A proton exchange membrane water electrolysis membrane electrode with a mixed ionomer constructed catalytic layer and a preparation method thereof

Abstract

The application discloses a membrane electrode prepared by mixing long-side-chain ionomers and short-side-chain ionomers in proportion and a preparation method thereof, and belongs to the technical field of water electrolysis membrane electrode preparation. The method mixes long-side-chain ionomers, short-side-chain ionomers, a catalyst and a solvent, and performs ultrasonic treatment under appropriate conditions until the ionomers are uniformly dispersed. Subsequently, the ionomers are coated on a proton exchange membrane, and heat pressing treatment is performed to make the ionomers more closely combined with the surface of the membrane, so that a membrane electrode is formed. In the process, the long-side-chain ionomers and the short-side-chain ionomers improve the structural stability of a catalyst layer and the dispersity of the catalyst through synergistic effect, and optimize the performance of the membrane electrode.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of proton exchange membrane water electrolysis hydrogen energy conversion, and particularly relates to a proton exchange membrane water electrolysis membrane electrode with a mixed ionomer constructed catalytic layer and a preparation method thereof. BACKGROUND

[0002] Proton exchange membrane water electrolysis (PEMWE) technology, with its high current density, high conversion efficiency, fast response and start-up performance, and good adaptability to renewable energy fluctuations, has become an ideal technical means for the preparation of "green hydrogen". Especially under the promotion of the "double carbon" goal, PEMWE technology has broad application prospects and is one of the key technologies for realizing sustainable hydrogen energy production.

[0003] In the working process of the electrolysis cell, water is injected into the membrane electrode anode through the water inlet system, and oxygen is generated at the anode and hydrogen is generated at the cathode through electrode reaction. In this process, the reaction kinetics of the anode oxygen evolution reaction (OER) and the cathode hydrogen evolution reaction (HER) determines the overall efficiency of the electrolysis cell. Since the anode OER involves a multi-electron transfer process, the kinetics is relatively slow, and its performance has a high dependence on the structure design of the membrane electrode and the activity and stability of the catalytic layer. At the same time, although the HER reaction at the cathode has fast kinetics, the dispersion, stability and conductivity of the catalyst still have important influence on the reaction efficiency. Therefore, the reasonable design of the catalytic layer is crucial to improve the overall performance of the electrolysis cell.

[0004] Chinese patent application CN119020800A introduces a second anode and a second cathode in the membrane electrode assembly, the content of perfluorosulfonic acid ionomer in the second cathode catalyst layer is lower than that in the first cathode catalyst layer; the content of perfluorosulfonic acid ionomer in the second anode catalyst layer is lower than that in the first anode catalyst layer. While enhancing the binding force of the catalytic layer and the proton exchange membrane, the contact resistance of the catalytic layer and the GDL is reduced. Chinese patent application CN119133473A improves the migration rate of the ionomer main chain and side chain in the catalytic layer by heat treatment of the membrane electrode, so that the ionomer cluster structure in the catalytic layer changes, the ohmic loss is reduced, and the overall electrolysis performance of the membrane electrode is improved, thereby reducing the operating cost of the hydrogen production by water electrolysis and the fuel cell operation process. SUMMARY

[0005] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0006] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0007] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and provide a preparation method of a proton exchange membrane water electrolysis membrane electrode constructed by a mixed ionomer.

[0008] To solve the above technical problems, the present application provides the following technical scheme: a preparation method of a proton exchange membrane water electrolysis membrane electrode constructed by a mixed ionomer, characterized in that it comprises,

[0009] The oxygen evolution catalyst is mixed with long-chain ionomer, short-chain ionomer and solvent, and ultrasonic dispersion is performed until uniform dispersion is achieved, to obtain a mixed layer anode catalyst slurry;

[0010] The hydrogen evolution catalyst is mixed with long-chain ionomer and solvent, and ultrasonic dispersion is performed until uniform dispersion is achieved, to obtain a cathode catalyst slurry;

[0011] The cathode catalyst slurry and the anode catalyst slurry are respectively coated onto a polytetrafluoroethylene film to obtain a catalytic layer;

[0012] The above cathode catalyst layer, proton exchange membrane and anode catalyst layer are stacked in order, and are transferred to both sides of the proton exchange membrane by hot pressing, to obtain a membrane electrode.

[0013] As a preferred scheme of the preparation method of the present application, the oxygen evolution catalyst is an anode oxygen evolution catalyst suitable for water electrolysis, including but not limited to iridium-based catalyst.

[0014] As a preferred scheme of the preparation method of the present application, the hydrogen evolution catalyst is a cathode hydrogen evolution catalyst suitable for water electrolysis, including but not limited to platinum-based catalyst.

[0015] As a preferred scheme of the preparation method of the present application, the solvent is one or more of water, ethanol and isopropanol.

[0016] As a preferred scheme of the preparation method of the present application, the mass fraction of the ionomer in the catalytic layer solid is 5% to 80%.

[0017] As a preferred scheme of the preparation method of the present application, the mass ratio of the anode oxygen evolution catalyst, the cathode hydrogen evolution catalyst and the pore-forming agent is 100:1 to 1:100, and the mass ratio of the anode oxygen evolution catalyst and the solvent is 1:5 to 1:100.

[0018] As a preferred scheme of the preparation method of the present application, the temperature of the hot pressing is 120 to 135℃, and the pressure is 10 to 30MPa.

[0019] Still another object of the present application is to provide a proton exchange membrane water electrolysis membrane electrode with a catalytic layer constructed by mixed ionomer to overcome the deficiencies in the prior art.

[0020] Still another object of the present application is to provide an application of the proton exchange membrane water electrolysis membrane electrode with a catalytic layer constructed by mixed ionomer in water electrolysis technology to overcome the deficiencies in the prior art.

[0021] The present application has the following advantages:

[0022] (1) The present application provides a proton exchange membrane water electrolysis membrane electrode and a preparation method thereof. The method blends long-side-chain ionomer and short-side-chain ionomer to improve catalyst utilization and ionomer distribution. The membrane electrode prepared by the present application exposes more electrochemical active area in the catalytic layer, provides better proton conduction ability, and improves the performance expression and long-term stability of the membrane electrode.

[0023] (2) The present application can form a more uniform network structure in the catalytic layer by using long-side-chain ionomer and short-side-chain ionomer, which improves the electrochemical active area of the catalytic layer. In addition, the introduction of short-side-chain ionomer improves the proton conductivity of the membrane electrode, while long-side-chain ionomer enhances the mechanical strength and chemical stability of the catalytic layer. The combination of mixed ionomers effectively improves the utilization of catalysts and significantly improves the electrochemical performance and stability of the membrane electrode. The new membrane electrode of the present application significantly reduces the mass transfer resistance of the membrane electrode in the water electrolysis process, optimizes the transport of reactants, and thus improves the overall efficiency and stability of the PEMWE system. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0025] Figure 1 It is the scanning electron microscope graph of the catalytic layer of Example 1.

[0026] Figure 2 It is the scanning electron microscope graph of the catalytic layer of Comparative Example 1.

[0027] Figure 3 It is the water electrolysis polarization curve of the membrane electrode of Example 1, 2, 3 and Comparative Example 1, 2.

[0028] Figure 4 It is the long-term stability of the membrane electrode of water electrolysis of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0029] In order to make the above objectives, features and advantages of the present application more obvious and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the description examples.

[0030] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the present application, so the present application is not limited to the specific examples disclosed below.

[0031] Secondly, the "one embodiment" or "embodiment" referred to herein means that a specific feature, structure or characteristic can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent of or mutually exclusive with other embodiments.

[0032] Unless otherwise specified, the materials used in the embodiments of the present application are all ordinary commercially available.

[0033] Example 1

[0034] (1) A certain amount of iridium-based catalyst was weighed, and then isopropyl alcohol, water, Nafion solution and Aquivion solution were added (mass ratio, IrO2:Nafion:Aquivion = 8:0.5:1.5). The mixture was dispersed in an ice water bath at low temperature and ultrasonicated until uniform, to obtain an anode catalyst slurry.

[0035] (2) A certain amount of commercial Pt / C catalyst was weighed, and then water, isopropyl alcohol and 5% Nafion solution were added in sequence (Pt / C:Nafion = 1.5:1). The mixture was dispersed in an ultrasonic bath until uniform, to obtain a cathode catalyst slurry.

[0036] (3) A polytetrafluoroethylene film was placed on a hot plate and fixed using the negative pressure of an air compressor. The temperature of the hot plate was set to 80-90°C, and a spraying device was used to uniformly spray the anode and cathode catalyst slurries on the polytetrafluoroethylene film, with an effective area of the catalyst layer of 2x2 cm 2 .

[0037] (4) The polytetrafluoroethylene film coated with the anode and cathode catalyst layers was placed on both sides of a N115 proton exchange membrane of appropriate size, and a CCM-type membrane electrode was obtained after hot pressing and transfer printing.

[0038] (5) The scanning electron microscope (SEM) photograph is shown in Figure 1 The surface of the catalyst layer of Example 1 is smooth, dense and flat.

[0039] (6) The water electrolysis performance of the membrane electrode was tested in an electrolytic cell at 80°C. The experimental results are shown in Table 2. When the current density was 2 A / cm 2 , the electrolysis voltage of the electrolytic cell was 1.809 V. Figure 3 Figure 4 The stability test is shown in Table 3. The performance did not attenuate after continuous operation for 50 hours at a current density of 2 A / cm 2 .

[0040] Example 2

[0041] (1) A certain amount of iridium-based catalyst was weighed, followed by the addition of isopropyl alcohol, water, Nafion solution and Aquivion solution (mass ratio, iridium-based catalyst: Nafion: Aquivion = 8: 1: 1). The above mixture was dispersed in an ultrasonic bath at low temperature ice water to mix uniformly, to obtain an anode catalyst slurry.

[0042] (2) A certain amount of commercial Pt / C catalyst was weighed, followed by the addition of water, isopropyl alcohol and 5% Nafion solution (Pt / C: Nafion = 1.5: 1). The above mixture was dispersed in an ultrasonic bath to mix uniformly, to obtain a cathode catalyst slurry.

[0043] (3) The polytetrafluoroethylene membrane was placed on a hot plate and fixed using the negative pressure of an air compressor. The temperature of the hot plate was set to 80-90°C, and the anode and cathode catalyst slurries were uniformly sprayed on the polytetrafluoroethylene membrane using a spraying device, with an effective area of the catalyst layer being 2x2 cm 2 .

[0044] (4) The polytetrafluoroethylene membrane coated with the anode and cathode catalyst layers was placed on both sides of a N115 proton exchange membrane of appropriate size, and a CCM type membrane electrode was obtained after hot pressing transfer printing.

[0045] (5) The water electrolysis performance of the membrane electrode was tested in an electrolytic cell at 80°C. The experimental results are shown in Table 2. When the current density was 2 A / cm 2 , the electrolysis voltage of the electrolytic cell was 1.809 V. Figure 3

[0046] Example 3

[0047] (1) A certain amount of iridium-based catalyst was weighed, followed by the addition of isopropyl alcohol, water, Nafion solution and Aquivion solution (mass ratio, iridium-based catalyst: Nafion: Aquivion = 8: 1.5: 0.5). The above mixture was dispersed in an ultrasonic bath at low temperature ice water to mix uniformly, to obtain an anode catalyst slurry.

[0048] ​​(2) A certain amount of commercial Pt / C catalyst was weighed, and water, isopropyl alcohol and 5% Nafion solution were added in sequence (Pt / C:Nafion = 1.5:1). The mixture was dispersed in an ultrasonic bath until it was uniformly mixed to obtain a cathode catalyst slurry.

[0049] (3) The polytetrafluoroethylene film was placed on a hot plate and fixed by negative pressure of an air compressor. The temperature of the hot plate was set to 80-90°C. The anode and cathode catalyst slurries were uniformly sprayed on the polytetrafluoroethylene film using a spraying device, and the effective area of the catalyst layer was 2x2 cm 2 .

[0050] (4) The polytetrafluoroethylene film coated with the anode and cathode catalyst layers was placed on both sides of a N115 proton exchange membrane of appropriate size, and a CCM-type membrane electrode was obtained after hot pressing and transfer printing.

[0051] (5) The water electrolysis performance of the membrane electrode was tested in an electrolytic cell at 80°C. The experimental results are shown in Figure 3 , and when the current density was 2 A / cm 2 , the electrolysis voltage of the electrolytic cell was 1.853 V.

[0052] Comparative Example 1

[0053] (1) A certain amount of iridium-based catalyst was weighed, and isopropyl alcohol, water and Aquivion solution were added in sequence (mass ratio, iridium-based catalyst:Aquivion = 4:1). The mixture was dispersed in an ultrasonic bath in a low-temperature ice water bath until it was uniformly mixed to obtain an anode catalyst slurry.

[0054] (2) A certain amount of commercial Pt / C catalyst was weighed, and water, isopropyl alcohol and 5% Nafion solution were added in sequence (Pt / C:Nafion = 1.5:1). The mixture was dispersed in an ultrasonic bath until it was uniformly mixed to obtain a cathode catalyst slurry.

[0055] (3) The polytetrafluoroethylene film was placed on a hot plate and fixed by negative pressure of an air compressor. The temperature of the hot plate was set to 80-90°C. The anode and cathode catalyst slurries were uniformly sprayed on the polytetrafluoroethylene film using a spraying device, and the effective area of the catalyst layer was 2x2 cm 2 .

[0056] (4) The polytetrafluoroethylene film coated with the anode and cathode catalyst layers was placed on both sides of a N115, proton exchange membrane of appropriate size, and a CCM-type membrane electrode was obtained after hot pressing and transfer printing.

[0057] (5) The scanning electron microscope (SEM) image is shown in Figure 2 . The surface of the catalyst layer of the comparative example had obvious cracks due to the poor mechanical stability of the short side chain ionomer catalyst layer.

[0058] (6) The water electrolysis performance of the membrane electrode was tested in an electrolytic cell at 80°C. The experimental results are shown in Table 2. Figure 3 As shown in Table 2, when the current density was 2 A / cm 2 , the electrolysis voltage of the electrolytic cell was 1.851 V. The stability test at a current density of 2 A / cm 2 is shown in Table 3. Figure 4

[0059] Comparative Example 2

[0060] (1) A certain amount of iridium-based catalyst was weighed, and then isopropanol, water, and Nafion solution were added (mass ratio, iridium-based catalyst:Nafion = 4:1). The mixture was dispersed in an ultrasonic bath at low temperature ice water bath until it was uniformly mixed to obtain an anode catalyst slurry.

[0061] (2) A certain amount of commercial Pt / C catalyst was weighed, and then water, isopropanol, and 5% Nafion solution were added (Pt / C:Nafion = 1.5:1). The mixture was dispersed in an ultrasonic bath until it was uniformly mixed to obtain a cathode catalyst slurry.

[0062] (3) A polytetrafluoroethylene membrane was placed on a hot plate and fixed using the negative pressure of an air compressor. The temperature of the hot plate was set to 80-90°C, and a spraying device was used to uniformly spray the anode and cathode catalyst slurries on the polytetrafluoroethylene membrane. The effective area of the catalyst layer was 2x2 cm 2 .

[0063] (4) The polytetrafluoroethylene membrane coated with the anode and cathode catalyst layers was placed on both sides of a N115 proton exchange membrane of appropriate size, and a CCM-type membrane electrode was obtained after hot pressing and transfer printing.

[0064] (5) The water electrolysis performance of the membrane electrode was tested in an electrolytic cell at 80°C. The experimental results are shown in Table 2. Figure 3 As shown in Table 2, when the current density was 2 A / cm 2 , the electrolysis voltage of the electrolytic cell was 1.828 V.

[0065] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be included in the scope of the present application.​

Claims

1. A method for preparing a proton exchange membrane water electrolysis membrane electrode with a hybrid ionomer constructed catalytic layer, characterized in that: Comprising, mixing the oxygen evolution catalyst with long-chain ionomer, short-chain ionomer and solvent, ultrasonic dispersion to uniform, to get mixed layer anode catalyst slurry; mixing the hydrogen evolution catalyst with long-chain ionomer and solvent, ultrasonic dispersion to uniform, to get cathode catalyst slurry; coating the cathode catalyst slurry and anode catalyst slurry to polytetrafluoroethylene film respectively, to get catalytic layer; stacking the above cathode catalytic layer, proton exchange membrane, anode catalytic layer in order, by hot pressing, transfer to the both sides of the proton exchange membrane, to get membrane electrode; the long-chain ionomer is perfluorosulfonic acid ionomer Nafion; the short-chain ionomer is short side chain perfluorosulfonic acid ionomer Aquivion.

2. The production method according to claim 1, characterized by: the oxygen evolution catalyst is iridium-based catalyst.

3. The production method according to claim 1, wherein: the hydrogen evolution catalyst is platinum-based catalyst.

4. The production method according to claim 1, wherein: the solvent is one or more of water, ethanol, isopropanol.

5. The production method according to claim 1, wherein: the mass fraction of the ionomer in the catalytic layer solid is 5%~80%.

6. The production method according to claim 1, wherein: the mass ratio of the oxygen evolution catalyst to the solvent is 1:5~1:

100.

7. The production method according to claim 1, wherein: the temperature of the hot pressing is 120~135 ℃, and the pressure is 10~30 MPa.

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