Water electrolysis membrane electrode manufacturing method for improving bubble management
By using titanium-plated iron mesh and modified polytetrafluoroethylene during the membrane electrode fabrication process to form a microstructure, the problem of poor bubble management was solved, and the electrochemical performance and stability of the membrane electrode were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-22
- Publication Date
- 2026-04-14
AI Technical Summary
In existing proton exchange membrane electrolyzers, poor bubble management leads to increased voltage loss and reduced catalyst-water contact, thus affecting membrane electrode performance.
In the preparation of membrane electrode, titanium-plated iron mesh is used as a carrier. The titanium-plated iron mesh is treated with modified polytetrafluoroethylene to form a microstructure on the surface of the proton exchange membrane. Combined with the vacuum degassing treatment of the catalyst slurry, the uniformity of the catalyst layer and the effective management of bubbles are ensured.
It improves the performance of membrane electrode under high current density, reduces the risk of bubble accumulation to isolate the catalyst, maintains the integrity and stability of the catalyst layer, and enhances the bubble management capability of the electrode.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of fuel cell technology and relates to a method for fabricating a water electrolysis membrane electrode that improves bubble management. Background Technology
[0002] In a proton exchange membrane (PEM) electrolyzer, the membrane electrode assembly (MEA) is one of the key factors determining the performance of PEM water electrolysis. It mainly consists of a gas diffusion layer, a catalyst layer, and the PEM itself. Besides the high requirements for the PEM, gas diffusion layer, and catalyst, the proper structural assembly and the establishment of favorable interfacial effects significantly impact the electrochemical performance of the MEA.
[0003] In PEM water electrolysis, water molecules undergo oxidation at the anode, losing electrons to produce oxygen and protons. Electrons are then conducted to the cathode via an external circuit, while protons, under the influence of an electric field, are conducted through the proton exchange membrane to the cathode, where they undergo reduction to gain electrons and generate hydrogen. The resulting hydrogen and oxygen are collected and transported through the bipolar plates at the anode and cathode.
[0004] In this process, water is introduced from the anode, where a reaction occurs to produce oxygen. As the current density increases, the rate of gas production accelerates, and the voltage drop caused by the bubbles gradually intensifies. Bubble accumulation on the catalyst surface isolates the catalyst from water, reducing the effective active area. Simultaneously, the supersaturated oxygen surrounding the catalyst further reduces the reaction rate. Therefore, effective bubble management is crucial for improving the performance of PEM water electrolysis.
[0005] To enhance bubble management, adding microstructures and cavities to the smooth catalytic layer surface of the membrane electrode can promote the formation and release of bubbles. However, secondary processing of the already manufactured electrode (such as mold pressing) can cause certain damage to the membrane electrode and bring about the risk of breakage. Therefore, it is necessary to invent a new method to prepare the membrane electrode. Summary of the Invention
[0006] The purpose of this invention is to provide a method for fabricating a water electrolysis membrane electrode that improves bubble management. The prepared membrane electrode has a microstructure on its surface, strong bubble management capability, and high electrode performance under high electrical density.
[0007] The objective of this invention can be achieved through the following technical solutions: A method for fabricating a water electrolysis membrane electrode to improve bubble management, characterized in that the fabrication method includes the following steps: Preparation of catalyst slurry: 15–60 wt% catalyst, 20–30 wt% ionomer dispersion, 2–5 wt% dispersant, 1–3 wt% N-methylpyrrolidone, 20–35 wt% water, and 20–35 wt% alcohol are uniformly mixed by ultrasonication or ball milling. After thorough dispersion, the mixture is degassed by vacuum degassing to prepare a catalyst slurry. S2. Titanium-plated iron mesh treated with modified polytetrafluoroethylene: Polytetrafluoroethylene is dissolved in water, and anti-adhesion agent and surfactant are added. The mixture is ultrasonically dispersed evenly. The titanium-plated iron mesh is immersed in the polytetrafluoroethylene dispersion 2 to 3 times. After being taken out, it is dried and sintered at 300 to 350°C in air atmosphere to obtain a titanium-plated iron mesh wrapped with a modified polytetrafluoroethylene film. Place the proton exchange membrane on the workbench and completely cover the proton exchange membrane with a titanium-plated iron mesh wrapped with modified polytetrafluoroethylene. S3. Preparation of a catalyst layer on the surface of a proton exchange membrane: A magnetic force is applied under the workbench, and the weak magnetism of the titanium-plated iron mesh is used to fix the cathode / anode side of the proton exchange membrane on the workbench. The cathode and anode catalyst slurries are coated onto the proton exchange membrane by direct coating. The membrane is then dried in an oven at a temperature of 40–120 °C for 1–4 h to obtain a proton exchange membrane with a catalyst layer on its surface. S4. Fabrication of membrane electrode: After the catalyst layer is dried, the titanium-plated iron mesh is removed. Carbon paper is stacked on the cathode side of the proton exchange membrane that forms the catalyst layer, and titanium felt is stacked on the anode side. After being stacked neatly, the membrane electrode is placed in a hot pressing mold and hot-pressed to obtain the membrane electrode. The pressing temperature is 90-160 °C, the pressure is 10-40 bar, and the pressing time is 1-5 min.
[0008] As a preferred embodiment of the present invention, in step S1, the catalyst is one or more of Pt / C, PtNi / C, PtFe / C, PtCu / C, Ir, IrOx, IrRuOx, Ir / TiO2, and Ir / Nb2O5.
[0009] As a preferred embodiment of the present invention, in step S1, the ionomer dispersion contains 5-25% by mass; the ionomer is one or more of Nafion resin and anionic polymer A201.
[0010] As a preferred embodiment of the present invention, in step S1, the ultrasonic treatment is a low-temperature ultrasonic dispersion treatment, wherein the temperature of the low-temperature ultrasonic dispersion treatment is 0-25 ℃ and the time is 10-60 min; the ball milling speed is 100-800 rpm and the ball milling time is 1-24 h.
[0011] As a preferred technical solution of the present invention, in step S1, the ionomer dispersion is prepared by mixing the ionomer with solvent ethanol and water, and then stirring and ultrasonicating with a tip.
[0012] As a preferred embodiment of the present invention, in step S1, the alcohol is one of isopropanol, n-propanol, and ethanol.
[0013] As a preferred embodiment of the present invention, in step S2, the surfactant is one of perfluoropolyether and its ammonium salt, perfluoropolyether carboxylic acid and its ammonium salt, and perfluorobutylsulfonic acid.
[0014] As a preferred technical solution of the present invention, in step S2, the addition ratio of polytetrafluoroethylene, anhydrous ethanol, anti-adhesion agent and surfactant is: 10-30 wt%: 30-50 wt%: 1-3 wt%: 10-20 wt%.
[0015] As a preferred embodiment of the present invention, in step S2, the anti-adhesion agent is oleic acid amide, paraffin wax, or diatomaceous earth.
[0016] In this invention, the catalyst slurry is prepared as an anode or cathode catalyst slurry.
[0017] The beneficial effects of this invention are: (1) By using titanium-plated iron mesh to make the electrode surface have microstructure, it can promote bubble overflow and enhance bubble management. Moreover, the titanium-plated iron mesh does not cause secondary damage to the membrane electrode and can reduce the risk of leakage.
[0018] (2) The weak magnetic adsorption of the titanium-plated iron mesh plays a role in fixing the membrane and has no toxicity risk to the PEMWE membrane electrode system. Furthermore, the moderate magnetic properties will not cause strong shear risk during the membrane electrode preparation process. This can alleviate membrane swelling and deformation during production and prevent the introduction of poisoned metal ions. At the same time, by hydrophobically treating the titanium-plated iron mesh and adding polytetrafluoroethylene and anti-sticking agents, the slurry does not wet the surface-hydrophobically treated titanium-plated iron mesh. When the iron mesh is removed, the catalyst layer structure remains intact on the membrane. Meanwhile, the catalyst adhering to the titanium-plated iron mesh is easy to clean and recover.
[0019] (3) Add a dispersant to the catalyst slurry to avoid the subsequent agglomeration of ionomer aggregates with the catalyst, and obtain a uniformly dispersed and stable catalyst slurry. Remove the bubbles in the catalyst slurry by vacuum degassing to avoid the generation of bubbles in the catalyst layer during the direct coating process. Attached Figure Description
[0020] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.
[0021] Figure 1 A schematic diagram of a catalyst layer formed by coating a catalyst slurry onto a proton exchange membrane; Figure 2 The polarization curves are those of the membrane electrodes prepared in Examples 1-2 and the comparative examples after being assembled into an electrolytic cell. Detailed Implementation
[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.
[0023] Example 1 Preparation of catalyst slurry: Nafion resin was dissolved in ethanol and water and subjected to high-precision ultrasonic treatment to prepare a 10% ionomer dispersion. A cathode catalyst slurry was prepared by ultrasonic treatment of 45 wt% Pt / C catalyst with a metal content of 40%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 10 wt% water, and 20 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. An anode catalyst slurry was prepared by ultrasonic treatment of 30 wt% IrO2 catalyst with a metal content of 78 wt%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 15 wt% water, and 30 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. Titanium-plated iron mesh treated with modified polytetrafluoroethylene: 30 wt% of polytetrafluoroethylene was fully dissolved in 50 wt% of water, 2 wt% of anti-sticking agent and 18 wt% of surfactant were added, and the mixture was ultrasonically dispersed evenly. The titanium-plated iron mesh was immersed in the solution and repeatedly immersed 3 times. After being taken out, it was dried and sintered to obtain a titanium-plated iron mesh wrapped with a modified polytetrafluoroethylene film. Place the proton exchange membrane on the worktable and completely cover the anode side of the proton exchange membrane with a titanium-plated iron mesh wrapped with modified polytetrafluoroethylene. Preparation of a catalyst layer on the surface of a proton exchange membrane: A magnetic force was applied under the workbench, and the proton exchange membrane was fixed on the workbench by the weak magnetism of the titanium-plated iron mesh. The anode catalyst slurry was coated onto the proton exchange membrane by direct coating. The membrane was dried at 80 °C for 4 h to obtain a proton exchange membrane with an anode catalyst layer on its surface. A titanium-plated iron mesh was used as the backing of a proton exchange membrane with an anode catalyst layer and dried at 80 °C for 4 h to obtain a proton exchange membrane with a cathode catalyst layer on its surface. Fabrication of membrane electrodes: Titanium-plated iron mesh with the anode catalyst layer removed is used. Carbon paper is stacked on the cathode side of the proton exchange membrane forming the catalyst layer, and titanium felt is stacked on the anode side. After being stacked neatly, the membrane electrode is placed in a hot press mold and hot-pressed to strengthen it, thereby obtaining the membrane electrode. The pressurization temperature is 150℃, the pressure is 20 bar, and the pressurization time is 5 min.
[0024] Example 2 Preparation of catalyst slurry: Nafion resin was dissolved in ethanol and subjected to high-precision ultrasonic treatment to prepare a 10% ionomer dispersion. A cathode catalyst slurry was prepared by ultrasonic treatment of 45 wt% Pt / C catalyst with a metal content of 40%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 10 wt% water, and 20 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. An anode catalyst slurry was prepared by ultrasonic treatment of 30 wt% IrO2 catalyst with a metal content of 78 wt%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 15 wt% water, and 30 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. Titanium-plated iron mesh treated with modified polytetrafluoroethylene: 30 wt% of polytetrafluoroethylene was fully dissolved in 50 wt% of water, 2 wt% of anti-sticking agent and 18 wt% of surfactant were added, and the mixture was ultrasonically dispersed evenly. The titanium-plated iron mesh was immersed in the solution three times, and then dried and sintered to obtain a titanium-plated iron mesh wrapped with a modified polytetrafluoroethylene film. Place the proton exchange membrane on the worktable and completely cover the anode / cathode side of the proton exchange membrane with a titanium-plated iron mesh wrapped with modified polytetrafluoroethylene. Preparation of a catalyst layer on the surface of a proton exchange membrane: A magnetic force was applied under the workbench, and the proton exchange membrane was fixed on the workbench by the weak magnetism of the titanium-plated iron mesh. The anion / anode catalyst slurry was coated onto the proton exchange membrane by direct coating. The membrane was dried at 80 °C for 4 h to obtain a proton exchange membrane with anion / anode catalyst layers on the surface. Fabrication of membrane electrodes: Titanium-plated iron mesh with the anode / cathode catalyst layer removed was used. Carbon paper was stacked on the cathode side of the proton exchange membrane forming the catalyst layer, and titanium felt was stacked on the anode side. After being stacked neatly, the membrane electrode was placed in a hot press mold and hot-pressed to strengthen it, thereby obtaining the membrane electrode. The pressurization temperature was 150 °C, the pressure was 20 bar, and the pressurization time was 5 min.
[0025] Comparative Example Preparation of catalyst slurry: Nafion resin was dissolved in ethanol and subjected to high-precision ultrasonic treatment to prepare a 10% ionomer dispersion. A cathode catalyst slurry was prepared by ultrasonic treatment of 45 wt% Pt / C catalyst with a metal content of 40%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 10 wt% water, and 20 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. An anode catalyst slurry was prepared by ultrasonic treatment of 30 wt% IrO2 catalyst with a metal content of 78 wt%, 20 wt% ionomer dispersion, 3 wt% dispersant, 2 wt% N-methylpyrrolidone, 15 wt% water, and 30 wt% isopropanol at 0–25 °C for 30 min. The cathode catalyst slurry was then degassed by vacuum degassing. Preparation of a catalyst layer on the surface of a proton exchange membrane: The proton exchange membrane was placed on the worktable, and the cathode and anode catalyst slurries were coated on both sides of the proton exchange membrane by direct coating. The membrane was then dried at 80 °C for 4 h to obtain a dry proton exchange membrane with a catalyst layer on its surface. Fabrication of membrane electrodes: Carbon paper is stacked on the cathode side of the proton exchange membrane forming the catalyst layer, and titanium felt is stacked on the anode side. After being stacked neatly, the membrane electrode is placed in a hot pressing mold and reinforced by hot pressing. The pressing temperature is 150 °C, the pressure is 20 bar, and the pressing time is 5 min.
[0026] The polarization curves of the proton exchange membrane water electrolysis devices in Examples 1-2 and the comparative example were measured during hydrogen production operation, and the polarization curves are shown below. Figure 2 As shown, from Figure 2 The battery polarization curves show that the comparative example, lacking titanium-plated iron mesh treatment and therefore without surface microstructures, exhibits the steepest polarization curve slope. The example with iron mesh treatment and surface microstructures shows a lower polarization curve slope, indicating better battery performance. The membrane electrode prepared in this invention, due to its surface microstructure, possesses stronger bubble management capabilities, resulting in superior battery performance.
[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A method for fabricating a water electrolysis membrane electrode to improve bubble management, characterized in that: The preparation method includes the following steps: S1. Preparation of catalyst slurry: 15–60 wt% catalyst, 20–30 wt% ionomer dispersion, 2–5 wt% dispersant, 1–3 wt% N-methylpyrrolidone, 20–35 wt% water, and 20–35 wt% alcohol are uniformly mixed by ultrasonication or ball milling. After thorough dispersion, the mixture is degassed by vacuum degassing to prepare a catalyst slurry. S2. Titanium-plated iron mesh treated with modified polytetrafluoroethylene: Polytetrafluoroethylene is dissolved in water, and anti-sticking agent and surfactant are added. The mixture is ultrasonically dispersed, and titanium-plated iron mesh is immersed in the polytetrafluoroethylene dispersion 2 to 3 times. After being taken out, it is dried and sintered at 300 to 350°C in air atmosphere to obtain titanium-plated iron mesh wrapped with modified polytetrafluoroethylene film. Place the proton exchange membrane on the workbench and completely cover the proton exchange membrane with a titanium-plated iron mesh wrapped in modified polytetrafluoroethylene. S3. Preparation of a catalyst layer on the surface of a proton exchange membrane: A magnetic force is applied under the workbench, and the weak magnetism of the titanium-plated iron mesh is used to fix the cathode / anode side of the proton exchange membrane on the workbench. The cathode / anode catalyst slurry is coated onto the proton exchange membrane by direct coating. The membrane is dried in an environment with a temperature of 40-120 °C for 1-4 h to obtain a proton exchange membrane with a catalyst layer on the surface. S4. Fabrication of membrane electrode: After the catalyst layer is dried, the titanium-plated iron mesh is removed. Carbon paper is stacked on the cathode side of the proton exchange membrane that forms the catalyst layer, and titanium felt is stacked on the anode side. After being stacked neatly, the membrane electrode is placed in a hot pressing mold and hot-pressed to obtain the membrane electrode. The pressing temperature is 90-160℃, the pressure is 10-40 bar, and the pressing time is 1-5 min.
2. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S1, the catalyst is Pt / C, PtNi / C, PtFe / C, PtCu / C, Ir, or IrO. x 、IrRuO x One or more of Ir / TiO2 and Ir / Nb2O5.
3. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S1, the ionomer dispersion contains 5-25% by mass; the ionomer is one or more of Nafion resin and anionic polymer A201.
4. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S1, the ultrasonic treatment is a low-temperature ultrasonic dispersion treatment, the temperature of which is 0-25 ℃ and the time is 10-60 min; the ball milling speed is 100-800 rpm and the ball milling time is 1-24 h.
5. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S1, the ionomer dispersion is prepared by mixing the ionomer with solvents ethanol and water, and then thoroughly stirring and ultrasonicating.
6. The method for fabricating a water electrolysis membrane electrode to improve anode bubble management according to claim 1, characterized in that: In step S1, the alcohol is one of isopropanol, n-propanol, and ethanol.
7. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S2, the surfactant is one of perfluoropolyether and its ammonium salt, perfluoropolyether carboxylic acid and its ammonium salt, and perfluorobutylsulfonic acid.
8. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S2, the addition ratio of polytetrafluoroethylene, water, anti-adhesion agent and surfactant is: 10-30 wt%: 30-50 wt%: 1-3 wt%: 10-20 wt%.
9. The method for fabricating a water electrolysis membrane electrode to improve bubble management according to claim 1, characterized in that: In step S2, the anti-adhesion agent is oleamide, paraffin, or diatomaceous earth.
10. The preparation of the catalyst slurry according to any one of claims 1-9 is the preparation of an anode or cathode catalyst slurry.