Phosphoric acid doped high-temperature fuel cell membrane electrode catalyst layer coating process

Abstract

The invention discloses a phosphoric acid doped high-temperature fuel cell membrane electrode catalyst layer coating process. The invention belongs to the technical field of battery membranes, different types of catalyst slurry are respectively coated on a proton exchange membrane and a gas diffusion layer, and a double-layer catalytic structure is formed by hot pressing combination, so that the usage amount of a noble metal catalyst is effectively reduced, and the performance of a membrane electrode is improved; according to the special acidic system slurry coated on the proton exchange membrane, the swelling phenomenon of the proton exchange membrane can be reduced, so that the slurry coating of the proton exchange membrane is realized; under certain temperature and pressure conditions, the catalyst layer on the proton exchange membrane and the catalyst layer on the gas diffusion layer are combined together through the hot press to form a new catalyst layer, and compared with a traditional method that the gas diffusion layer is directly coated with catalyst slurry, the contact resistance of a membrane electrode can be reduced, and the contact resistance of the membrane electrode can be reduced. The usage amount of a noble metal catalyst is reduced, and the performance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery membranes, and specifically refers to a coating process for the catalyst layer of a phosphoric acid-doped high-temperature fuel cell membrane electrode. Background Art

[0002] As an important application form of hydrogen energy, hydrogen fuel cells can directly convert the chemical energy in hydrogen energy into electrical energy, and have the advantages of high energy utilization efficiency, green, environmental protection, zero emission and sustainability, becoming a key technology to solve energy crisis and environmental problems. Due to its relatively high operating temperature (130 - 220 °C), compared with low-temperature fuel cells (usually below 80 °C), the high-temperature proton exchange membrane fuel cell (HT-PEMFC) has advantages such as faster electrode reaction kinetics, stronger resistance to poisoning by impurities in fuel / air, a wide range of fuel sources (such as methanol reformate, industrial by-product hydrogen, etc.), and a simpler water / heat management system. Therefore, HT-PEMFC is regarded as an important frontier development direction of polymer membrane fuel cells.

[0003] The membrane electrode, as the core component of a fuel cell, directly determines the performance of the battery. Especially in the membrane electrode, the catalyst layer plays a crucial role. The quality of the catalyst layer directly affects the overall performance of the membrane electrode. Currently, in the phosphoric acid-doped high-temperature proton exchange membrane fuel cell, the catalyst layer of the membrane electrode is mainly formed by directly coating the catalyst slurry on the gas diffusion layer. This process results in a large contact resistance between the catalyst layer and the proton exchange membrane, thus requiring the use of a large amount of platinum-based noble metal catalysts. However, the high cost of the noble metal platinum (Pt) severely limits the large-scale industrial application of this technology. Therefore, the key to reducing the cost of fuel cells lies in reducing the usage amount of noble metal catalysts, improving the utilization rate of catalysts, and ensuring that the battery performance does not deteriorate under an ultra-low catalyst loading, so as to further reduce its cost and improve market competitiveness.

[0004] To address the above problems, the present invention provides a novel coating process for the catalyst layer of a phosphoric acid-doped high-temperature fuel cell membrane electrode. This process involves separately coating different catalyst slurries on the proton exchange membrane and the gas diffusion layer, and then combining the two parts through a hot pressing method to form a new catalyst layer. This method not only effectively reduces the contact resistance of the membrane electrode, reduces the usage amount of noble metal catalysts, but also significantly improves the overall performance of the membrane electrode. In particular, the catalyst slurry coated on the proton exchange membrane uses an acidic system slurry, which greatly improves the swelling phenomenon of the proton exchange membrane and further enhances the stability and service life of the membrane electrode. Summary of the Invention

[0005] The object of the present invention is to provide a coating process for the catalytic layer of a phosphoric acid-doped high-temperature fuel cell membrane electrode. In view of the technical problems existing in the preparation process of the catalytic layer in the existing phosphoric acid-doped high-temperature proton exchange membrane fuel cell (HT-PEMFC), the present invention proposes an innovative coating process for the catalytic layer of the membrane electrode. This process effectively reduces the usage amount of noble metal catalysts and improves the performance of the membrane electrode by respectively coating different types of catalyst slurries on the proton exchange membrane and the gas diffusion layer and forming a double-layer catalytic structure through hot pressing. The special acidic system slurry coated on the proton exchange membrane can reduce the swelling phenomenon of the proton exchange membrane, thereby realizing the slurry coating on the proton exchange membrane; under certain temperature and pressure conditions, the catalytic layer on the proton exchange membrane and the catalytic layer on the gas diffusion layer are combined together by a hot press to form a new catalytic layer; compared with the traditional method of directly coating the catalyst slurry on the gas diffusion layer, it can achieve the purpose of reducing the contact resistance of the membrane electrode, reducing the usage amount of noble metal catalysts, and improving the performance.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A coating process for the catalytic layer of a phosphoric acid-doped high-temperature fuel cell membrane electrode, the coating process comprising the following steps:

[0007] (1) Prepare cathode catalyst slurry 1 for coating on the proton exchange membrane; prepare anode catalyst slurry 2 for coating on the proton exchange membrane;

[0008] (2) Prepare cathode catalyst slurry 3 for coating on the gas diffusion layer; prepare anode catalyst slurry 4 for coating on the gas diffusion layer;

[0009] (3) Add the prepared catalyst slurry 1 into the ink injector of the doctor blade coater and discharge the air in the pipe;

[0010] (4) Lay the proton exchange membrane flat on the platform of the doctor blade coater and use a vacuum pump to adsorb the proton exchange membrane on the surface of the platform;

[0011] (5) After setting the parameters of the doctor blade coater, start the equipment and perform the first coating on the proton exchange membrane;

[0012] (6) After the first coating is completed, wait for the slurry to dry completely, flip the proton exchange membrane, and use catalyst slurry 2 to repeat steps 3 to 5 to coat the other side of the proton exchange membrane;

[0013] (7) After the slurry on the second side of the proton exchange membrane has also dried completely, remove it and set it aside for later use;

[0014] (8) Add the prepared catalyst slurry 3 into the ink injector of the doctor blade coater and discharge the air in the pipe;

[0015] (9) Lay the gas diffusion layer flat on the platform of the doctor blade coater, and use a vacuum pump to adsorb the gas diffusion layer on the surface of the platform;

[0016] (10) After setting the parameters of the doctor blade coater, start the equipment and coat the gas diffusion layer;

[0017] (11) After the coating is completed, wait for the slurry to dry completely, then remove it for standby. Use the catalyst slurry 4, and repeat steps (8) to (10) to complete the coating of the second gas diffusion layer;

[0018] (12) After assembling the proton exchange membrane and the gas diffusion layer coated with the catalyst slurry as required, perform hot pressing treatment using a hot press. The temperature of the hot press is 100 - 180 °C, the pressure is 0.3 - 5 MPa, and the hot pressing time is 90 - 300 s, and finally obtain a membrane electrode that can be used for the assembly of a hydrogen fuel cell.

[0019] Further, the cathode and anode catalysts in step (1) are at least one of platinum-based noble metal catalysts such as Pt / C, Pt-Co / C, Pt-Ni / C, etc., and the Pt content is 20% - 60%.

[0020] Further, the acidic solvent in step (1) is at least one of organic carboxylic acids such as formic acid, acetic acid, propionic acid, oxalic acid, etc., the solid content range is 1% - 10%, and the I / C is 0.5 - 1.5.

[0021] Further, the ionomer in step (1) is at least one of aromatic heterocyclic polymers containing benzimidazole repeating units in the polymer main chain such as polybenzimidazole, the rotation speed of the high-speed disperser is 5000 rpm - 25000 rpm, the dispersion time is 0.5 - 5 hours, the rotation speed of the ball mill is 100 rpm - 800 rpm, and the ball milling time is 5 - 50 h.

[0022] Further, the cathode and anode catalysts in step (2) are at least one of platinum-based noble metal catalysts such as Pt / C, Pt-Co / C or Pt-Ni / C, etc., and the Pt content is 20% - 60%.

[0023] Further, the solvent in step (2) is at least one of alcohol organic compounds such as n-butanol, isopropanol, n-propanol, etc. and deionized water, the solid content range is 1% - 10%, the I / C is 0.5 - 1.5, and the water-alcohol ratio range is 1 / 5 - 5 / 1.

[0024] Further, the ionomer in the step (2) is at least one of fluororesins such as polychlorotrifluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polyvinyl fluoride. The rotation speed of the high-speed disperser is 5000 rpm to 25000 rpm, the dispersion time is 0.5 to 5 hours, the rotation speed of the ball mill is 100 rpm to 800 rpm, and the ball milling time is 5 to 50 h.

[0025] The beneficial effects achieved by the present invention with the above structure are as follows: (1) By separately coating different types of catalyst slurries on the proton exchange membrane and the gas diffusion layer and forming a double-layer catalytic structure through hot pressing, the present invention effectively reduces the usage amount of the noble metal catalyst and improves the performance of the membrane electrode; (2) The special acidic system slurry coated on the proton exchange membrane can reduce the swelling phenomenon of the proton exchange membrane, thereby realizing the slurry coating of the proton exchange membrane; (3) Under certain temperature and pressure conditions, the catalytic layer on the proton exchange membrane and the catalytic layer on the gas diffusion layer are combined together through a hot press to form a new catalytic layer. Compared with the traditional method of directly coating the catalyst slurry on the gas diffusion layer, it can reduce the contact resistance of the membrane electrode, reduce the usage amount of the noble metal catalyst, and improve the performance. Description of the Drawings

[0026] Figure 1 Process flow chart;

[0027] Figure 2 Polarization curve comparison chart.

[0028] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. Detailed Embodiments

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for illustrative purposes and do not limit the content of the present application.

[0031] In the experimental methods of the following embodiments, unless otherwise specified, they are all conventional methods; in the test materials and test strains used in the following embodiments, unless otherwise specified, they are all obtained by purchasing from commercial channels.

[0032] Example 1

[0033] A Coating Process for the Catalyst Layer of a Phosphoric Acid-Doped High-Temperature Fuel Cell Membrane Electrode

[0034] The coating process includes the following steps:

[0035] (1) Prepare the cathode catalyst slurry for the proton exchange membrane: Take 40% Pt / C catalyst, and successively add acetic acid and polybenzimidazole, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the cathode catalyst slurry is prepared, with a solid content of 3% and I / C of 1.0;

[0036] (2) Prepare the anode catalyst slurry for the proton exchange membrane: Take 30% Pt / C catalyst, and successively add acetic acid and polybenzimidazole, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the cathode catalyst slurry is prepared, with a solid content of 3% and I / C of 1.0;

[0037] (3) Prepare the cathode catalyst slurry for the gas diffusion layer: Take 40% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the anode catalyst slurry is prepared, with a solid content of 3%, I / C of 1.0, and an alcohol-water ratio of 1 / 1. The ratio of isopropanol to n-propanol is 1:1;

[0038] (4) Prepare the anode catalyst slurry for the gas diffusion layer: Take 30% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the anode catalyst slurry is prepared, with a solid content of 3%, I / C of 1.0, and an alcohol-water ratio of 1 / 1. The ratio of isopropanol to n-propanol is 1:1;

[0039] (5) Adopt the doctor blade coating process to scrape the cathode catalyst slurry prepared in step 1 onto a 20-μm-thick proton exchange membrane, and scrape the anode catalyst slurry prepared in step 2 onto the other side of the proton exchange membrane;

[0040] (6) Adopt the doctor blade coating process to scrape the cathode catalyst slurry prepared in step 3 onto the first gas diffusion layer, and scrape the anode catalyst slurry prepared in step 4 onto the second gas diffusion layer; wherein, the total Pt loading in the cathode catalyst slurry is 0.6 mg / cm 2 , and the total Pt loading in the anode catalyst slurry is 0.3 mg / cm 2 ;

[0041] (7) Take out the bilaterally coated proton exchange membrane prepared in step 5, the first gas diffusion layer (cathode diffusion layer) and the second gas diffusion layer (anode diffusion layer) treated in step 6 and place them as required. Adopt the hot pressing process, where the hot pressing temperature is 150 °C, the hot pressing time is 180 s, and the hot pressing pressure is 0.8 MPa. Hot press the cathode diffusion layer and the anode diffusion layer prepared in step 6 onto the bilaterally coated proton exchange membrane prepared in step 5 to obtain a high-temperature fuel cell membrane electrode.

[0042] Example 2

[0043] A Coating Process for the Catalytic Layer of a Phosphoric Acid Doped High-Temperature Fuel Cell Membrane Electrode

[0044] The coating process includes the following steps:

[0045] (1) Prepare the cathode catalyst slurry for the proton exchange membrane: Take 40% Pt / C catalyst, and successively add acetic acid and polybenzimidazole, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the cathode catalyst slurry is prepared, where the solid content is 3% and I / C is 1.0;

[0046] (2) Prepare the anode catalyst slurry for the proton exchange membrane: Take 30% Pt / C catalyst, and successively add acetic acid and polybenzimidazole, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the cathode catalyst slurry is prepared, where the solid content is 3% and I / C is 1.0;

[0047] (3) Prepare the cathode catalyst slurry for the gas diffusion layer: Take 40% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride, and disperse at high speed. The rotation speed of the high-speed disperser is 10,000 rpm, and the dispersion time is 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm. After 15 hours of ball milling and dispersion, the anode catalyst slurry is prepared, where the solid content is 3%, I / C is 1.0, the alcohol-water ratio is 1 / 1, and the ratio of isopropanol to n-propanol is 1:1;

[0048] (4) Prepare the anode catalyst slurry for the gas diffusion layer: Take 30% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride. Disperse at high speed with the high-speed disperser rotating at 10,000 rpm for 1 hour. Then put it into a ball mill rotating at 300 rpm and disperse by ball milling for 15 hours to obtain the anode catalyst slurry, with a solid content of 3%, I / C of 1.0, an alcohol-to-water ratio of 1 / 1, and the ratio of isopropanol to n-propanol being 1:1;

[0049] (5) Using the doctor blade coating process, scrape the cathode catalyst slurry prepared in step 1 onto a 20-μm-thick proton exchange membrane, and scrape the anode catalyst slurry prepared in step 2 onto the other side of the proton exchange membrane;

[0050] (6) Using the doctor blade coating process, scrape the cathode catalyst slurry prepared in step 3 onto the first gas diffusion layer, and scrape the anode catalyst slurry prepared in step 4 onto the second gas diffusion layer; among them, the total Pt loading in the cathode catalyst slurry is 0.5 mg / cm 2 , and the total Pt loading in the anode catalyst slurry is 0.25 mg / cm 2 ;

[0051] (7) Take out the double-sided coated proton exchange membrane prepared in step 5, the first gas diffusion layer (cathode diffusion layer) and the second gas diffusion layer (anode diffusion layer) processed in step 6 and place them as required. Using the hot pressing process, with a hot pressing temperature of 150 °C, a hot pressing time of 180 s, and a hot pressing pressure of 0.8 MPa, hot press the cathode diffusion layer and the anode diffusion layer prepared in step 6 onto the double-sided coated proton exchange membrane prepared in step 5 to obtain a high-temperature fuel cell membrane electrode.

[0052] Example 3

[0053] A Coating Process for the Catalytic Layer of a Phosphoric Acid-Doped High-Temperature Fuel Cell Membrane Electrode

[0054] The coating process includes the following steps:

[0055] (1) Prepare the cathode catalyst slurry for the proton exchange membrane: Take 40% Pt / C catalyst, and successively add acetic acid and polybenzimidazole. Disperse at high speed with the high-speed disperser rotating at 10,000 rpm for 1 hour. Then put it into a ball mill rotating at 300 rpm and disperse by ball milling for 15 hours to obtain the cathode catalyst slurry, with a solid content of 3% and I / C of 1.0;

[0056] (2) Prepare the anode catalyst slurry for the proton exchange membrane: Take 30% Pt / C catalyst, and successively add acetic acid and polybenzimidazole, then disperse at high speed with the high-speed disperser rotating at 10,000 rpm for 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm and disperse by ball milling for 15 hours to prepare the cathode catalyst slurry, with a solid content of 3% and I / C of 1.0;

[0057] (3) Prepare the cathode catalyst slurry for the gas diffusion layer: Take 40% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride, then disperse at high speed with the high-speed disperser rotating at 10,000 rpm for 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm and disperse by ball milling for 15 hours to prepare the anode catalyst slurry, with a solid content of 3%, I / C of 1.0, an alcohol-water ratio of 1 / 1, and the ratio of isopropanol to n-propanol being 1:1;

[0058] (4) Prepare the anode catalyst slurry for the gas diffusion layer: Take 30% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride, then disperse at high speed with the high-speed disperser rotating at 10,000 rpm for 1 hour. Then put it into a ball mill with a rotation speed of 300 rpm and disperse by ball milling for 15 hours to prepare the anode catalyst slurry, with a solid content of 3%, I / C of 1.0, an alcohol-water ratio of 1 / 1, and the ratio of isopropanol to n-propanol being 1:1;

[0059] (5) Adopt the doctor blade coating process to scrape the cathode catalyst slurry prepared in step 1 onto a 20-μm-thick proton exchange membrane, and scrape the anode catalyst slurry prepared in step 2 onto the other side of the proton exchange membrane;

[0060] (6) Adopt the doctor blade coating process to scrape the cathode catalyst slurry prepared in step 3 onto the first gas diffusion layer, and scrape the anode catalyst slurry prepared in step 4 onto the second gas diffusion layer; among them, the total Pt loading in the cathode catalyst slurry is 0.4 mg / cm 2 , and the total Pt loading in the anode catalyst slurry is 0.2 mg / cm 2 ;

[0061] (7) Take out the bilaterally coated proton exchange membrane prepared in step 5, the first gas diffusion layer (cathode diffusion layer) and the second gas diffusion layer (anode diffusion layer) processed in step 6 and place them as required. Adopt the hot pressing process, with a hot pressing temperature of 150 °C, a hot pressing time of 180 s, and a hot pressing pressure of 0.8 MPa. Hot press the cathode diffusion layer and the anode diffusion layer prepared in step 6 onto the bilaterally coated proton exchange membrane prepared in step 5 to obtain the high-temperature fuel cell membrane electrode.

[0062] Comparative Example 1

[0063] A Coating Process for the Catalyst Layer of a Phosphoric Acid-Doped High-Temperature Fuel Cell Membrane Electrode

[0064] The coating process includes the following steps:

[0065] (1) Prepare the cathode catalyst slurry for the gas diffusion layer: Take 40% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride. Disperse at high speed with a high-speed disperser at a speed of 10,000 rpm for 1 hour. Then put it into a ball mill at a speed of 300 rpm and disperse for 15 hours to prepare the anode catalyst slurry, with a solid content of 3%, I / C of 1.0, an alcohol-to-water ratio of 1 / 1, and the ratio of isopropanol to n-propanol being 1:1;

[0066] (2) Prepare the anode catalyst slurry for the gas diffusion layer: Take 30% Pt / C catalyst, and successively add deionized water, isopropanol, n-propanol, and polyvinylidene fluoride. Disperse at high speed with a high-speed disperser at a speed of 10,000 rpm for 1 hour. Then put it into a ball mill at a speed of 300 rpm and disperse for 15 hours to prepare the anode catalyst slurry, with a solid content of 3%, I / C of 1.0, an alcohol-to-water ratio of 1 / 1, and the ratio of isopropanol to n-propanol being 1:1;

[0067] (3) Adopt the doctor blade coating process to scrape the cathode catalyst slurry prepared in step 1 onto the first gas diffusion layer. Among them, the total Pt loading in the cathode catalyst slurry is 1.5 mg / cm 2 ;

[0068] (4) Adopt the doctor blade coating process to scrape the anode catalyst slurry prepared in step 2 onto the second gas diffusion layer; among them, the total Pt loading in the anode catalyst slurry is 0.8 mg / cm 2 ;

[0069] (5) Take out the first gas diffusion layer (cathode diffusion layer) treated in step 3 and the second gas diffusion layer (anode diffusion layer) treated in step 4 and place them as required. Adopt the hot pressing process, with a hot pressing temperature of 150 °C, a hot pressing time of 180 s, and a hot pressing pressure of 0.8 MPa. Hot press the cathode diffusion layer prepared in step 3 and the anode diffusion layer prepared in step 4 onto a 20-μm-thick proton exchange membrane to obtain a high-temperature fuel cell membrane electrode.

[0070] Experimental Example 1

[0071] Using the high-temperature fuel cell membrane electrodes prepared in Example 1, Example 2, Example 3 and Comparative Example 1 as experimental materials, hydrogen fuel cells were prepared and divided into Example 1-3 groups and Comparative Example 1 group. The battery to be tested was assembled in the correct manner and installed on the test fixture to ensure that the electrode was firmly connected to the fixture and avoid test errors caused by poor contact. The working electrode, reference electrode and auxiliary electrode were respectively connected to the corresponding interfaces of the electrochemical workstation or potentiostat. The test equipment was started and potential scanning was carried out according to the set parameters. During the scanning process, the equipment would automatically record the current values at different potentials, so as to obtain the relationship data between current and potential. The current and potential data obtained from the test were imported into the data processing software, and the polarization curve was plotted with the potential as the abscissa and the current density (current divided by the electrode area) as the ordinate.

[0072] Result analysis: When the platinum loadings on the cathode and anode in the Example 1-3 groups were lower than those in Comparative Example 1 group, the overall performance of the hydrogen fuel cell was still better than that of Comparative Example, and the effect was obvious.

[0073] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0074] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar structural modes and embodiments without creative work without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process, characterized in that: The coating process comprises the following steps: (1) preparing cathode catalyst slurry 1 for coating of proton exchange membrane; preparing anode catalyst slurry 2 for coating of proton exchange membrane; (2) preparing cathode catalyst slurry 3 for gas diffusion layer coating; preparing anode catalyst slurry 4 for gas diffusion layer coating; (3) Add the prepared catalyst slurry 1 into the ink injector of the blade coater and exhaust the air in the tube; (4) Laying the proton exchange membrane flat on the platform of the doctor blade coater, and using a vacuum pump to adsorb the proton exchange membrane on the platform surface; (5) After setting the parameters of the blade coater, start the equipment and perform the first coating on the proton exchange membrane; (6) After the first coating is completed, wait until the slurry is completely dry, turn the proton exchange membrane over, use catalyst slurry 2, repeat steps (3) to (5) to coat the other side of the proton exchange membrane; (7) After the slurry on the second side of the proton exchange membrane is completely dried, remove it for later use; (8) Add the prepared catalyst slurry 3 into the ink injector of the blade coater and exhaust the air in the tube; (9) Spread the gas diffusion layer flat on the platform of the blade coater and use a vacuum pump to adsorb the gas diffusion layer on the platform surface; (10) After setting the parameters of the blade coater, start the equipment and coat the gas diffusion layer; (11) After the coating is completed, the slurry is completely dried and removed for use, and catalyst slurry 4 is used and steps (8) to (10) are repeated to complete the coating of the second gas diffusion layer; (12) After the proton exchange membrane and gas diffusion layer coated with the catalyst slurry are assembled as required, a hot press is used for hot pressing. The hot press temperature is 100 to 180° C., the pressure is 0.3 to 5 MPa, and the hot pressing time is 90 to 300 s, and finally a membrane electrode that can be used for hydrogen fuel cell assembly is obtained.

2. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 1, characterized in that: The cathode and anode catalysts in step (1) are at least one of platinum-based precious metal catalysts such as Pt / C, Pt-Co / C, Pt-Ni / C, etc., and the Pt content is 20% to 60%.

3. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 2, characterized in that: The acidic solvent in step (1) is at least one of organic carboxylic acids such as formic acid, acetic acid, propionic acid, oxalic acid, etc., with a solid content ranging from 1% to 10% and an I / C of 0.5 to 1.

5.

4. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 3, characterized in that: The ionomer in step (1) is at least one of aromatic heterocyclic polymers containing benzimidazole repeating units in the polymer main chain such as polybenzimidazole, the high-speed disperser speed is 5000rpm-25000rpm, the dispersion time is 0.5-5 hours, the ball mill speed is 100rpm-800rpm, and the ball milling time is 5-50h.

5. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 4, characterized in that: The cathode and anode catalysts in step (2) are at least one of platinum-based precious metal catalysts such as Pt / C, Pt-Co / C or Pt-Ni / C, and the Pt content is 20% to 60%.

6. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 5, characterized in that: The solvent in step (2) is at least one of an alcohol organic compound such as n-butanol, isopropanol, and n-propanol and deionized water, with a solid content ranging from 1% to 10%, an I / C of 0.5 to 1.5, and a water-to-alcohol ratio ranging from 1 / 5 to 5 / 1.

7. A phosphoric acid-doped high-temperature fuel cell membrane electrode catalyst layer coating process according to claim 6, characterized in that: The ionomer in step (2) is at least one of fluororesins such as polytrifluorochloroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-trifluorochloroethylene copolymer, and polyvinyl fluoride. The high-speed disperser has a speed of 5000 rpm to 25000 rpm, a dispersion time of 0.5 to 5 hours, a ball mill has a speed of 100 rpm to 800 rpm, and a ball milling time of 5 to 50 hours.

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