Figure CN120683515A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of hydrogen production by electrolysis of water, and in particular to a hydrogen production device by electrolysis of water, and its membrane electrode assembly and exchange membrane. Background Art
[0002] Anion exchange membrane (AEM) is a polymer membrane containing alkaline active groups that is selectively permeable to anions. In the field of hydrogen production by water electrolysis, anion exchange membrane water electrolysis (AEMWE) technology combines the advantages of low-cost electrodes for traditional alkaline water electrolysis with the high current density and rapid response of proton membrane water electrolysis. It operates under weakly alkaline conditions and can use non-precious metal catalysts and inexpensive metal bipolar plates, reducing catalyst costs and energy consumption. Furthermore, AEMWE technology exhibits excellent dynamic response characteristics, enabling rapid start and stop to adapt to fluctuations in renewable energy. Furthermore, AEMWE can use pure water or low-concentration alkaline solutions as electrolytes, avoiding the problem of strong corrosion and making the entire water electrolysis device leak-free, compact, and easy to handle. Compared to traditional alkaline water electrolysis, anion exchange membrane water electrolysis can operate at lower voltages, improving the energy conversion efficiency of the electrolysis process. It is also more tolerant to impurities and has a wider range of applications.
[0003] The membrane electrode assembly (MEA) is the core component of an anion exchange membrane (AEM) water electrolysis hydrogen production electrolyzer, with the anion exchange membrane being its most critical component. This MEA typically comprises a diffusion layer, a catalytic layer, and an anion exchange membrane. The anion exchange membrane is a selective diaphragm typically made of a polymer with positively charged functional groups. Because it can selectively transport anions while isolating gases such as oxygen and hydrogen, anion exchange membranes are a common diaphragm for water electrolysis under alkaline conditions. However, the lack of stability and low mechanical strength of anion exchange membranes are key factors hindering their large-scale application. In an anodic environment, the side chains of the anion exchange membrane are easily oxidized and scission occurs. This scission reduces the membrane's conductivity and affects ion transport efficiency. Over time, the membrane may become thinner or even rupture, ultimately rendering the electrolyzer unusable. This not only increases equipment maintenance costs but also limits the large-scale commercialization of AEM water electrolysis hydrogen production technology. Summary of the Invention
[0004] Various aspects of the present application provide a water electrolysis hydrogen production device, a membrane electrode assembly, and an exchange membrane thereof, to solve one or more of the above-mentioned problems.
[0005] The present application provides an electrolytic water hydrogen production device, comprising: an anode end plate, an anode current collector, a cathode current collector, a cathode end plate, and a membrane electrode assembly disposed between the anode current collector and the cathode current collector. The membrane electrode assembly comprises an anode diffusion layer, an anode catalyst layer, an exchange membrane, a cathode catalyst layer, and a cathode diffusion layer arranged in sequence from the anode current collector toward the cathode current collector, wherein the exchange membrane comprises an ion solvation membrane and an anion exchange membrane in contact with each other, the ion solvation membrane being interposed between the anode catalyst layer and the anion exchange membrane, and the exchange membrane having a thickness of 80-120 μm.
[0006] In some embodiments of the present application, the anion exchange membrane is selected from one of polyarylether anion exchange membranes, aromatic ether bond-free anion exchange membranes, and other membranes that can selectively conduct anions.
[0007] In some embodiments of the present application, the ion solvation membrane is a dense membrane containing Lewis acid functional groups.
[0008] The present application also provides a membrane electrode assembly of a water electrolysis hydrogen production device, which includes an anode diffusion layer, an anode catalyst layer, an exchange membrane, a cathode catalyst layer and a cathode diffusion layer, wherein the exchange membrane includes an ion solvation membrane and an anion exchange membrane in contact with each other, the ion solvation membrane is between the anode catalyst layer and the anion exchange membrane, and the thickness of the exchange membrane is 80-120 μm.
[0009] The present application also provides an exchange membrane for a water electrolysis hydrogen production device, which has a thickness of 80-120 μm, and the exchange membrane includes an ion solvation membrane and an anion exchange membrane in contact with each other.
[0010] In an embodiment of the present application, the exchange membrane of the water electrolysis hydrogen production device includes an ion solvation membrane and an anion exchange membrane in contact with each other. Since the two layers of film are tightly bonded, only a very small gap exists under the action of swelling. When the total thickness of the double-layer film is equal to the thickness of the single-layer anion exchange membrane of the existing water electrolysis device, it not only has better electrochemical properties, but also has properties such as alkaline stability and mechanical stability, thereby solving the problems of the existing single-layer anion exchange membrane, such as low chemical stability and conductivity, and easy thinning and rupture. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0012] Figure 1 Schematic diagram of a plan view of a water electrolysis hydrogen production device according to an embodiment of the present application.
[0013] Figure 2 for Figure 1 A simplified structural diagram of .
[0014] Figure 3 This is an electrochemical performance diagram of an embodiment of the present application.
[0015] Figure 4 This is a scanning electron microscope (SEM) image of the exchange membrane of the embodiment of the present application.
[0016] Figure 5 It is a plan view of an existing water electrolysis hydrogen production device. DETAILED DESCRIPTION
[0017] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0018] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.
[0019] See also Figure 1 and Figure 2The present application provides an embodiment of a water electrolysis hydrogen production device 1, which includes an anode end plate 10, an anode current collector 20, a cathode current collector 30, a cathode end plate 40, and a membrane electrode assembly 50, wherein the anode current collector 20, the cathode current collector 30, and the membrane electrode assembly 50 are sandwiched between the anode end plate 10 and the cathode end plate 40. A water inlet and a water outlet are provided on the anode end plate 10, and a water outlet is provided on the cathode end plate 40. The water inlet is used to allow the flow of electrolyte stock (e.g., 30% potassium hydroxide (KOH)), the water outlet is used to allow the oxygen-rich electrolyte to flow out after the hydrogen production reaction is completed, and the water outlet is used to allow the hydrogen-rich electrolyte to flow out after the hydrogen production reaction is completed. The anode current collector 20 is located on one side of the anode end plate 10, the cathode current collector 30 is located on one side of the cathode end plate 40, the membrane electrode assembly 50 is arranged between the anode current collector 20 and the cathode current collector 30, and a bipolar plate 60 is arranged between two adjacent membrane electrode assemblies 50 among the multiple membrane electrode assemblies 50.
[0020] like Figure 2 As shown, in the water electrolysis hydrogen production device 1 provided in the embodiment of the present application, the membrane electrode assembly 50 includes an anode diffusion layer 510, an anode catalyst layer 520, an exchange membrane 530, a cathode catalyst layer 540 and a cathode diffusion layer 550, which are arranged in sequence from the anode current collector 20 to the cathode current collector 30, so that the anode diffusion layer 510 corresponds to the anode current collector 20, the cathode diffusion layer 550 corresponds to the cathode current collector 30, and the exchange membrane 530 is interposed between the anode catalyst layer 520 and the cathode catalyst layer 540.
[0021] Wherein, the exchange membrane 530 includes an ion solvating membrane (ISM) 531 and an anion exchange membrane 532 in contact with each other, and the thickness of the exchange membrane 530 is 80-120 μm, that is, the sum of the thickness of the ion solvating membrane 531 and the thickness of the anion exchange membrane 532 is 80-120 μm. For example, in some embodiments of the present application, the ratio of the thickness of the ion solvating membrane 531 to the thickness of the anion exchange membrane 532 is 1:1, 1:3 or 2:1, for example, the thickness of the ion solvating membrane 531 is 20-30 μm, and the thickness of the anion exchange membrane 532 is 60-90 μm. In other words, the thickness of the ion solvating membrane 531 and the thickness of the anion exchange membrane 532 can be configured according to different requirements, such as the concentration of the alkaline electrolyte.
[0022] It is worth noting that although the exchange membrane 530 in the embodiment of the present application is in the form of a multilayer thin film, its total thickness is only 80-120 μm, which is almost or equivalent to the thickness of a single layer of an anion exchange membrane in an existing anion exchange membrane water electrolysis hydrogen production device. Therefore, the electrochemical performance exhibited by the exchange membrane 530 in the embodiment of the present application in the water electrolysis hydrogen production device 1 can be almost consistent with the electrochemical performance of a single layer membrane in an existing water electrolysis hydrogen production device. At the same time, compared with the single-layer anion exchange membrane in the existing water electrolysis hydrogen production device, in the exchange membrane 530 of the embodiment of the present application, the composition of the ion solvation membrane 531 is mainly based on polymers such as polybenzimidazole (PBI), and its ion conductivity is enhanced by introducing hydrophilic side chains (such as sulfonic acid groups) or compounding with other functional materials, so that the exchange membrane 530 can provide a higher ion conductivity through the ion solvation membrane 531. Moreover, since the ion solvation membrane 531 does not have ion exchange side chains, the degradation of ionic groups or polymer main chain structures is avoided, and thus the exchange membrane 530 can also be provided with good alkali stability, mechanical stability and electrochemical stability. The anion exchange membrane 532 can be, but is not limited to, a polyarylether anion exchange membrane, an anion exchange membrane without an aromatic ether bond, and other membranes that can selectively conduct anions, etc., which provide the exchange membrane 530 with properties such as high current density, fast response, long life, and low-cost electrode materials, thereby enabling the exchange membrane 530 of the present application to have the advantages of high conductivity, high chemical stability, and the membrane is not easy to rupture, which helps to promote the development of anion electrolysis water hydrogen production technology.
[0023] Furthermore, in an embodiment of the present application, the ion solvation membrane may be, but is not limited to, a dense membrane containing Lewis acid functional groups. These functional groups can solvate KOH and adsorb a large amount of electrolyte to form an ion transmission channel. Its composition is mainly based on polymers such as polybenzimidazole (PBI), and its ion conductivity is enhanced by introducing hydrophilic side chains (such as sulfonic acid groups) or compounding with other functional materials, so that the exchange membrane can provide a higher ion conductivity through the ion solvation membrane. And because the ion solvation membrane does not have ion exchange side chains, it avoids the degradation phenomenon of ionic groups or polymer main chain structures, and thus can also provide an exchange membrane with good alkali stability, mechanical stability and electrochemical stability. Its stability stems from the following reasons: First, the electrostatic force between ions and solvent molecules is the main source of stability of the solvation membrane. The electrostatic attraction between ions with high charge density and polar solvent molecules is stronger, and they can be tightly combined together; secondly, the physical properties of the solvent molecules themselves (such as polarity, dielectric constant) also have an important influence on stability. Polar solvents can better shield the electrostatic repulsion between ions, enhancing the stability of ion solvation membranes. Furthermore, the solvation membrane may further enhance stability through secondary forces such as hydrogen bonding. From a chemical perspective, the stability of the solvation membrane is closely related to the intrinsic properties of the ions (such as ionic radius and charge). Smaller ionic radius and higher charge make the electrostatic interactions between ions and solvent molecules more concentrated and intense. Therefore, the stability of ion solvation membranes is the result of the combined effects of the electrostatic interactions between ions and solvent molecules, the physical properties of the solvent molecules, and the intrinsic properties of the ions. This stability determines the ions' solubility behavior in solution, their ability to migrate, and their activity in chemical reactions.
[0024] The molecular structure of the ion solvation membrane used in some embodiments of the present invention is shown in the following structural formula 1:
[0025]
[0026] It should be noted that this molecular structure is only used as an example and is not limited to this in other embodiments of the present application.
[0027] In the molecular structure of this ion solvation membrane, the positive charge K + The groups are adsorbed and pass through the hydrophilic micropores or channels of the membrane under the electric field or concentration gradient, and then release OH - On the other side of the membrane, the functional groups are detached and enter the target solution or participate in the electrode reaction to generate O2.
[0028] Since the ion solvation membrane transfers hydroxide ions as cations connected to the polymer main chain through ionic bonds and will not break due to oxidation, the ion solvation membrane has good stability and is not easily damaged during the operation of the electrolytic cell.
[0029] The following further describes some embodiments of the present application and the technical effects that can be achieved.
[0030] Please refer to Figure 2 In the electrolysis water hydrogen production device 1 provided in the exemplary embodiment of the present application, the exchange membrane 530 is formed by placing two ion solvation membranes 531 and anion exchange membranes 532 of the same size alternately side by side. For example, a commercially available 25 μm thick ion solvation membrane 531 and a 90 μm thick anion exchange membrane 532 are used, which are combined with each other by pressing or laminating. At the same time, an anode catalyst, such as NiFeO, is coated on the surface between the ion solvation membrane 531 and the anode diffusion layer 510. X , as the anode catalyst layer 520 , and a cathode catalyst, such as Pt / C, is coated on the surface between the anion exchange membrane 532 and the cathode diffusion layer 550 to serve as the cathode catalyst layer 540 .
[0031] The control group was Figure 5 In the existing water electrolysis hydrogen production device shown, the exchange membrane M adopts a commercially available 110 μm thick anion exchange membrane, and the other conditions are consistent with the embodiment of the present application.
[0032] In the test, the anode liquid supply method is adopted to fill the electrolyte between the anode end plate and the cathode end plate, and the performance test of water electrolysis hydrogen production is carried out. The embodiment of the present application uses 30% KOH solution as the electrolyte, while the existing AEM water electrolysis hydrogen production device usually uses 5% KOH solution as the electrolyte. Figure 3 As shown, under an environment where the hydrogen pressure is 3.0 MPa and the oxygen is at normal pressure, it can be seen from the relationship diagram between the measured current density and the electrolysis voltage that when the exchange membrane thickness is almost equal, the electrochemical performance of the water electrolysis hydrogen production device provided in the embodiment of the present application is better than that of the existing water electrolysis hydrogen production device.
[0033] Afterwards, after the electrolysis water hydrogen production device has been running for 1000 hours, the exchange membrane is further analyzed, including chemical and physical property analysis. First, except for thickness, other parameters of the anion exchange membrane used in the prior art and the exchange membrane used in the present application are consistent. As shown in Table 1 below, the original conductivity of the exchange membrane of the existing anion exchange membrane is identical to that of the present application. However, after the electrolysis water hydrogen production device has been running for 1000h (hour), the conductivity of the anion exchange membrane used in the prior art has obviously declined to 99.1mS / cm, while the conductivity of the exchange membrane used in the present application has not declined, and can also maintain at 100mS / cm the same as the original conductivity. It can be seen that the present application can improve the stability of the anion exchange membrane.
[0034] Table 1. Changes in membrane conductivity before and after operation
[0035] Membrane type Original conductivity Conductivity after 1000h operation Existing 100mS / cm 99.1mS / cm This application 100mS / cm 100mS / cm
[0036] like Figure 4 As shown, the physical properties of the exchange membrane of this application were then analyzed. The results showed that the anion exchange membrane was well protected during operation and no obvious oxidative dissolution occurred, making the overall structure of the exchange membrane have good oxidative stability and mechanical stability. Therefore, according to Table 1 and Figure 4 Test results show that the exchange membrane in the embodiment of the present application utilizes a thinner ion solvation membrane in conjunction with a thicker anion exchange membrane, with the ion solvation membrane positioned on the anode side. This allows 30% of the alkaline electrolyte entering the electrolytic cell from the anode side to be blocked by the ion solvation membrane, resulting in a concentration of less than 5% alkaline electrolyte that passes through the ion solvation membrane and reaches the anion exchange membrane interface, effectively preventing oxidation of the anion exchange membrane in the anode environment. Furthermore, the use of a 30% alkaline electrolyte ensures the conductivity of the ion solvation membrane and the overall performance of the electrolytic cell.
[0037] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.
Claims
1. A water electrolysis hydrogen production device, characterized in that: include: An anode end plate, an anode current collector, a cathode current collector, a cathode end plate, and a membrane electrode assembly arranged between the anode current collector and the cathode current collector, wherein the membrane electrode assembly includes an anode diffusion layer, an anode catalyst layer, an exchange membrane, a cathode catalyst layer, and a cathode diffusion layer arranged in sequence from the anode current collector toward the cathode current collector, wherein the exchange membrane includes an ion solvation membrane and an anion exchange membrane in contact with each other, the ion solvation membrane is between the anode catalyst layer and the anion exchange membrane, and the thickness of the exchange membrane is 80-120 μm.
2. The water electrolysis hydrogen production device according to claim 1, characterized in that: The anion exchange membrane is selected from a polyarylether anion exchange membrane, an anion exchange membrane without an aryl ether bond, and other membranes that can selectively conduct anions.
3. The water electrolysis hydrogen production device according to claim 1, characterized in that: The ion solvation membrane is a dense membrane containing Lewis acid functional groups.
4. A membrane electrode assembly for a water electrolysis hydrogen production device, characterized in that: include: An anode diffusion layer, an anode catalyst layer, an exchange membrane, a cathode catalyst layer and a cathode diffusion layer are arranged in sequence, wherein the exchange membrane includes an ion solvation membrane and an anion exchange membrane in contact with each other, the ion solvation membrane is between the anode catalyst layer and the anion exchange membrane, and the thickness of the exchange membrane is 80-120 μm.
5. The membrane electrode according to claim 3, characterized in that The anion exchange membrane is selected from a polyarylether anion exchange membrane, an anion exchange membrane without an aryl ether bond, and other membranes that can selectively conduct anions.
6. The membrane electrode according to claim 3, characterized in that The ion solvation membrane is a dense membrane containing Lewis acid functional groups.
7. An exchange membrane for a water electrolysis hydrogen production device, characterized in that: The exchange membrane has a thickness of 80-120 μm, and comprises an ion solvation membrane and an anion exchange membrane in contact with each other.
8. The exchange membrane according to claim 5, characterized in that The anion exchange membrane is selected from a polyarylether anion exchange membrane, an anion exchange membrane without an aryl ether bond, and other membranes that can selectively conduct anions.
9. The exchange membrane according to claim 5, characterized in that The ion solvation membrane is a dense membrane containing Lewis acid functional groups.