Anti-reverse electrode, preparation method thereof and membrane electrode

Abstract

The invention discloses an anti-reverse electrode, a preparation method thereof and a membrane electrode, and the preparation method of the anti-reverse electrode comprises the following steps: dispersing titanium oxide in isopropanol to obtain a first mixed solution; mixing the first mixed solution with a Nafion resin solution to obtain a second mixed solution, and performing vacuum drying on the second mixed solution to obtain a Nafion resin-titanium oxide compound; putting the Nafion resin-titanium oxide compound and a platinum-carbon catalyst into a ball-milling tank according to a preset proportion, and carrying out ball-milling treatment to obtain mixed slurry; a preset carrier is coated with the mixed slurry in a blade coating mode, an anti-reverse-pole catalyst layer is formed on the preset carrier, and the anti-reverse-pole electrode is obtained. The Nafion resin-titanium oxide compound is introduced, stable perfluorinated sulfonic acid resin and a pore network are constructed, an efficient transmission path can be provided for protons and gas, the influence of catalyst degradation and structure change on performance is reduced, and the overall efficiency of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of fuel cell membrane electrode technology, and in particular to an anti-reverse electrode and its preparation method, and a membrane electrode. Background Technology

[0002] If anode starvation (such as insufficient hydrogen supply) occurs on the anode side of a fuel cell, the anode potential will immediately rise from near 0 V to above 1.5 V, resulting in the so-called reverse polarity phenomenon. At this time, although the water on the anode side will undergo electrolysis, the carbon support cannot withstand such a high potential, causing the carbon support structure to collapse and corrode, and leading to the shedding and loss of platinum catalyst particles, posing a great threat to the performance and lifespan of the fuel cell itself.

[0003] Currently, most solutions for reverse polarity on the anode side involve introducing anti-reverse polarity catalysts, such as IrO2, RuO2, or iridium-ruthenium alloy catalysts. These catalysts utilize their water electrolysis activity to delay the occurrence of reverse polarity, essentially delaying the potential from further increasing. However, the electrolysis potential of water on the IrO2 or RuO2 surface is typically around 1.5 V to 1.6 V vs. RHE, where a significant water electrolysis current can be observed. Carbon corrosion, on the other hand, begins at a potential of 1.0 V. Therefore, despite the addition of anti-reverse polarity catalysts, carbon corrosion remains a problem. Consequently, carbon corrosion in traditional electrodes leads to the simultaneous collapse of the triple network (electrons, protons, and gas), which is the fundamental cause of the rapid performance degradation. Summary of the Invention

[0004] This application provides an anti-reverse electrode and its preparation method, as well as a membrane electrode. By introducing Nafion resin-titanium oxide composite, a stable perfluorosulfonic acid resin and pore network are constructed, which can provide an efficient transport path for protons and gases, reduce the impact of catalyst degradation and structural changes on performance, and improve the overall efficiency of the battery.

[0005] On one hand, this application provides a method for preparing a reverse polarity electrode, the method comprising: Titanium oxide was dispersed in isopropanol to obtain the first mixed solution; The first mixed solution was mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution was vacuum dried to obtain Nafion resin-titanium oxide composite. The Nafion resin-titanium oxide composite and platinum-carbon catalyst were placed in a ball mill jar and ball milled in a preset ratio to obtain a mixed slurry. The mixed slurry is coated onto a preset carrier to form an anti-reverse electrode catalytic layer, thereby obtaining the anti-reverse electrode.

[0006] Furthermore, the titanium oxide includes one or more of titanium monoxide, titanium dioxide, and titanium trioxide; The particle size of the titanium oxide is 10 nm-35 nm; The pH value of the first mixed solution is 2-3.

[0007] Furthermore, the concentration of the Nafion resin solution is 20%; The solid content of the mixed slurry is 18%-22%; The preset ratio is 0.5-1.5, which represents the mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the carbon support in the platinum-carbon catalyst.

[0008] Further, the step of coating the mixed slurry onto a predetermined carrier to form an anti-reverse electrode catalytic layer on the predetermined carrier, thereby obtaining the anti-reverse electrode, includes: The mixed slurry is scraped onto the preset carrier at a preset scraping rate to obtain an initial scraped sample; The initial coated sample is left to stand at a preset temperature, and then dried to obtain the anti-reverse electrode.

[0009] Furthermore, the preset coating rate is 10 mm / s-15 mm / s; The thickness of the mixed slurry coated on the preset carrier is 80 μm-120 μm; The preset temperature is 40℃-48℃; The drying process is carried out at a temperature of 75℃-85℃.

[0010] Further, the first mixed solution is mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution is vacuum dried to obtain a resin-titanium oxide composite, comprising: The first mixed solution is mixed with the Nafion resin solution and stirred at room temperature to obtain a stirred solution; The stirred solution was allowed to stand at room temperature until the second mixed solution was obtained. The second mixed solution was subjected to vacuum drying to obtain the resin-titanium oxide composite.

[0011] Furthermore, the stirring treatment lasts for 10-15 minutes, and the settling time lasts for 6-20 hours. The vacuum drying temperature is 50℃-150℃.

[0012] Further, the step of placing the Nafion resin-titanium oxide composite and the platinum-carbon catalyst in a ball mill jar at a preset ratio for ball milling to obtain a mixed slurry includes: The Nafion resin-titanium oxide composite and the platinum-carbon catalyst were placed in the ball mill jar according to the preset ratio, and ethanol, n-propanol and deionized water were added for ball milling to obtain the mixed slurry. The ball milling process takes 5-12 hours and the ball milling speed is 300-900 rpm. The ratio of ethanol, n-propanol and deionized water is 1:1:2.

[0013] On the other hand, an anti-reverse electrode is provided, which is prepared by the above-described method for preparing an anti-reverse electrode.

[0014] On the other hand, a membrane electrode is provided, which includes the anti-reverse electrode as described above.

[0015] The anti-reverse electrode, its preparation method, and the membrane electrode provided in this application have the following technical advantages: This application disperses titanium oxide in isopropanol to obtain a first mixed solution; mixes the first mixed solution with a Nafion resin solution to obtain a second mixed solution, and vacuum dries the second mixed solution to obtain a Nafion resin-titanium oxide composite; places the Nafion resin-titanium oxide composite and a platinum-carbon catalyst in a ball mill jar according to a preset ratio for ball milling to obtain a mixed slurry; and coats the mixed slurry onto a preset support to form an anti-reverse electrode catalytic layer on the preset support to obtain an anti-reverse electrode. This application, by introducing a Nafion resin-titanium oxide composite, can retain the highly active Pt / C catalyst and construct a sustainable proton conduction network and physical structural support independent of the carbon support. The rigid Nafion resin-titanium oxide composite particles are distributed between the Pt / C particles, which can prevent the complete collapse of the pores after carbon corrosion and maintain the gas transport path. By controlling the pH value of the titanium metal oxide solution and then mixing it with the Nafion resin solution, followed by stirring and standing, the titanium metal oxide particles and Nafion resin can be more tightly bonded to form a more stable structure. Ball milling can achieve more uniform mixing of the Nafion resin-titanium oxide composite powder and the platinum-carbon catalyst. A uniformly dispersed slurry is obtained, and then coated onto the surface of a pre-set carrier by a scraping method to form an anode catalyst layer. The Nafion resin in the anode catalyst layer is independent of the carbon carrier, which can avoid the migration and aggregation of traditional resins after carbon corrosion, thereby constructing a stable proton transport network. In this anode catalyst layer, titanium oxide particles can form a "scaffold" between Pt / C nanoparticles, and even if carbon corrosion occurs, the porous network can still be preserved, ensuring the proton and gas transport channels, maintaining the integrity of the porous structure, and improving the working efficiency of the battery. In addition, the preparation method is simple, only requiring the Nafion resin-titanium oxide composite in the anode slurry, without the need to develop new carriers, making it easy to promote industrialization.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart illustrating a method for preparing an anti-reverse electrode provided in the embodiments of this specification; Figure 2This is a schematic diagram of a process for preparing Nafion resin-titanium oxide composites provided in the embodiments of this specification; Figure 3 This is a schematic diagram of a process for preparing an anti-reverse electrode by scraping a mixed slurry, as provided in the embodiments of this specification. Figure 4 This is a polarization curve of a membrane electrode containing a resin-titanium oxide composite before and after reverse polarization, provided in the embodiments of this specification. Figure 5 This is a polarization curve of a membrane electrode containing an anti-reverse catalyst, iridium oxide, before and after reverse polarization, provided in the embodiments of this specification. Detailed Implementation

[0019] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The following describes a method for preparing an anti-reverse electrode according to this application, specifically as follows: Figure 1 As shown, the method may include: S1: Disperse titanium oxide in isopropanol to obtain the first mixed solution; S2: The first mixed solution is mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution is vacuum dried to obtain Nafion resin-titanium oxide composite. S3: The Nafion resin-titanium oxide composite and platinum carbon catalyst are placed in a ball mill jar according to a preset ratio and ball milled to obtain a mixed slurry; S4: The mixed slurry is coated onto a preset carrier to form an anti-reverse electrode catalytic layer on the preset carrier, thereby obtaining the anti-reverse electrode.

[0021] Nafion resin (Nafion-H) is a type of perfluorosulfonic acid resin, copolymerized from tetrafluoroethylene and perfluorovinyl ether monomers containing sulfonic acid groups. It possesses a perfluorocarbon backbone and sulfonic acid side chains, forming a three-phase microstructure where a hydrophobic perfluoro backbone and hydrophilic sulfonic acid ion clusters coexist. Ion and water molecule transport is achieved between ion clusters through channels, exhibiting both ion exchange and proton conduction capabilities. To address the corrosion problem of the catalyst layer on the anode side of hydrogen fuel cells, this application introduces a Nafion resin-titanium oxide composite as a third component to construct a sustainable proton conduction network and physical structural support independent of the carbon support. The rigid Nafion resin-titanium oxide composite particles are distributed between Pt / C, preventing complete collapse of the pores after carbon corrosion and maintaining the gas transport path.

[0022] In this embodiment, titanium oxide, i.e., titanium metal oxide particle powder, is first dispersed in isopropanol, and the pH is adjusted by adding isopropanol until the pH is between 2 and 3 to obtain a first mixed solution. This first mixed solution is then mixed with Nafion resin solution to obtain a second mixed solution, which yields Nafion resin-titanium oxide composite powder. The Nafion resin-titanium oxide composite is then used to prepare a slurry. The Nafion resin-titanium oxide composite and a platinum-carbon catalyst (TKK catalyst, 50% Pt) are placed in a ball mill jar, and a preset solvent is added sequentially. After ball milling, a mixed slurry is obtained. This ball-milled mixed slurry serves as the anode slurry. The mixed slurry is then coated onto a preset support to form an anode catalyst layer, i.e., the aforementioned anti-reverse electrode catalyst layer, to obtain an anti-reverse electrode. This anti-reverse electrode can be used as the anode in a membrane electrode. By adding the Nafion resin-titanium oxide composite to construct a three-component anode, the structural collapse problem caused by carbon corrosion of traditional anodes is solved while retaining the highly active Pt / C catalyst, achieving a dual improvement in "initial performance + corrosion resistance".

[0023] Furthermore, the titanium oxide includes one or more of titanium monoxide, titanium dioxide, and titanium trioxide; The particle size of the titanium oxide is 10 nm-35 nm; The pH value of the first mixed solution is 2-3.

[0024] For example, the titanium oxides mentioned above, i.e. titanium metal oxides, include but are not limited to one or more of titanium monoxide, titanium dioxide, and titanium trioxide, and the particle size of the titanium oxides is between 10 nm and 35 nm.

[0025] For example, when dispersing titanium oxide powder particles in isopropanol, the pH can be adjusted by continuously adding isopropanol until the pH of the solution is between 2 and 3, thus obtaining the first mixed solution described above. The isoelectric point (IEP) of titanium oxide is approximately 6.5. When the solution pH is < 6.5 (such as pH 2-3 in this process), the TiO2 surface carries a positive charge (forming ≡Ti-OH2). + Nafion ionomer particles, due to their sulfonate (-SO3) groups... - The Nafion ionic polymer carries a negative charge in solution. By adjusting the pH to strong acidity, TiO2 becomes positively charged. Through strong electrostatic adsorption, the negatively charged Nafion ionic polymer can uniformly and firmly coat the surface of TiO2 particles, forming a stable "core-shell" structure, rather than just a physical mixture.

[0026] In this embodiment of the application, by controlling the particle size of titanium metal oxide and the pH value of the first mixed solution, the titanium metal oxide and Nafion resin can be more tightly bonded to form a stable "core-shell" structure.

[0027] Furthermore, the concentration of the Nafion resin solution is 20%; The solid content of the mixed slurry is 18%-22%; The preset ratio is 0.5-1.5, which represents the mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the carbon support in the platinum-carbon catalyst.

[0028] For example, the concentration of the Nafion resin solution is 20%, and the solid content of the mixed slurry is 18%-22%, preferably 20%.

[0029] For example, the preset ratio is 0.5-1.5, that is, the mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the carbon support in the platinum carbon catalyst is 0.5-1.5.

[0030] In this embodiment, the prepared Nafion resin-titanium oxide composite is added during the preparation of the anode slurry. The Nafion resin is independent of the carbon support, which can avoid the migration and aggregation of traditional resins after carbon corrosion, thus constructing a stable proton transport network. Furthermore, the titanium oxide particles can form a "scaffold" between the Pt / C nanoparticles, so that even if carbon corrosion occurs, the pore network can still be preserved, ensuring the proton and gas transport channels and maintaining the integrity of the porous structure.

[0031] Furthermore, the solution provided in this application is simple in process, requiring only the addition of an additive, namely Nafion resin-titanium oxide composite, to the anode slurry. It does not require the development of new carriers and is easy to promote industrially, providing key technical support for the large-scale application of PEMFC (Proton Exchange Membrane Fuel Cell) in fuel cell vehicles and other fields.

[0032] Furthermore, such as Figure 2 As shown, the first mixed solution is mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution is vacuum dried to obtain a resin-titanium oxide composite, comprising: S21: The first mixed solution is mixed with the Nafion resin solution and stirred at room temperature to obtain a stirred solution; S22: Let the stirred solution stand at room temperature until the second mixed solution is obtained; S23: The second mixed solution is vacuum dried to obtain the resin-titanium oxide composite.

[0033] Furthermore, the stirring treatment lasts for 10-15 minutes, and the settling time lasts for 6-20 hours. The vacuum drying temperature is 50℃-150℃.

[0034] For example, the first mixed solution described above is mixed with 20% Nafion resin solution and stirred at room temperature for 10-15 minutes. After stirring, the mixture is allowed to stand for 6-20 hours. After standing, it is then vacuum dried at 50-150°C to obtain the resin-titanium oxide composite. The standing after stirring allows the Nafion resin to uniformly coat the titanium oxide.

[0035] In one possible embodiment, the first mixed solution is mixed with a 20% Nafion resin solution, stirred at room temperature for 15 min, allowed to stand for 12 h after stirring, and then vacuum dried at 50℃-150℃ to obtain resin-titanium oxide composite powder.

[0036] In this embodiment, the pH value of the first mixed solution is controlled, and then it is mixed with the Nafion resin solution. After stirring and standing, the titanium metal oxide particles are more tightly bonded to the Nafion resin to form a more stable structure. This allows the rigid Nafion-titanium metal oxide particles to be distributed between Pt / C when preparing the mixed slurry, preventing the pores from completely collapsing after carbon corrosion and maintaining the gas transport path.

[0037] Furthermore, the step of placing the Nafion resin-titanium oxide composite and the platinum-carbon catalyst in a ball mill jar at a preset ratio for ball milling to obtain a mixed slurry includes: The Nafion resin-titanium oxide composite and the platinum-carbon catalyst were placed in the ball mill jar according to the preset ratio, and ethanol, n-propanol and deionized water were added for ball milling to obtain the mixed slurry. The ball milling process takes 5-12 hours and the ball milling speed is 300-900 rpm. The ratio of ethanol, n-propanol and deionized water is 1:1:2.

[0038] For example, the prepared Nafion resin-titanium oxide composite powder and platinum carbon catalyst are placed in a ball mill jar, and then ethanol, n-propanol and deionized water are added for ball milling to obtain a mixed slurry, which is used as the anode slurry for electrode preparation.

[0039] For example, the above ball milling process can be performed using a planetary ball mill, with a milling time of 5 h-12 h, a milling speed of 300 rpm-900 rpm, using zirconia milling balls, and an addition ratio of ethanol, n-propanol and deionized water of 1:1:2.

[0040] In one possible embodiment, Nafion resin-titanium oxide composite powder and platinum-carbon catalyst (TKK catalyst, 50% Pt) are added to a ball mill jar. The mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the carbon support in the platinum-carbon catalyst is between 0.5 and 1.5. Then, ethanol, n-propanol and deionized water are added in a mass ratio of 1:1:2. The mixture is ball-milled at 300 rpm to 900 rpm for 5 h to 12 h to obtain a mixed slurry.

[0041] In this embodiment, ball milling enables a more uniform mixing of Nafion resin-titanium oxide composite powder and platinum-carbon catalyst. By adding Nafion resin-titanium oxide composite to construct a three-component anode, the structural collapse problem caused by carbon corrosion in traditional anodes is solved while retaining the highly active Pt / C catalyst. The titanium metal oxide particles can form a "scaffold" between Pt / C nanoparticles, and even if carbon corrosion occurs, the porous network can still be retained, ensuring the proton and gas transport channels and maintaining the integrity of the porous structure, thereby improving the working efficiency of the battery.

[0042] Furthermore, such as Figure 3 As shown, the step of coating the mixed slurry onto a preset carrier to form an anti-reverse electrode catalytic layer on the preset carrier includes: S41: The mixed slurry is applied to the preset carrier at a preset application rate to obtain an initial coated sample; S42: The initial coated sample is left to stand at a preset temperature, and then dried to obtain the anti-reverse electrode.

[0043] Furthermore, the preset scraping rate is 10 mm / s-15 mm / s; The thickness of the mixed slurry coated on the preset carrier is 80 μm-120 μm; The preset temperature is 40℃-48℃; The drying process is carried out at a temperature of 75℃-85℃.

[0044] For example, during the scraping process, the mixed slurry can be scraped onto a preset carrier at a preset scraping rate. After the scraping is completed, an initial scraped sample is obtained and left to stand. After the mixed slurry on the surface of the preset carrier is significantly dried, the initial scraped sample is placed in an oven for drying to completely remove the solvent and obtain an anti-reverse electrode.

[0045] For example, the preset coating rate can be 10 mm / s-15 mm / s, preferably 15 mm / s; the coating thickness of the mixed slurry on the preset carrier is 80 μm-120 μm, preferably 100 μm; the preset temperature is 40℃-48℃, preferably 45℃; and the temperature for drying the initial coated sample can be 75℃-85℃, preferably 80℃.

[0046] In one possible embodiment, the aforementioned pre-set carrier can be a PTFE membrane cloth, the coating can be done using a Kejing coating machine with a coating speed of 15 mm / s, the wet film thickness produced by the doctor blade is 100 μm, and the hot stage drying temperature is set to 45°C to promote solvent evaporation.

[0047] In one possible embodiment, the hot drying temperature is set to 45°C, and the above-mentioned mixed slurry is scraped onto the PTFE membrane at a scraping rate of 15 mm / s, with a scraping thickness of 100 μm. After the mixed slurry on the preset carrier is significantly dried (about 3 minutes), it is transferred to an oven at 80°C for drying to completely remove the solvent and obtain the anti-reverse electrode.

[0048] In this embodiment, a mixed slurry is coated onto the surface of a pre-set support by a scraping method to form an anodic catalyst layer. This retains the highly active platinum-carbon catalyst, eliminating the need to develop new supports. Furthermore, the coated Nafion resin is independent of the carbon support, avoiding the migration and aggregation of traditional resins after carbon corrosion. This constructs a stable proton transport network. In this anodic catalyst layer, titanium oxide particles can form a "scaffold" between Pt / C nanoparticles, preserving the pore network even after carbon corrosion, ensuring proton and gas transport channels, and maintaining the integrity of the porous structure.

[0049] This application embodiment, by controlling parameters such as the scraping rate and temperature, can more evenly coat the mixed slurry onto the surface of the preset carrier. After coating, it is allowed to stand at a certain temperature before being transferred to an oven for drying. This avoids the slurry from flowing immediately after coating, which would cause uneven slurry thickness distribution on the surface of the preset carrier.

[0050] This application's embodiments, by introducing a Nafion resin-titanium oxide composite, can retain the highly active Pt / C catalyst and construct a sustainable proton conduction network and physical structural support independent of the carbon support. The rigid Nafion resin-titanium oxide composite particles distributed between the Pt / C particles can prevent the pores from completely collapsing after carbon corrosion, maintaining the gas transport path. By controlling the pH value of the titanium metal oxide solution before mixing it with the Nafion resin solution, and then allowing it to stand after stirring, the titanium metal oxide particles can be more tightly bonded to the Nafion resin, forming a more stable structure. Ball milling ensures more uniform mixing of the Nafion resin-titanium oxide composite powder and the platinum-carbon catalyst. The mixture is uniformly dispersed and then coated onto a pre-designed carrier surface by a scraping method to form an anode catalyst layer. The Nafion resin in the anode catalyst layer is independent of the carbon carrier, which can avoid the migration and aggregation of traditional resins after carbon corrosion, thereby constructing a stable proton transport network. In this anode catalyst layer, titanium oxide particles can form a "scaffold" between Pt / C nanoparticles, and even if carbon corrosion occurs, the porous network can still be preserved, ensuring the proton and gas transport channels, maintaining the integrity of the porous structure, and improving the working efficiency of the battery. In addition, the preparation method is simple, requiring only the Nafion resin-titanium oxide composite in the anode slurry, without the need to develop new carriers, making it easy to promote industrialization.

[0051] This application also provides an anti-reverse electrode, which is obtained by the anti-reverse electrode preparation method described above. This anti-reverse electrode can be used as an anode. By introducing Nafion resin-titanium oxide composite, a more optimized porous structure is constructed, providing an efficient path for proton and gas transport.

[0052] This application also provides a membrane electrode comprising the anti-reverse electrode as described above. Because the anti-reverse electrode containing Nafion resin-titanium oxide composite is introduced as the anode, the structure of the Nafion resin-titanium oxide anode is less affected when facing carbon corrosion. By constructing a stable perfluorosulfonic acid resin and pore network, the impact of catalyst degradation and structural changes on performance is reduced, allowing protons and gases to be transported more smoothly and improving the overall efficiency of the battery.

[0053] Example 1: Titanium oxide particles of 10 nm to 35 nm were dispersed in isopropanol solvent and the pH was adjusted to 2-3 to obtain a first mixed solution. The first mixed solution was then stirred with a 20% Nafion ion exchange resin solution for 10 to 15 minutes and allowed to stand overnight for 12 hours. After that, the solution was vacuum dried at 50°C to 150°C to obtain resin-titanium oxide composite powder. Nafion resin-titanium oxide composite powder and platinum carbon catalyst (TKK catalyst, 50% Pt) were added to a ball mill jar. The mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the mass ratio of carbon support in the platinum carbon catalyst was between 0.5 and 1.5. Ethanol, n-propanol and deionized water were then added in a ratio of 1:1:2. The mixture was ball-milled at 300 rpm to 900 rpm for 5 h to 12 h to obtain a mixed slurry. The above-mentioned mixed slurry was coated onto the PTFE membrane at a coating speed of 15 mm / s, with a coating thickness of 100 μm. After the mixed slurry on the preset carrier was clearly dried (about 3 minutes), it was transferred to an oven at 80°C for drying to completely remove the solvent and obtain the anti-reverse electrode.

[0054] The above-mentioned anti-reverse electrode is used as the anode electrode and assembled with the cathode electrode to obtain a membrane electrode.

[0055] Comparative Example 1: Platinum-carbon catalyst (TKK catalyst, 50% Pt) and anti-reverse catalyst iridium oxide (TKK, 76%) were added to a ball mill jar. The mass ratio of platinum in the platinum-carbon catalyst to iridium in the iridium oxide was 2, i.e., Pt / Ir=2. Ethanol, n-propanol and deionized water were added in a ratio of 1:1:2. The mixture was ball-milled at 300 rpm-900 rpm for 5 h-12 h to obtain a slurry containing iridium oxide. The slurry containing iridium oxide was coated onto a PTFE membrane at a coating speed of 15 mm / s to a coating thickness of 100 μm. After the slurry on the preset carrier was visibly dried (about 3 minutes), it was transferred to an oven at 80°C for drying to completely remove the solvent and obtain the electrode.

[0056] The above-mentioned electrodes are used as anode electrodes and assembled with cathode electrodes to obtain membrane electrodes.

[0057] In this embodiment, the platinum loading of the cathode electrode is approximately 0.3 mg Pt / cm². 2 The ionomer to carbon weight ratio (I / C) is 0.75, where I represents Nafion resin. The electrode loading is determined by weighing before and after catalyst layer transfer.

[0058] In this embodiment, a 12 μm proton exchange membrane (Gore) can be thermo-pressed between two electrode patches (anode and cathode) and heated at 135°C for 5 minutes, applying 0.3 kN / cm. 2 The force of the active area, assembled with 50 cm 2 A membrane electrode with a mass active area. The aforementioned pre-prepared carrier coated with the mixed slurry can be used as an anode electrode patch to assemble the membrane electrode.

[0059] In this application embodiment, electrochemical tests were also performed on Example 1 and Comparative Example 1, respectively. The electrochemical measurements were performed using a 3-coil single-cell fixture equipped with a 50 square centimeter mass active area graphite flow field. The applied torque during battery assembly was 8 Nm, the compression of the gas diffusion medium was set to 20%, and an incompressible reinforced pad of appropriate thickness was used. Fuel cell testing was conducted on a 100 W test bench. The membrane electrode assembly (MEA) test conditions were: temperature 80°C, anode / cathode humidity 100%, anode / cathode pressure 100 kPa / 90 kPa, and anode / cathode metering ratio of 1.5 / 2.

[0060] In the embodiments of this application, Figure 4 This is a polarization curve of a membrane electrode containing a resin-titanium oxide composite before and after reverse polarization. Figure 5 The graphs show the polarization curves of a membrane electrode containing an anti-reverse catalyst, iridium oxide, before and after reverse polarization. Compared to adding a traditional anti-reverse catalyst to the anode, the membrane electrode incorporating a resin-titanium oxide composite exhibits a polarization rate of 3000 mA / cm² before reverse polarization. 2 The performance at the current density improved by 36 mV, and it can be seen that the addition of the anti-reverse catalyst has a significant impact on the performance of the membrane electrode, especially after 45 min of reverse electrode reaction. Due to the voltage rise to 1.5 V or even higher during the reverse electrode reaction, under such harsh conditions, the addition of the Nafion resin-titanium oxide catalyst layer resulted in a performance improvement of 3000 mA / cm² after reverse electrode reaction. 2At current density, the performance only decreased by 2%, while the catalyst layer with added anti-reverse electrode catalyst experienced a 7.7% performance decrease after reversal. When faced with carbon corrosion, the traditional anode suffers severe structural collapse after carbon corrosion, while the structure of the Nafion resin-titanium oxide anode is less affected. By constructing a stable perfluorosulfonic acid resin and porous network, the impact of catalyst degradation and structural changes on performance is reduced, allowing for smoother proton and gas transport and improving the overall efficiency of the battery.

[0061] As can be seen from the embodiments provided in this application above, titanium oxide is dispersed in isopropanol to obtain a first mixed solution; the first mixed solution is mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution is vacuum dried to obtain a Nafion resin-titanium oxide composite; the Nafion resin-titanium oxide composite and platinum-carbon catalyst are placed in a ball mill jar according to a preset ratio for ball milling to obtain a mixed slurry; the mixed slurry is coated onto a preset support to form an anti-reverse electrode catalytic layer on the preset support to obtain an anti-reverse electrode. This application, by introducing a Nafion resin-titanium oxide composite, can retain the highly active Pt / C catalyst and construct a sustainable proton conduction network and physical structural support independent of the carbon support. The rigid Nafion resin-titanium oxide composite particles are distributed between the Pt / C particles, which can prevent the complete collapse of the pores after carbon corrosion and maintain the gas transport path. By controlling the pH value of the titanium metal oxide solution and then mixing it with the Nafion resin solution, followed by stirring and standing, the titanium metal oxide particles and Nafion resin can be more tightly bonded to form a more stable structure. Ball milling can achieve more uniform mixing of the Nafion resin-titanium oxide composite powder and the platinum-carbon catalyst. A uniformly dispersed slurry is obtained, and then coated onto the surface of a pre-set carrier by a scraping method to form an anode catalyst layer. The Nafion resin in the anode catalyst layer is independent of the carbon carrier, which can avoid the migration and aggregation of traditional resins after carbon corrosion, thereby constructing a stable proton transport network. In this anode catalyst layer, titanium oxide particles can form a "scaffold" between Pt / C nanoparticles, and even if carbon corrosion occurs, the porous network can still be preserved, ensuring the proton and gas transport channels, maintaining the integrity of the porous structure, and improving the working efficiency of the battery. In addition, the preparation method is simple, only requiring the Nafion resin-titanium oxide composite in the anode slurry, without the need to develop new carriers, making it easy to promote industrialization.

[0062] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of making an anti-polar electrode, characterized by, The method includes: Titanium oxide was dispersed in isopropanol to obtain the first mixed solution; The first mixed solution was mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution was vacuum dried to obtain Nafion resin-titanium oxide composite. The Nafion resin-titanium oxide composite and platinum-carbon catalyst were placed in a ball mill jar and ball milled in a preset ratio to obtain a mixed slurry. The mixed slurry is coated onto a preset carrier to form an anti-reverse electrode catalytic layer, thereby obtaining the anti-reverse electrode.

2. The method according to claim 1, characterized in that, The titanium oxide includes one or more of titanium monoxide, titanium dioxide, and titanium trioxide; The particle size of the titanium oxide is 10 nm-35 nm; The pH value of the first mixed solution is 2-3.

3. The method according to claim 2, characterized in that, The concentration of the Nafion resin solution is 20%; The solid content of the mixed slurry is 18%-22%; The preset ratio is 0.5-1.5, which represents the mass ratio of Nafion resin in the Nafion resin-titanium oxide composite to the carbon support in the platinum-carbon catalyst.

4. The method according to claim 1, characterized in that, The step of coating the mixed slurry onto a predetermined carrier to form an anti-reverse electrode on the predetermined carrier includes: The mixed slurry is scraped onto the preset carrier at a preset scraping rate to obtain an initial scraped sample; The initial coated sample is left to stand at a preset temperature, and then dried to obtain the anti-reverse electrode.

5. The method according to claim 1, characterized in that, The preset scraping rate is 10 mm / s-15 mm / s; The thickness of the mixed slurry coated on the preset carrier is 80 μm-120 μm; The preset temperature is 40℃-48℃; The drying process is carried out at a temperature of 75℃-85℃.

6. The method according to claim 1, characterized in that, The first mixed solution is mixed with Nafion resin solution to obtain a second mixed solution, and the second mixed solution is vacuum dried to obtain a resin-titanium oxide composite, comprising: The first mixed solution is mixed with the Nafion resin solution and stirred at room temperature to obtain a stirred solution; The stirred solution was allowed to stand at room temperature until the second mixed solution was obtained. The second mixed solution was subjected to vacuum drying to obtain the resin-titanium oxide composite.

7. The method according to claim 6, characterized in that, The stirring time is 10 min-15 min, and the settling time is 6 h-20 h; The vacuum drying temperature is 50℃-150℃.

8. The method according to claim 1, characterized in that, The step of placing the Nafion resin-titanium oxide composite and platinum-carbon catalyst in a ball mill jar at a preset ratio for ball milling to obtain a mixed slurry includes: The Nafion resin-titanium oxide composite and the platinum-carbon catalyst were placed in the ball mill jar according to the preset ratio, and ethanol, n-propanol and deionized water were added for ball milling to obtain the mixed slurry. The ball milling process takes 5-12 hours and the ball milling speed is 300-900 rpm. The ratio of ethanol, n-propanol and deionized water is 1:1:

2.

9. A reverse polarity resistant electrode, characterized in that, The anti-reverse electrode is prepared using the method described in any one of claims 1-8.

10. A membrane electrode, characterized in that, The membrane electrode includes the anti-reverse electrode as described in claim 9.

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