Anion exchange membrane water electrolysis membrane electrode cooperatively constructed by hydrophilic / hydrophobic materials and water electrolysis cell
By introducing hydrophilic and hydrophobic materials into the anion exchange membrane water electrolytic membrane electrode, a gradient wettability is formed, which solves the problem of efficient ion conduction and gas discharge, improves the stability of the electrode and hydrogen yield, and reduces energy consumption.
Patent Information
- Application Number
- CN202510666211.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-22
- Publication Date
- 2025-07-18
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In the prior art, the anion exchange membrane water electrolytic membrane electrode is difficult to take into account both the efficient ion conduction and the efficient gas discharge. The overly hydrophilic catalyst layer causes gas blockage, and the overly hydrophobic design is not conducive to the uniform supply of ion transfer and water, affecting long-term efficient operation.
Anion exchange membrane water electrolytic membrane electrode constructed with collaborative construction of hydrophilic/hydrophobic materials, by introducing hydrophilic and hydrophobic materials into the catalyst layer, combined with introducing hydrophilic and hydrophobic materials into the gas diffusion layer, forming gradient wettability, and achieving efficient coordination between moisture management and gas diffusion.
It achieves efficient ion conduction and gas diffusion, inhibits liquid water reverse osmosis, improves the long-term stability of the electrode and hydrogen yield, and reduces energy consumption and anode overpotential.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of hydrogen production by water electrolysis, and particularly relates to an anion exchange membrane water electrolysis membrane electrode and a water electrolyzer jointly constructed by hydrophilic / hydrophobic materials. Background Art
[0002] Anion exchange membrane water electrolysis (AEMWE) is considered to be one of the important routes for large-scale clean hydrogen production due to its characteristics of low cost, high energy efficiency, and the ability to utilize non-precious metal catalysts. In AEMWE, the structure of the membrane electrode plays a decisive role in multiple performances such as water management, ion conduction, and gas diffusion.
[0003] In the prior art, most membrane electrode structures are difficult to balance between "efficient ion conduction" and "efficient gas discharge". A catalyst layer that is too hydrophilic often leads to gas blockage and a reduction in the interfacial active area, while a fully hydrophobic design is not conducive to ion transfer and uniform water supply. Traditional gas diffusion layers (GDLs) either cause backflow of the electrolyte due to excessive hydrophilicity or hinder water supply due to excessive hydrophobicity, both of which are not conducive to the long-term efficient operation of AEMWE. Summary of the Invention
[0004] In order to solve the problems in the related art, the embodiments of the present disclosure provide an anion exchange membrane water electrolysis membrane electrode and a water electrolyzer jointly constructed by hydrophilic / hydrophobic materials.
[0005] In a first aspect, the embodiments of the present disclosure provide an anion exchange membrane water electrolysis membrane electrode jointly constructed by hydrophilic / hydrophobic materials, characterized in that the water electrolysis membrane electrode includes a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer that are sequentially stacked; both the cathode catalyst layer and the anode catalyst layer are added with hydrophilic components and hydrophobic components; both the anode gas diffusion layer and the cathode gas diffusion layer are added with hydrophilic components and hydrophobic components.
[0006] In a possible implementation manner, the hydrophilic components of the cathode catalyst layer and the anode catalyst include hydroxylated carbon nanotubes; the hydrophobic components of the cathode catalyst layer and the anode catalyst include polytetrafluoroethylene.
[0007] In a possible implementation manner, the hydrophilic components of the anode gas diffusion layer and the cathode gas diffusion layer include aminated carbon fibers; the hydrophobic components of the anode gas diffusion layer and the cathode gas diffusion layer include ethylene tetrafluoroethylene copolymer.
[0008] In one possible implementation, the hydrophilic components of the cathode catalyst layer and the anode catalyst include at least one of the following: graphene oxide, functionalized carbon black or carbon paper containing carboxyl, hydroxyl or sulfonic acid groups, polyvinyl alcohol or its copolymers, chitosan, gelatin and other natural polymer materials, polyacrylamide, hyperbranched polymers such as polyethyleneimine.
[0009] In a possible implementation, the hydrophobic components of the cathode catalyst layer and the anode catalyst include at least one of the following: polyvinylidene fluoride, silane-modified nanoparticles, fusible fluororesin, silicone rubber particles, super-hydrophobic graphene or graphene nanosheets.
[0010] In one possible implementation, the hydrophilic components of the anode gas diffusion layer and the cathode gas diffusion layer include at least one of the following: porous alumina or silicon oxide, modified PEDOT:PSS conductive polymer, hydrophilic groups formed by heat treatment after injection of sulfonated polymer solution, carboxyl- or sulfonic acid-functionalized carbon fiber cloth or non-woven fabric.
[0011] In one possible implementation, the hydrophobic components of the anode gas diffusion layer and the cathode gas diffusion layer include at least one of the following: hydrophobically treated metal non-woven fabric (such as fluorosilane surface treatment), super-hydrophobic carbon nanotubes, a triple-proof coating (such as a chlorinated surfactant), polytetrafluoroethylene expanded micropowder, and polyetheretherketone powder.
[0012] In a possible implementation, the amount of the hydrophilic component added is equal to the amount of the hydrophobic component added.
[0013] In a possible implementation, the amount of the hydrophilic component added is higher or lower than the amount of the hydrophobic component added.
[0014] In a second aspect, an embodiment of the present disclosure provides a water electrolysis cell, comprising the water electrolysis membrane electrode as described in any one of the first aspects.
[0015] The technical effects provided by the embodiments of the present disclosure may include the following beneficial effects: According to the technical solution provided by the embodiments of the present disclosure, an anion exchange membrane electrolysis membrane electrode is constructed by hydrophilic / hydrophobic materials. The electrolysis membrane electrode includes a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer that are stacked in sequence; both hydrophilic components and hydrophobic components are added to the cathode catalyst layer and the anode catalyst layer; both hydrophilic components and hydrophobic components are added to the anode gas diffusion layer and the cathode gas diffusion layer. Through the above technical solution, by simultaneously introducing a hydrophilic material (such as hydroxylated carbon nanotubes) and a hydrophobic material (such as polytetrafluoroethylene) into the catalyst layer, the balance of ion conduction and gas diffusion is achieved, and by simultaneously introducing a hydrophilic material (such as amino-functionalized carbon fiber) and a hydrophobic material (such as FEP) into the gas diffusion layer, the construction of gradient wettability and the inhibition of liquid water back osmosis are realized. This solution achieves efficient coordination of water management and gas diffusion.
[0016] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. Detailed implementation manners
[0017] The present invention will be further described below by way of examples. However, it can be understood that these specific examples will not limit the scope of the present invention in any way. It should be noted that unless otherwise specified, the raw materials used in the following examples are all commercially available products. Examples
[0018] This experimental group provides a highly stable electrolysis membrane electrode, which includes an anode gas diffusion layer, an anode catalyst layer, an anion exchange membrane, a cathode catalyst layer, and a cathode gas diffusion layer that are stacked in sequence.
[0019] Both hydrophilic components and hydrophobic components are added to the anode catalyst layer and the cathode catalyst layer. The hydrophilic component can be, for example, hydroxylated carbon nanotubes, with an addition amount of 5 wt%, and the hydrophobic component can be, for example, polytetrafluoroethylene (PTFE), with an addition amount of 10 wt%.
[0020] In the pores of the anode gas diffusion layer and the cathode gas diffusion layer, gradient blending of hydrophilic components and hydrophobic components can be adopted. The hydrophilic component can be, for example, amino-functionalized carbon fiber, and the hydrophobic component can be, for example, fluorinated ethylene propylene copolymer (FEP), such as 15 wt% of amino-functionalized carbon fiber and 25 wt% of FEP content.
[0021] In this embodiment, the content of the hydrophilic component is higher than that of the hydrophobic component.
[0022] Optional hydrophilic materials for the catalyst layer include: graphene oxide, (GO) functionalized carbon black or carbon paper containing carboxyl, hydroxyl or sulfonic acid groups, polyvinyl alcohol (PVA) or its copolymers, chitosan, gelatin and other natural polymer materials, polyacrylamide (PAM), hyperbranched polymers such as polyethyleneimine (PEI).
[0023] Optional hydrophobic materials for the catalyst layer include: polyvinylidene fluoride (PVDF), silane-modified nanoparticles (such as trifluoropropylsilane-modified silica), fusible chlorine resin (such as ETFE), silicone rubber particles, super-hydrophobic graphene or graphite nanosheets.
[0024] The optional hydrophilic materials for the gas diffusion layer include: porous alumina or silicon oxide, modified PEDOT:PSS conductive polymer, hydrophilic groups formed by heat treatment after injecting sulfonated polymer solution, carboxyl- or sulfonic acid-functionalized carbon fiber cloth or non-woven fabric.
[0025] Optional hydrophobic materials for the gas diffusion layer include: hydrophobically treated metal non-woven fabrics (such as fluorosilane surface treatment), super-hydrophobic carbon nanotubes, triple-proof coatings (such as fluorinated surface agents), expanded polytetrafluoroethylene powder, and polyetheretherketone (PEEK) powder.
[0026] Preparation method of water electrolysis membrane electrode structure: 1. Preparation of catalyst layer: a) Preparation of composite catalyst ink Weigh the components according to the predetermined mass ratio of the catalyst, the hydrophilic material (e.g., hydroxylated carbon nanotubes, graphene oxide, PVA, etc.), the hydrophobic material (e.g., PTFE emulsion, PVDF micropowder, etc.), and the ion conductor (e.g., AEM ionomer);
[0027] Adding each component to a proper amount of solvent (such as a mixture of isopropanol and water), and ultrasonically dispersing for 30-60 minutes to obtain a uniformly dispersed catalyst composite ink;
[0028] If necessary, a binder (such as a cationic ionomer for a spray AEM system) is added.
[0029] b) Coating film The catalyst ink prepared in the previous step is evenly coated on the surface of an anion exchange membrane (AEM) by spraying (air-brush), blade coating or spin coating, or is first prepared on an inert substrate (such as PTFE membrane) and then transferred to the AEM membrane;
[0030] The catalyst layer loading is controlled within a preset range (e.g., 0.22-mg / cm²) and dried at room temperature to 2 hours to promote solvent evaporation.
[0031] c) Heat pressing / pressing For improving the interface contact, hot pressing (e.g., pressure 300 psi for 3 - 5 min) can be used for assembly to ensure the tight combination of the catalyst layer and the AEM.
[0032] 2. Preparation and treatment of the gas diffusion layer: a) Selection and modification Substrates such as carbon paper, carbon cloth, and metal foam are selected and modified hydrophilically or hydrophobically by chemical or physical means. For example: dropping or impregnating a hydrophobic emulsion containing FEP, PTFE, etc. onto the surface of the carbon paper and heat - treating to form a film; Preparing a porous layer with amino - functionalized carbon fibers, or wet - coating / spraying in increasing amounts on the inner side of the gas diffusion layer.
[0033] b) Constructing a wetting gradient Spraying or sandwich - distributing a high - proportion hydrophilic material (such as 10 - 30 wt% GO or functionalized carbon fibers) on the side close to the catalyst layer, Gradually increasing the proportion of hydrophobic materials (such as 15 - 40 wt% PTFE or FEP) in the outer layer to form a hydrophilic - neutral - hydrophobic gradient layer by layer; When conditions permit, vacuum - assisted deposition, step - by - step impregnation, or 3D printing can be used to construct the gradient layer by layer.
[0034] c) Drying and shaping The composite gas diffusion layer is dried at 60 - 120 °C for 2 hours for assembly use.
[0035] 3. Overall assembly of the membrane - electrode assembly (MEA): Align the prepared membrane / catalyst layer and the gas diffusion layer longitudinally and clamp them between the flow - field plates of the electrolytic cell.
[0036] Ensure tight overall contact without obvious gaps through mechanical pressing or re - hot pressing.
[0037] For end - plate sealing and interface protection, a high - strength hydrophilic / hydrophobic sealant or anti - leakage membrane can be compounded in areas such as the edge of the MEA. Example 2
[0038] This example refers to the preparation method provided in Example 1 to prepare a water electrolysis membrane - electrode. The difference between this example and Example 1 is that the content of hydrophilic components (such as hydroxylated carbon nanotubes, amino - functionalized carbon fibers) is equal to that of hydrophobic components (such as PTFE, FEP), for example, hydrophilic accounts for 15 wt% and hydrophobic accounts for 15 wt%. Example 3
[0039] This example refers to the preparation method provided in Example 1 to prepare a water electrolysis membrane electrode. The difference between this example and Example 1 is that the content of hydrophilic components (such as hydroxylated carbon nanotubes, amino-functionalized carbon fibers) is lower than that of hydrophobic components (such as PTFE, FEP). For example, the hydrophilic component accounts for 25 wt% and the hydrophobic component accounts for 15 wt%. Comparative Example 1: This comparative example provides a water electrolysis membrane electrode, which includes a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer stacked in sequence.
[0040] Only traditional hydrophilic carbon carriers and catalysts (excluding hydroxylated carbon nanotubes and PTFE) are used in the catalyst layer, and only commercial carbon paper is used in the gas diffusion layer.
[0041] Comparative Example 2: This comparative example provides a water electrolysis membrane electrode, which includes a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer stacked in sequence.
[0042] Only hydroxylated carbon nanotubes (5 wt%) are added to the catalyst layer, without PTFE; the gas diffusion layer is amino-functionalized carbon fiber carbon paper.
[0043] Comparative Example 3: This comparative example provides a water electrolysis membrane electrode, which includes a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer stacked in sequence.
[0044] Only PTFE (10 wt%) is added to the catalyst layer; the gas diffusion layer is FEP composite carbon paper.
[0045] Test results: The test objects and test results in this test example are shown in Tables 1 - 4.
[0046] Table 1: Comparison of current density change and retention rate
[0047] Description of test method Under the conditions of constant voltage (2.0 V) and constant temperature (25 °C) in 1 M KOH electrolyte, each assembled membrane electrode structure is continuously energized in a 5 cm² active area electrolytic cell for 8 hours. Constant voltage polarization is used, and the steady-state current density at the 10th minute of initial power-on and the current density at the end of 8-hour operation are recorded respectively. The current retention rate is calculated as the current density at the end of 8 h divided by the initial current density.
[0048] The current density of the patent solution (Example 2) is not only significantly higher than that of the other groups under initial and long-term (8 hours) operation, but also has a retention rate of nearly 98%, which is much higher than the conventional one (81.3%), indicating that the structure significantly improves the electrode's ability to output long-term stable output.
[0049] Table 2: Comparison of hydrogen production per unit area
[0050] Test method description: At a constant current density (900mA / cm²), a gas flow meter (such as a wet gas meter or a mass flow meter) is used to monitor and accumulate the volume of hydrogen evolution gas online. After seal correction, it is converted to the number of moles of hydrogen under standard conditions. Divided by the active area, the hydrogen yield per unit area per unit time is obtained, and the increase is the increase value relative to the comparison group.
[0051] This patented solution effectively improves the hydrogen yield, and the hydrogen production efficiency is much higher than that of single-hydrophilic / hydrophobic or traditional membrane electrode, which directly shows that the coordinated management of water and gas can achieve higher gas release efficiency and energy conversion rate, providing greater advantages for actual industrial expansion.
[0052] Table 3: Comparison of water reverse osmosis and interface management
[0053] Test Method Description The mass of liquid water passing through the AEM to the cathode side per hour (in mg / h) was calculated by mass monitoring (quantitative weighing of the solution flowing into / out of the electrode chamber) and ion chromatography. The suitability of the interface water content was evaluated by electrochemical impedance spectroscopy and interface microscopic observation of the amount of adsorbed water, supplemented by observation of flooding / drying-up.
[0054] The water reverse osmosis of the solution of the present invention (Example 2) is optimal, the moisture management range is optimal, and the phenomenon of water flooding or drying up at unfavorable interfaces is effectively reduced, which is a direct embodiment of the gradient wetting design of this patent.
[0055] Table 4: Comparison of anode overpotential and energy consumption
[0056] Test Method Description The three-electrode system is used for testing, with the anode as the working electrode and the cathode in combination with the reference electrode (such as Hg / HgO), and the anode polarization potential at 2.0V is recorded. The energy consumption is converted into the energy consumption per unit volume of hydrogen (energy consumption of cubic meter of hydrogen under standard conditions, kWh / Nm³H2) according to the corresponding steady-state voltage and current and hydrogen production. All test data are the average of multiple measurements.
[0057] The anodic overpotential is significantly reduced and the energy consumption is decreased, which is a direct result of the improved reaction kinetics under the optimization of the multi-component microenvironment. This means that the energy consumption for hydrogen production decreases significantly under the same conditions, saving costs for the system operation.
[0058] According to the above test results, it can be seen that the hydrophilic / hydrophobic ratio of 1:1 (Example 2) has the best comprehensive performance and is optimal in all key data such as high current density, retention rate, lowest energy consumption, and most stable interface management (suitable water content range, least flooding or drying).
[0059] When the hydrophilic component is in excess of the hydrophobic component (Example 1), slight flooding is likely to occur, but the retention rate is higher than that of only hydrophilic; when the hydrophilic component is less than the hydrophobic component (3:1, Example 3), some areas tend to dry out, but the overall performance is still better than that of only hydrophobic.
[0060] The anion exchange membrane electrolysis membrane electrode co-constructed by the hydrophilic / hydrophobic materials provided in this application realizes the balance of ion conduction and gas diffusion by simultaneously introducing a hydrophilic material (such as hydroxylated carbon nanotubes) and a hydrophobic material (such as PTFE) into the catalyst layer, and realizes the construction of gradient wettability and inhibits the reverse osmosis of liquid water by simultaneously introducing a hydrophilic material (such as amino-functionalized carbon fiber) and a hydrophobic material (such as FEP) into the gas diffusion layer. This solution realizes the efficient coordination of water management and gas diffusion.
[0061] The above description is only the preferred embodiments of the present disclosure and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present disclosure.
Claims
1. An anion exchange membrane water electrolysis membrane electrode co-constructed by hydrophilic / hydrophobic materials, characterized in that, The water electrolysis membrane electrode comprises a cathode gas diffusion layer, a cathode catalyst layer, an anion exchange membrane, an anode catalyst layer, and an anode gas diffusion layer which are stacked in sequence; the cathode catalyst layer and the anode catalyst are added with hydrophilic components and hydrophobic components at the same time; the anode gas diffusion layer and the cathode gas diffusion layer are added with hydrophilic components and hydrophobic components at the same time.
2. The anion exchange membrane electrolytic membrane electrode according to claim 1, characterized in that, The hydrophilic components of the cathode catalyst layer and the anode catalyst include hydroxylated carbon nanotubes; and the hydrophobic components of the cathode catalyst layer and the anode catalyst include polytetrafluoroethylene.
3. The anion exchange membrane electrolytic membrane electrode according to claim 1, wherein The hydrophilic components of the anode gas diffusion layer and the cathode gas diffusion layer include amino carbon fibers; and the hydrophobic components of the anode gas diffusion layer and the cathode gas diffusion layer include fluorinated ethylene propylene copolymer.
4. The anion exchange membrane electrolysis membrane electrode according to claim 1, characterized in that, The hydrophilic components of the cathode catalyst layer and the anode catalyst include at least one of the following: graphene oxide, functionalized carbon black or carbon paper containing carboxyl, hydroxyl or sulfonic acid groups, polyvinyl alcohol or its copolymer, chitosan, gelatin and other natural polymer materials, polyacrylamide (PAM), hyperbranched polymers such as polyethyleneimine.
5. The anion exchange membrane electrolytic membrane electrode according to claim 1, characterized in that, The hydrophobic components of the cathode catalyst layer and the anode catalyst include at least one of the following: polyvinylidene fluoride, silane-modified nanoparticles, fusible fluororesin (, silicone rubber particles, super-hydrophobic graphene or graphene nanosheets.
6. The anion exchange membrane water electrolysis membrane electrode according to claim 1, wherein, The hydrophilic components of the anode gas diffusion layer and the cathode gas diffusion layer include at least one of the following: porous aluminum oxide or silicon oxide, modified PEDOT:PSS conductive polymer, hydrophilic groups formed by heat treatment after injecting sulfonated polymer solution, and carboxyl- and sulfonic acid-containing functionalized carbon fiber cloth or non-woven fabric.
7. The anion exchange membrane electrolytic membrane electrode according to claim 1, wherein The hydrophobic components of the anode gas diffusion layer and the cathode gas diffusion layer include at least one of the following: hydrophobically treated metal non-woven fabric, super-hydrophobic carbon nanotubes, a three-proof coating, polytetrafluoroethylene expanded powder, and polyetheretherketone (PEEK) powder.
8. The anion exchange membrane electrolytic membrane electrode according to claim 1, wherein The amount of the hydrophilic component added is equal to the amount of the hydrophobic component added.
9. The anion exchange membrane electrolytic membrane electrode according to claim 1, characterized in that, The amount of the hydrophilic component added is higher or lower than the amount of the hydrophobic component added.
10. A water electrolysis cell, characterized in that, It comprises the anion exchange membrane water electrolysis membrane electrode as described in any one of claims 1 to 9.