Gas diffusion electrode with gradient microporous layer as well as preparation method and application of gas diffusion electrode
By constructing a gas diffusion electrode with a gradient microporous layer on the electrode surface, the problem of gas product aggregation during water electrolysis for hydrogen production was solved, thereby improving the efficiency of water electrolysis for hydrogen production and reducing energy consumption. This has good economic value and application prospects.
Patent Information
- Application Number
- CN202511048471.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-07
AI Technical Summary
During the process of producing hydrogen by water electrolysis, gaseous products accumulate on the electrode surface to form a bubble layer, which prevents the active micro-points on the electrode surface from contacting the electrolyte. This reduces the effective reaction area on the electrode surface, resulting in a large overpotential, which severely limits the rate of water electrolysis and the efficiency of hydrogen production.
A gas diffusion electrode with a gradient microporous layer is designed. By constructing a scientifically reasonable hydrophobic gradient through multiple microporous sublayers with different porosities, the electrode's ability to remove gaseous products is enhanced, ensuring that bubbles quickly detach from the electrode surface and maintaining full contact between the electrolyte and the electrode.
It significantly improves the efficiency of hydrogen production by water electrolysis, reduces the shielding of electrodes by bubbles, lowers energy consumption, and has a simple preparation method that is easy to scale up for production. The raw materials are inexpensive and have broad market prospects.
Smart Images
Figure CN120905699A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of hydrogen production electrode preparation by water electrolysis, and particularly relates to a gas diffusion electrode with a gradient microporous layer, a preparation method and application thereof in hydrogen production by electrolysis, in particular, a gas diffusion electrode with a gradient hydrophobic microporous layer for hydrogen production by water electrolysis and a manufacturing process thereof. BACKGROUND
[0002] Energy crisis and environmental pollution problems have become a serious challenge facing the world. With the continuous consumption of traditional fossil energy, its reserves are decreasing, and in the combustion process, a large amount of carbon dioxide, sulfur oxides, nitrogen oxides and other pollutants are released, leading to global climate warming, acid rain and other environmental problems, which seriously threaten human survival and development. Under this background, countries are actively committed to the development of renewable energy and new energy storage technologies in order to achieve sustainable use of energy and protection of the environment. Hydrogen energy, as a promising green energy, has the advantages of high energy density, only water as combustion product, no pollution, etc., and is expected to effectively solve the problems of traditional energy depletion and environmental pollution. At the same time, hydrogen energy storage has the advantages of fast response, long storage time, and no geographical restrictions, providing a feasible solution to the volatility problem of renewable energy generation, which can smooth the output of renewable energy and improve the stability and reliability of the power grid.
[0003] Water electrolysis for hydrogen production is a hydrogen production process widely used in many fields such as chemical industry, energy storage and transportation. This process injects water electrolyte into an electrolytic cell with electricity, and uses electrical energy to decompose water into hydrogen and oxygen, without generating additional carbon emissions and pollution, making it a highly efficient and green hydrogen production method. However, in the water electrolysis reaction, if the gas products (hydrogen and oxygen) produced on the surface of the electrode cannot be removed in time, they will accumulate on the surface of the electrode to form a bubble layer, preventing the active micro-points on the surface of the electrode from contacting the electrolyte, resulting in a decrease in the effective reaction area of the electrode surface, which in turn causes a large overpotential, severely limiting the rate of water electrolysis reaction, reducing the efficiency of hydrogen production, and increasing the cost of hydrogen production. Therefore, improving the electrode's ability to remove gas products is a key issue in improving the efficiency of water electrolysis for hydrogen production.
[0004] In order to remove the gas products in time and improve the electrode reaction kinetics in the process of water electrolysis for hydrogen production, it is urgent to develop a new type of gas diffusion electrode. SUMMARY
[0005] In view of the above problems, the present application aims to provide a gas diffusion electrode with a gradient microporous layer, a preparation method and application thereof in hydrogen production by electrolysis. The seawater electrolysis electrode of the present application can effectively improve the electrode's ability to remove gas products and achieve sustained and stable high-efficiency water electrolysis for hydrogen production.
[0006] To achieve the above object, the present application provides the following technical solutions:
[0007] A gas diffusion electrode with a gradient microporous layer, comprising a substrate, a gradient microporous layer arranged on one side of the substrate, and a catalyst layer arranged on the side of the gradient microporous layer away from the substrate;
[0008] The gradient microporous layer is stacked by at least two microporous sub-layers with different porosities, and the porosity of the microporous sub-layers gradually increases along the direction from the substrate to the catalyst layer; each microporous sub-layer is composed of an electrically conductive carbon material and a binder, the electrically conductive carbon material is selected from at least one of carbon black, graphene, and carbon nanotubes, and the binder is selected from at least one of polytetrafluoroethylene and polyvinylidene fluoride.
[0009] Further, the difference in porosity between two adjacent microporous sub-layers in the gradient microporous layer is 5%-30%.
[0010] Further, the thickness of the microporous sub-layer is 10-200 microns, and the total thickness of the gradient microporous layer is 50-500 microns.
[0011] Further, the substrate is an electrically conductive porous material selected from at least one of carbon paper, carbon cloth, and metal foam; the catalyst layer comprises a catalyst and an electrically conductive carrier, the catalyst is selected from at least one of platinum, ruthenium, iridium, and alloys thereof, and the electrically conductive carrier is selected from at least one of carbon black, carbon nanotubes, and graphene.
[0012] A preparation method of a gas diffusion electrode with a gradient microporous layer, comprising the following steps:
[0013] Preparation of microporous sub-layer slurries with different porosities: mix the electrically conductive carbon material and the binder in different proportions in the solvent, and by adjusting the proportions of the electrically conductive carbon material and the binder, at least two microporous sub-layer slurries with different porosities are prepared; along the direction from the substrate to the catalyst layer, the proportion of the electrically conductive carbon material in the microporous sub-layer slurry used subsequently gradually increases;
[0014] Coating microporous sub-layer slurries on the substrate: place the substrate on the coating device, and in order of increasing porosity, coat the microporous sub-layer slurries with different porosities on one side of the substrate, and after drying, form a gradient microporous layer;
[0015] Preparation of a catalyst layer and compounding: mix the catalyst and the electrically conductive carrier in the solvent to prepare a catalyst layer slurry, coat the catalyst layer slurry on the side of the gradient microporous layer away from the substrate, and after drying, obtain a gas diffusion electrode with a gradient microporous layer.
[0016] Further, the solvent is selected from at least one of ethanol, isopropanol, N-methyl pyrrolidone; the drying temperature is 60-120 DEG C, and the drying time is 1-6 h.
[0017] Further, in the preparation of the microporous sub-layer slurry with different porosities, ultrasonic treatment or ball milling treatment is also used to uniformly disperse the components, the ultrasonic treatment power is 100-500 W, and the time is 0.5-2 h; the ball milling treatment speed is 200-800 r / min, and the time is 1-5 h.
[0018] Further, the method for coating the microporous sub-layer slurry and the catalytic layer slurry is selected from at least one of spraying, doctor blading and screen printing.
[0019] Further, the application of the gas diffusion electrode with the gradient microporous layer in a fuel cell.
[0020] Further, the fuel cell is selected from at least one of a proton exchange membrane fuel cell, an alkaline fuel cell, a molten carbonate fuel cell and a solid oxide fuel cell.
[0021] The present application has the following beneficial effects:
[0022] 1. The gas diffusion electrode with the gradient microporous layer provided by the present application has a scientific and reasonable hydrophobicity gradient constructed by multiple layers of microporous layers with different hydrophobicities, and the unique structure can significantly enhance the removal capacity of the electrode to the gas product, make the bubbles quickly separate from the electrode surface, greatly reduce the shielding of the electrode by the bubbles, make the electrolyte fully contact with the electrode, thereby effectively improving the efficiency of water electrolysis to produce hydrogen and reducing the energy consumption.
[0023] 2. The electrode preparation method is simple, does not require complex equipment and harsh conditions, is easy to scale up production, and can quickly realize large-scale manufacturing.
[0024] 3. The required raw materials are low in price and rich in reserves, can effectively control the production cost, provide a solid guarantee for large-scale production and industrial application, have extremely high economic value and broad market prospects. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 It is a preparation process schematic diagram of the gas diffusion electrode with the gradient microporous layer.
[0026] Figure 2 It is a scanning electron microscope (SEM) diagram of the gas diffusion electrode with the gradient microporous layer.
[0027] Figure 3 It is an energy dispersive spectrometer (EDS) diagram of the gas diffusion electrode with the gradient microporous layer about fluorine element.
[0028] Figure 4 Linear sweep voltammetry curve of the full cell for the gas diffusion electrode with gradient microporous layer of the present application.
[0029] Figure 5 Electrochemical impedance spectroscopy (EIS) curve of the gas diffusion electrode with gradient microporous layer of the present application.
[0030] Figure 6 Constant current test curve of the gas diffusion electrode with gradient microporous layer of the present application. DETAILED DESCRIPTION
[0031] For the purpose of promoting an understanding of the present application, the present application will be described in greater detail below. However, the present application can be realized in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the present application to those skilled in the art.
[0032] Unless otherwise defined, all technical and scientific terms used in this specification shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. The use of the terms "and / or" includes a combination of one or more of the associated listed items.
[0033] In the process of implementation, the gas diffusion electrode with gradient microporous layer of the present application is an electrode for water electrolysis to produce hydrogen.
[0034] The electrode for water electrolysis to produce hydrogen is prepared according to the following steps:
[0035] S1: Dissolve carbon black and polytetrafluoroethylene solution in acetone in different proportions, with the mass fraction of polytetrafluoroethylene being 5%-30%; stir the mixture slurry to obtain a uniform mixture slurry with different hydrophobic rates;
[0036] S2: In order of decreasing hydrophobic rate, load the uniform mixture slurry on the surface of carbon paper layer by layer by ultrasonic spraying; after each loading of the slurry, place the carbon paper substrate in an air environment and heat treat at 400-600°C for 2-5h to form a microporous layer, load 2-3 layers of microporous layer in total, with a loading of 1-2mg / cm 2 ;
[0037] S3: Dissolve carbon black and platinum / carbon-ruthenium dioxide powder in acetone to obtain a catalytic layer slurry, load the catalytic layer slurry on the surface of the electrode by ultrasonic spraying, and heat treat in an air environment at 400-600°C for 2-5h to form a catalytic layer.
[0038] Example 1
[0039] The electrode was prepared by ultrasonic spraying of the slurry to obtain a gradient microporous layer. Figure 1 ).
[0040] The electrode preparation process was as follows:
[0041] The carbon black and polytetrafluoroethylene solution were weighed and dissolved in acetone in different proportions, with the mass fraction of polytetrafluoroethylene solution being 10%, 20%, and 30%, respectively.
[0042] After ultrasonic dispersion in a water bath and stirring with a magnetic stirrer for 12 h, three uniform mixtures were obtained.
[0043] The slurry with a polytetrafluoroethylene solution mass fraction of 30% was loaded on the carbon paper substrate using ultrasonic coating, with a loading amount of 1.5 mg / cm 2 , and then was sent into a muffle furnace for heat treatment at 500°C for 4 h in an air atmosphere.
[0044] The above steps were repeated, and the slurry with a polytetrafluoroethylene solution mass fraction of 20% and 10% was sequentially loaded on the substrate and subjected to heat treatment to form a microporous layer with a three-layer hydrophobic gradient. The carbon black and platinum / carbon-ruthenium dioxide powder were dissolved in acetone to obtain a catalytic layer slurry, which was loaded on the electrode surface using ultrasonic spraying, and then was sent into a muffle furnace for heat treatment at 500°C for 4 h in an air atmosphere to form a catalytic layer.
[0045] The SEM image of the electrode is shown in Figure 2 , which clearly shows that the granular microporous layer is loaded on the carbon paper fibers of the electrode substrate, and the dense microporous layer on the surface provides a low-resistance, continuous, and uniform electron conduction path between the catalytic layer and the carbon paper substrate, effectively reducing the ohmic loss in the electrode.
[0046] The EDS image of the electrode with respect to fluorine is shown in Figure 3 , which shows the difference in fluorine element between the carbon paper substrate and the microporous layer containing polytetrafluoroethylene. The microporous layer slurry with different mass fractions of polytetrafluoroethylene forms a gradient hydrophobic microporous layer, which forms a gas transport driving force pointing to the direction of the carbon paper substrate, facilitating the replenishment of electrolyte and the effective detachment of bubbles, reducing the shielding of the electrode by bubbles.
[0047] In summary, a gas diffusion electrode with a gradient microporous layer was successfully synthesized.
[0048] In a 1M potassium hydroxide (KOH) electrolyte, the full-cell linear sweep voltammetry curve is shown in Figure 4The results are shown in Figure 6. It can be seen that the gas diffusion electrode with gradient microporous layer has greater current density at the same potential than the gas diffusion electrode without gradient microporous layer in 1M KOH electrolyte, indicating that the gas diffusion electrode with gradient microporous layer can improve the electrolysis performance.
[0049] The electrochemical impedance spectroscopy curves in 1M potassium hydroxide (KOH) electrolyte are shown in Figure 7. It can be seen that the gas diffusion electrode with gradient microporous layer has smaller curve slope at low frequency than the gas diffusion electrode without gradient microporous layer, indicating that it has lower mass transfer impedance. Figure 5
[0050] The constant current test curves in 1M potassium hydroxide (KOH) electrolyte are shown in Figure 8. It can be seen that after 300 seconds of constant current electrolysis and 300 seconds of stop electrolysis, the gas diffusion electrode with gradient microporous layer has lower potential at low frequency than the gas diffusion electrode without gradient microporous layer, and has significantly lower potential rise amplitude during constant current electrolysis. This is because the gas bubbles generated during constant current electrolysis are removed faster in the gas diffusion electrode with gradient microporous layer, indicating that it has better bubble removal ability. Figure 6
[0051] In summary, the synthesized gas diffusion electrode with gradient microporous layer has better bubble removal ability and electrolysis performance than the gas diffusion electrode without gradient microporous layer.
[0052] It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.
[0053] The above describes the present application and its embodiments, which are not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. In general, if those skilled in the art are inspired by it, without departing from the purpose of the present application, without creative design, similar structure and embodiments of the technical solution can be designed, which should all belong to the protection scope of the present application.
Claims
1. A gas diffusion electrode with gradient microporous layer, characterized in that: comprising a substrate, a gradient microporous layer disposed on one side of the substrate, and a catalyst layer disposed on the side of the gradient microporous layer away from the substrate; the gradient microporous layer is stacked by at least two microporous sub-layers with different porosities, and the porosity of the microporous sub-layers gradually increases along the direction from the substrate to the catalyst layer; each microporous sub-layer is composed of an electrically conductive carbon material and a binder, the electrically conductive carbon material is selected from at least one of carbon black, graphene, and carbon nanotube, and the binder is selected from at least one of polytetrafluoroethylene and polyvinylidene fluoride. The difference in porosity between two adjacent microporous sub-layers in the gradient microporous layer is 5%-30%. The thickness of each microporous sub-layer is 10μm-200μm, and the total thickness of the gradient microporous layer is 50μm-500μm.
2. The gas diffusion electrode with gradient microporous layer according to claim 1, characterized in that: The substrate is an electrically conductive porous material selected from at least one of carbon paper, carbon cloth, and metal foam; the catalyst layer comprises a catalyst and an electrically conductive carrier, the catalyst is selected from at least one of platinum, ruthenium, iridium, and alloys thereof, and the electrically conductive carrier is selected from at least one of carbon black, carbon nanotube, and graphene.
3. The gas diffusion electrode with gradient microporous layer according to claim 1, characterized in that: The method comprises the following steps:
4. The gas diffusion electrode with gradient microporous layer according to claim 1, characterized in that: Preparation of microporous sub-layer slurries with different porosities: mix the electrically conductive carbon material and the binder in different proportions in a solvent to prepare at least two microporous sub-layer slurries with different porosities by adjusting the proportions of the electrically conductive carbon material and the binder; wherein the proportion of the electrically conductive carbon material in the microporous sub-layer slurry used subsequently gradually increases along the direction from the substrate to the catalyst layer; 5. A method for producing a gas diffusion electrode having a gradient microporous layer according to any one of claims 1 to 4, characterized by, Sequential coating of microporous sub-layer slurries on the substrate: place the substrate on a coating device, and sequentially coat the microporous sub-layer slurries with different porosities on one side of the substrate in the order of increasing porosity, and dry to form a gradient microporous layer; Preparation of a catalyst layer and compounding: mix the catalyst and the electrically conductive carrier in a solvent to prepare a catalyst layer slurry, coat the catalyst layer slurry on the side of the gradient microporous layer away from the substrate, and dry to obtain a gas diffusion electrode with a gradient microporous layer. The solvent is selected from at least one of ethanol, isopropanol, and N-methyl pyrrolidone; the drying temperature is 60℃-120℃, and the drying time is 1h-6h. In the preparation of microporous sub-layer slurries with different porosities, ultrasonic treatment or ball milling treatment is also used to disperse the components uniformly, the power of the ultrasonic treatment is 100W-500W, and the time is 0.5h-2h; the rotation speed of the ball milling treatment is 200r / min-800r / min, and the time is 1h-5h.
6. The method of claim 5, wherein the gas diffusion electrode having a gradient microporous layer is prepared by the steps of: The method for coating the microporous sub-layer slurry and the catalyst layer slurry is selected from at least one of spraying, doctor blading, and screen printing.
7. The method of claim 5, wherein the gas diffusion electrode having a gradient microporous layer is prepared by the steps of: 9.Use of the gas diffusion electrode with a gradient microporous layer according to any one of claims 1-4 in a fuel cell.
8. The method of claim 5, wherein the gas diffusion electrode having a gradient microporous layer is prepared by the steps of: The fuel cell is selected from at least one of a proton exchange membrane fuel cell, an alkaline fuel cell, a molten carbonate fuel cell, and a solid oxide fuel cell. 10. Use of a gas diffusion electrode with a gradient microporous layer according to claim 9, characterized in that: