CN115312821A - Membrane electrode, membrane electrode assembly and preparation method thereof - Google Patents

Membrane electrode, membrane electrode assembly and preparation method thereof Download PDF

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CN115312821A
CN115312821A CN202211080550.XA CN202211080550A CN115312821A CN 115312821 A CN115312821 A CN 115312821A CN 202211080550 A CN202211080550 A CN 202211080550A CN 115312821 A CN115312821 A CN 115312821A
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anode
membrane electrode
electrode assembly
catalyst layer
cathode
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蔡超
艾勇诚
陈�峰
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Sany Electric Vehicle Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8803—Supports for the deposition of the catalytic active composition
    • H01M4/881—Electrolytic membranes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8825—Methods for deposition of the catalytic active composition
    • H01M4/8828—Coating with slurry or ink
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9041—Metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9075—Catalytic material supported on carriers, e.g. powder carriers
    • H01M4/9083—Catalytic material supported on carriers, e.g. powder carriers on carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H01M4/921—Alloys or mixtures with metallic elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
    • H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Abstract

The invention relates to the technical field of fuel cells, in particular to a membrane electrode, a membrane electrode assembly and a preparation method thereof. The membrane electrode assembly includes: the proton exchange membrane comprises a proton exchange membrane, two anode catalyst layers arranged in contact with each other and a cathode catalyst layer; two anode catalyst layers and one cathode catalyst layer which are arranged in contact with each other are respectively arranged on two sides of the proton exchange membrane; the first anode catalyst layer is arranged in contact with the proton exchange membrane, and an anode catalyst in the first anode catalyst layer is a non-Pt catalyst capable of catalyzing hydrogen oxidation reaction; the anode catalyst in the second anode catalytic layer is Pt/C. The membrane electrode assembly can effectively cut off an electric loop generated by a 'reverse current mechanism' of an anode hydrogen-air interface in the start-stop process, thereby effectively inhibiting the oxidation of a cathode carbon material, further enabling the membrane electrode to have a 'start-stop' protection function, and obviously reducing the damage of the start-stop process to the membrane electrode of a fuel cell.

Description

Membrane electrode, membrane electrode assembly and preparation method thereof
Technical Field
The invention relates to the technical field of fuel cells, in particular to a membrane electrode, a membrane electrode assembly and a preparation method thereof.
Background
The hydrogen fuel cell is a device capable of directly converting chemical energy in hydrogen into electric energy, and has the characteristics of high energy conversion efficiency, no pollution and the like. The membrane electrode is the "heart" of the hydrogen fuel cell and the electrochemical reaction takes place in the membrane electrode. The membrane electrode is generally composed of an anode catalyst layer, a cathode catalyst layer, a proton exchange membrane, an anode gas diffusion layer, and a cathode gas diffusion layer. The anode catalyst layer is subjected to a Hydrogen Oxidation Reaction (HOR) and is generally composed of a Pt/C catalyst and a proton conductive resin. The cathode catalyst layer undergoes an Oxygen Reduction Reaction (ORR), and is also generally composed of a Pt/C catalyst and a proton conductive resin. Proton exchange membranes are typically composed of perfluorosulfonic resins, which function primarily to conduct protons, and to sequester electrons and gases. The cathode and anode gas diffusion layers are generally composed of carbon paper or carbon cloth and a microporous layer on one side, and are used for transporting air and hydrogen to the cathode and anode catalyst layers and discharging excess water, respectively.
During the start-stop process of the fuel cell, a certain amount of air (mainly coming from permeation of cathode air through the proton exchange membrane and permeation of the pipe) is easily mixed in the anode catalyst layer, so that a hydrogen-air interface is formed, as shown in fig. 2. The air area of the anode catalytic layer can generate oxygen reduction reaction under the catalytic action of the Pt/C catalyst, so that the potential of the local position of the cathode catalytic layer is raised. The above-mentioned partial (IV) potential of the cathode catalytic layer can even reach 2.0V, forcing the water in this region to undergo Oxygen Evolution Reaction (OER) and the carbon support to undergo Carbon Oxidation Reaction (COR). The carbon carrier serves as a catalyst, a carrier and a framework of the catalyst layer, and oxidation of the carbon carrier can cause a large amount of Pt to be lost, even cause the framework of the catalyst layer to collapse, and seriously damage the performance of the battery.
In the prior art, cn201180061661.X discloses an improved membrane electrode assembly for PEM fuel cells, having two electrode layers (EL 1 and/or EL 2), at least one of which comprises a first electrocatalyst (EC 1) comprising an iridium oxide component in combination with at least one other inorganic oxide component; and a second electrocatalyst (EC 2/EC 2') which is free of iridium. Preferably, an iridium oxide/titanium dioxide catalyst is used as EC1. These membrane electrodes exhibit excellent performance, especially under severe operating conditions such as fuel starvation and start/stop cycling. However, the iridium oxide accelerates the water electrolysis reaction to inhibit the corrosion of the cathode carbon material and prevent the performance degradation of the battery, so that the degradation mechanism in the starting and stopping process cannot be fundamentally eliminated, and the protection effect is limited.
Disclosure of Invention
In view of this, the present invention provides a membrane electrode assembly,
the method comprises the following steps: the proton exchange membrane comprises a proton exchange membrane, two layers of anode catalyst layers and a layer of cathode catalyst layer which are arranged in contact;
the two anode catalyst layers and the one cathode catalyst layer which are arranged in contact with each other are respectively arranged on two sides of the proton exchange membrane;
the first anode catalyst layer is arranged in contact with the proton exchange membrane, and an anode catalyst in the first anode catalyst layer is a non-Pt catalyst capable of catalyzing hydrogen oxidation reaction;
the anode catalyst in the second anode catalytic layer is Pt/C.
According to the membrane electrode assembly provided by the invention, the ratio of the thickness of the second anode catalyst layer to the thickness of the first anode catalyst layer is less than 1.
According to the membrane electrode assembly provided by the invention, in the first or second anode catalyst layer, the weight percentage of the anode catalyst in the anode catalyst layer is 30-70%.
According to the membrane electrode assembly provided by the invention, the anode catalyst in the first anode catalyst layer is at least one of Ru/C, ir/C and IrRu/C.
According to the membrane electrode assembly provided by the invention, the cathode catalyst layer contains a cathode catalyst Pt/C.
According to the membrane electrode assembly provided by the present invention, the first or second anode catalytic layer further comprises: a perfluorosulfonic acid resin;
preferably, the weight percentage of the perfluorinated sulfonic acid resin in the anode catalyst layer is 30-70%.
The invention also provides a preparation method of the membrane electrode assembly, which comprises the following steps:
(1) Dispersing the material of the anode catalyst layer in a solvent to prepare anode slurry; dispersing the material of the cathode catalyst layer in a solvent to prepare cathode slurry;
(2) And sequentially coating the first anode slurry and the second anode slurry on one side of the proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
According to the preparation method of the membrane electrode assembly provided by the invention, the solvent comprises an alcohol solution.
According to the preparation method of the membrane electrode assembly provided by the invention, the solvent is an aqueous solution of alcohol, the alcohol is preferably at least one of n-propanol, isopropanol, ethanol and ethylene glycol, and the weight ratio of water to alcohol is 1:4 to 4.
According to the preparation method of the membrane electrode assembly, the coating mode comprises direct coating and indirect coating;
the direct coating comprises a spraying or slit extrusion mode;
the indirect coating is specifically as follows: respectively coating the second anode slurry and the cathode slurry on a PTFE substrate to form a second anode catalyst layer and a cathode catalyst layer, and then coating the first anode slurry on the second anode catalyst layer to form a first anode catalyst layer; and then transferring the first anode catalytic layer, the second anode catalytic layer and the cathode catalytic layer to the proton exchange membrane.
The invention also provides a membrane electrode assembly prepared by any one of the preparation methods.
The present invention also provides a membrane electrode comprising the membrane electrode assembly according to any of the above embodiments.
Compared with the prior art, the invention has the beneficial effects that:
the anode of the membrane electrode is provided with two anode catalyst layers, wherein the anode catalyst layer in contact with a proton exchange membrane contains a non-Pt catalyst capable of catalyzing hydrogen oxidation reaction, and the surface of the anode catalyst layer is provided with a Pt/C anode catalyst layer, so that an electric loop generated by a reverse current mechanism of an anode hydrogen-air interface in a start-stop process can be effectively cut off, the oxidation of a cathode carbon material is effectively inhibited, the membrane electrode has a 'start-stop' resistant protection function, and the damage of the start-stop process to the membrane electrode of a fuel cell is remarkably reduced; the second anode catalyst layer contains a small amount of Pt/C catalyst which can efficiently catalyze the hydrogen oxidation reaction, and the performance reduction caused by the first anode catalyst layer can be compensated. Moreover, the invention adopts a material solution scheme, and can effectively relieve the design pressure of the control strategy of the fuel cell system.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic structural view of a start-stop membrane electrode assembly of the present invention; wherein 1 denotes a proton exchange membrane, 2 denotes a cathode catalyst layer, 3 denotes a first anode catalyst layer, and 4 denotes a second anode catalyst layer.
Fig. 2 is a schematic diagram of a "reverse current mechanism" of a membrane electrode of the prior art.
FIG. 3 is a schematic diagram of the design principle of the membrane electrode assembly with the "start-stop" protection function according to the invention.
FIG. 4 is a polarization curve before and after an accelerated start-stop experiment of a comparative example membrane electrode.
Fig. 5 is a cyclic voltammogram before and after the aging experiment of the comparative cathode catalyst layer.
FIG. 6 is a polarization curve before and after the start-stop acceleration experiment of the membrane electrode of the present invention.
Fig. 7 is a cyclic voltammogram before and after the aging experiment of the cathode catalyst layer according to the present invention.
FIG. 8 is a schematic structural view of a start-stop membrane electrode of the present invention; in the following, 1 denotes a proton exchange membrane, 2 denotes a cathode catalyst layer, 3 denotes a first anode catalyst layer, 4 denotes a second anode catalyst layer, 5 denotes an anode gas diffusion layer, and 6 denotes a cathode gas diffusion layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As an embodiment of the present invention, the present embodiment provides a membrane electrode assembly including: the proton exchange membrane comprises a proton exchange membrane, two anode catalyst layers arranged in contact with each other and a cathode catalyst layer;
the two anode catalyst layers and the one cathode catalyst layer which are arranged in contact with each other are respectively arranged on two sides of the proton exchange membrane;
the first anode catalyst layer is arranged in contact with the proton exchange membrane, and an anode catalyst in the first anode catalyst layer is a non-Pt catalyst capable of catalyzing a hydrogen oxidation reaction;
the anode catalyst in the second anode catalytic layer is Pt/C.
The structural schematic diagram of the start-stop membrane electrode assembly of the present embodiment is shown in fig. 1; wherein 1 denotes a proton exchange membrane, 2 denotes a cathode catalyst layer, 3 denotes a first anode catalyst layer, and 4 denotes a second anode catalyst layer.
Through mechanism research, the invention discovers that a reverse current mechanism as shown in fig. 2 occurs on a membrane electrode adopted in the prior art, and specifically, a cathode catalyst layer forms a high local high potential (> 2.0V) to accelerate oxidation reaction of a carbon carrier, so that the cathode catalyst layer Pt is lost and collapsed.
In the prior art, although there is a technical scheme aiming at improving the membrane electrode start-stop durability, the principle of the solution adopted in the technical scheme plays a role completely different from the application. For example: CN201180061661.X is designed with a double-layer cathode catalyst layer, wherein one layer is made of iridium oxide, and the technical principle is that iridium oxide accelerates water electrolysis reaction to inhibit corrosion of cathode carbon material and prevent battery performance from declining.
Aiming at the mechanism discovered by the inventor, the anode of the membrane electrode is provided with two anode catalyst layers, wherein the anode catalyst layer in contact with the proton exchange membrane contains a non-Pt catalyst capable of catalyzing the hydrogen oxidation reaction, so that an electric loop generated by a reverse current mechanism of an anode hydrogen-air interface in the starting and stopping process can be effectively cut off, the oxidation of a cathode carbon material is inhibited, the performance degradation of the battery is prevented, the second anode catalyst layer contains a small amount of Pt/C catalyst capable of efficiently catalyzing the hydrogen oxidation reaction, and the performance degradation caused by the first anode catalyst layer can be compensated. The schematic diagram of the design principle of the membrane electrode assembly with the 'start-stop' protection function is shown in figure 3.
As a preferred embodiment of the present invention, in the first or second anode catalytic layer, the weight percentage of the anode catalyst in the anode catalytic layer is 30% to 70%.
As a preferred embodiment of the invention, the anode catalyst in the first anode catalyst layer is at least one of Ru/C, ir/C and IrRu/C.
By selecting the anode catalyst, the protection effect of 'start-stop resistance' is better, the oxidation of a cathode carbon material can be inhibited to a greater extent, and the performance of the battery is further improved.
As a preferred embodiment of the invention, the cathode catalyst layer contains a cathode catalyst Pt/C.
As a preferred embodiment of the present invention, the first or second anode catalytic layer further comprises: a perfluorosulfonic acid resin;
preferably, the perfluorinated sulfonic acid resin accounts for 30-70 wt% of the anode catalyst layer.
As an embodiment of the present invention, the present embodiment provides a method of manufacturing a membrane electrode assembly, including:
(1) Dispersing the material of the anode catalyst layer in a solvent to prepare anode slurry; dispersing the material of the cathode catalyst layer in a solvent to prepare cathode slurry;
(2) And sequentially coating the first anode slurry and the second anode slurry on one side of a proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
The preparation method disclosed by the invention is simple in process and easy for batch production.
As a preferred embodiment of the present invention, the solvent comprises an aqueous alcohol solution.
In a preferred embodiment of the present invention, the solvent is an aqueous solution of an alcohol, the alcohol is preferably at least one of n-propanol, isopropanol, ethanol and ethylene glycol, and the weight ratio of water to alcohol is 1: 4-4.
As a preferred embodiment of the invention, the coating mode comprises direct coating and indirect coating;
the direct coating comprises a spraying or slit extrusion mode;
the indirect coating is specifically as follows: respectively coating the second anode slurry and the cathode slurry on a PTFE (polytetrafluoroethylene) substrate to form a second anode catalyst layer and a cathode catalyst layer, and then coating the first anode slurry on the second anode catalyst layer to form a first anode catalyst layer; and then transferring the first anode catalytic layer, the second anode catalytic layer and the cathode catalytic layer to the proton exchange membrane.
As a more preferred embodiment of the present invention, the preparation method comprises the following steps:
(1) Mixing a non-Pt catalyst capable of catalyzing a hydrogen oxidation reaction, perfluorinated sulfonic acid resin and a solvent, performing ultrasonic dispersion, and stirring at a rotating speed of more than 8000rpm to prepare first anode slurry;
mixing a Pt/C catalyst, perfluorinated sulfonic acid resin and a solvent, ultrasonically dispersing, and stirring at a rotating speed of more than 8000rpm to prepare second anode slurry;
the solvent is water and alcohol according to a weight ratio of 1: 4-4;
mixing a Pt/C catalyst, perfluorinated sulfonic acid resin and the solvent, ultrasonically dispersing, and stirring at a rotating speed of more than 8000rpm to prepare cathode slurry;
(2) And sequentially coating the first anode slurry and the second anode slurry on one side of a proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
This example provides, as an example of the present invention, a membrane electrode assembly prepared by any of the examples described above.
This example provides, as an example of the present invention, a membrane electrode comprising the membrane electrode assembly of any of the above examples.
As a preferred embodiment of the present invention, the membrane electrode assembly was prepared by placing the prepared membrane electrode assembly between 2 gas diffusion layers.
As a preferred embodiment of the present invention, the gas diffusion layer is carbon fiber paper or carbon fiber cloth coated with carbon powder on the surface.
Because the membrane electrode assembly with the start-stop resisting function is contained in the membrane electrode, the membrane electrode in the embodiment also has the start-stop resisting function, so that the damage to the membrane electrode of the fuel cell in the start-stop process can be obviously reduced, and the service life of the membrane electrode is prolonged.
The schematic structural diagram of the membrane electrode of the above embodiment of the present invention is shown in fig. 8; in the following, 1 denotes a proton exchange membrane, 2 denotes a cathode catalyst layer, 3 denotes a first anode catalyst layer, 4 denotes a second anode catalyst layer, 5 denotes an anode gas diffusion layer, and 6 denotes a cathode gas diffusion layer.
The technical solutions and advantageous effects of the present invention will be explained below with reference to more specific examples.
The following examples, where specific techniques or conditions are not indicated, are all performed in the conventional manner or according to techniques or conditions described in literature in the art or according to the product specifications. The reagents and instruments used are conventional products which are available from normal commercial vendors, not indicated by manufacturers.
Example 1
The present embodiment provides a membrane electrode assembly, which is prepared as follows:
(1) 1g of catalyst Ru/C (50 wt.%) and 20g of perfluorosulfonic acid resin solution (5 wt.%) were dispersed in 20mL of solvent, water, n-propanol in a weight ratio of 1:1, ultrasonically dispersing the mixed solution for 5min, and stirring at a rotating speed of 8000rpm to prepare first anode slurry;
dispersing 0.1g of catalyst Pt/C (50 wt.%), 2g of perfluorosulfonic acid resin solution (5 wt.%) in 10mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain a second anode slurry;
(2) Dispersing 1g of catalyst Pt/C (50 wt.%), 20g of perfluorosulfonic acid resin solution (5 wt.%) in 20mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain cathode slurry;
(3) And sequentially coating the first anode slurry and the second anode slurry on one side of the proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
Further, the membrane electrode assembly is placed between 2 gas diffusion layers to prepare the start-stop membrane electrode, and the gas diffusion layers are carbon fiber paper coated with carbon powder on the surfaces.
Example 2
The present embodiment provides a membrane electrode assembly, which is prepared as follows:
(1) 1g of catalyst Ir/C (50 wt.%) and 20g of perfluorosulfonic acid resin solution (5 wt.%) were dispersed in 20mL of a solvent, water, n-propanol in a weight ratio of 1:1, ultrasonically dispersing the mixed solution for 5min, and stirring at a rotating speed of 8000rpm to prepare first anode slurry;
dispersing 0.1g of catalyst Pt/C (50 wt.%), 2g of perfluorosulfonic acid resin solution (5 wt.%) in 10mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain a second anode slurry;
(2) Dispersing 1g of catalyst Pt/C (50 wt.%), 20g of perfluorosulfonic acid resin solution (5 wt.%) in 20mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain cathode slurry;
(3) And sequentially coating the first anode slurry and the second anode slurry on one side of the proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
Further, the membrane electrode assembly is placed between 2 gas diffusion layers to prepare the start-stop membrane electrode, and the gas diffusion layers are carbon fiber paper coated with carbon powder on the surfaces.
Example 3
The present embodiment provides a membrane electrode assembly, which is prepared as follows:
(1) 1g of catalyst RuIr/C (50 wt.%) and 20g of perfluorosulfonic resin solution (5 wt.%) were dispersed in 20mL of solvent, water, n-propanol in a weight ratio of 1:1, ultrasonically dispersing the mixed solution for 5min, and stirring at a rotating speed of 8000rpm to prepare first anode slurry;
dispersing 0.1g of catalyst Pt/C (50 wt.%), 2g of perfluorosulfonic acid resin solution (5 wt.%) in 10mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain second anode slurry;
(2) Dispersing 1g of catalyst Pt/C (50 wt.%), 20g of perfluorosulfonic acid resin solution (5 wt.%) in 20mL of the above solvent, ultrasonically dispersing for 5min, and stirring at 8000rpm to obtain cathode slurry;
(3) And sequentially coating the first anode slurry and the second anode slurry on one side of the proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
Further, the membrane electrode assembly is placed between 2 gas diffusion layers to prepare the start-stop membrane electrode, and the gas diffusion layers are carbon fiber paper coated with carbon powder on the surfaces.
Comparative example
This comparative example provides a membrane electrode assembly, which was prepared by a method different from that of example 1 only: the anode catalytic layer is a layer of Pt/C catalyst.
Further, the membrane electrode assembly is placed between 2 gas diffusion layers to prepare a conventional membrane electrode, wherein the gas diffusion layers are carbon fiber paper coated with carbon powder on the surface.
Test examples
The active area is 25cm 2 The membrane electrode prepared in examples and comparative examples was fully activated after the cell was assembled. The activation conditions are as follows: the hydrogen excess coefficient of the anode is 1.5, the air excess coefficient of the cathode is 2.0 at the temperature of 80 ℃,the current density is lower than 400mA/cm 2 At a rate of 400mA/cm 2 Current density flow feed, 100%/100% relative humidity, 100kPa/100kPa backpressure. After activation, the single cell polarization curve and the cathode CV curve are tested, and the polarization curve is identical to the activation condition. CV curve test conditions: at 30 ℃,100 percent of relative humidity hydrogen at the anode and 100 percent of relative humidity nitrogen at the cathode, the flow rate of the cathode and the anode is 200mL/200mL, the sweep rate is 20mV/s, and the sweep range is 0.1V-1.20V.
After the experiment is completed, starting and stopping an accelerated experiment, wherein the accelerated experiment refers to a DOE test method, and the experiment conditions are as follows: 35 ℃ and normal pressure. The whole accelerated experiment is 5000 cycles, the steps in each cycle are shown in table 1, and the air flow in the whole experiment process is a fixed value (the excess factor is 2.0, 1.0A/cm) 2 The corresponding flow value at current density). And after the start-stop acceleration experiment is finished, testing the polarization curve and the cathode CV curve of the monocell.
TABLE 1 Start-stop test method
Figure BDA0003832956230000101
Figure BDA0003832956230000111
The polarization curves before and after the membrane electrode start-stop acceleration test of the comparative example are shown in fig. 4. After the accelerated aging test, the performance of the battery was significantly deteriorated. The decrease in cell performance at low current densities indicates a greater degree of degradation of the cathode catalyst. To verify the guess, cyclic Voltammograms (CVs) before and after the cathode catalytic layer aging experiment were tested, as shown in fig. 5. As is apparent from fig. 5, after the aging test, the CV of the cathode catalyst layer was largely changed, for example, the double capacitor layer was significantly broadened, which means that the carbon support was significantly corroded.
The polarization curves before and after the start-stop acceleration experiment of the start-stop membrane electrode of the embodiment 1 of the invention are shown in fig. 6. After accelerated aging experiments, the battery performance changes less, especially at low current densities. Overall, the performance degradation is significantly lower than that of the conventional membrane electrode, which indicates that the start-stop resistant membrane electrode designed by the invention can significantly reduce the aging effect in the start-stop process. In addition, CV curves of the cathode catalyst layer before and after aging experiments of the start-stop membrane electrode are also measured, as shown in fig. 7, the cathode catalyst layer is basically unchanged before and after aging, which shows that the membrane electrode can effectively prevent the cathode from generating high potential, so that the degradation of the cathode catalyst layer is inhibited.
The results of comparing the start-stop resistance of the membrane electrodes of the above examples and comparative examples are shown in table 2.
TABLE 2 comparison of the Start-stop resistance of the membrane electrodes of the examples and comparative examples
Figure BDA0003832956230000112
Figure BDA0003832956230000121
As can be seen from comparison of data in Table 2, the start-stop-resistant membrane electrode disclosed by the invention can obviously reduce the aging and damage effects of the start-stop process on the membrane electrode, and effectively prolong the service life of the cell.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A membrane electrode assembly, comprising: the proton exchange membrane comprises a proton exchange membrane, two layers of anode catalyst layers and a layer of cathode catalyst layer which are arranged in contact;
the two anode catalyst layers and the one cathode catalyst layer which are arranged in contact with each other are respectively arranged on two sides of the proton exchange membrane;
the first anode catalyst layer is arranged in contact with the proton exchange membrane, and an anode catalyst in the first anode catalyst layer is a non-Pt catalyst capable of catalyzing hydrogen oxidation reaction;
the anode catalyst in the second anode catalytic layer is Pt/C.
2. The membrane electrode assembly according to claim 1, wherein the anode catalyst accounts for 30 to 70% by weight of the anode catalyst layer in the first or second anode catalyst layer.
3. A membrane electrode assembly according to claim 1 or 2, wherein the anode catalyst in the first anode catalytic layer is at least one of Ru/C, ir/C, irRu/C.
4. A membrane electrode assembly according to any one of claims 1 to 3, wherein the cathode catalytic layer contains a cathode catalyst Pt/C.
5. A membrane electrode assembly according to any one of claims 1 to 4, wherein the first or second anode catalytic layer further comprises: a perfluorosulfonic acid resin;
preferably, the weight percentage of the perfluorinated sulfonic acid resin in the anode catalyst layer is 30-70%.
6. The method of producing a membrane electrode assembly according to any one of claims 1 to 5, comprising:
(1) Dispersing the material of the anode catalyst layer in a solvent to prepare anode slurry; dispersing the material of the cathode catalyst layer in a solvent to prepare cathode slurry;
(2) And sequentially coating the first anode slurry and the second anode slurry on one side of a proton exchange membrane, and coating the cathode slurry on the other side of the proton exchange membrane to obtain the membrane electrode assembly.
7. The method for preparing a membrane electrode assembly according to claim 6, wherein the solvent is an aqueous solution of an alcohol, preferably at least one of n-propanol, isopropanol, ethanol and ethylene glycol, and the weight ratio of water to alcohol is 1:4 to 4.
8. The method of producing a membrane electrode assembly according to claim 6 or 7, wherein the coating manner includes direct coating and indirect coating;
the direct coating is spraying or slit extrusion;
the indirect coating is specifically as follows: respectively coating the second anode slurry and the cathode slurry on a PTFE substrate to form a second anode catalyst layer and a cathode catalyst layer, and then coating the first anode slurry on the second anode catalyst layer to form a first anode catalyst layer; and then transferring the first anode catalytic layer, the second anode catalytic layer and the cathode catalytic layer to the proton exchange membrane.
9. A membrane electrode assembly produced by the method for producing a membrane electrode assembly according to any one of claims 6 to 8.
10. A membrane electrode comprising the membrane electrode assembly according to any one of claims 1 to 5 or the membrane electrode assembly according to claim 9.
CN202211080550.XA 2022-09-05 2022-09-05 Membrane electrode, membrane electrode assembly and preparation method thereof Pending CN115312821A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116926618A (en) * 2023-09-15 2023-10-24 北京英博新能源有限公司 Catalyst coating proton membrane with composite catalytic layer structure, preparation method thereof and water electrolysis equipment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116926618A (en) * 2023-09-15 2023-10-24 北京英博新能源有限公司 Catalyst coating proton membrane with composite catalytic layer structure, preparation method thereof and water electrolysis equipment
CN116926618B (en) * 2023-09-15 2023-12-01 北京英博新能源有限公司 Catalyst coating proton membrane with composite catalytic layer structure, preparation method thereof and water electrolysis equipment

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