Anode catalyst layer, preparation method thereof and membrane electrode

Abstract

The invention discloses an anode catalyst layer, a preparation method thereof and a membrane electrode, and relates to the technical field of proton exchange membrane water electrolysis, the anode catalyst layer is of a single-layer structure and is prepared by drying anode catalyst slurry, and the anode catalyst slurry comprises the following components in parts by weight: 0.05-10 parts of a high-molecular compound; 0.5 to 10 parts of an iridium catalyst; 0.5 to 12 parts of perfluorinated sulfonic acid resin; 5 to 120 parts of a solvent; wherein the high-molecular compound is used for forming a reinforced structure in the anode catalyst layer, and the high-molecular compound comprises at least one of carboxymethyl cellulose sodium, polyvinylidene fluoride, polyacrylic acid, polyimide or butadiene styrene rubber; and the mass of the high-molecular compound is 20%-100% of the mass of the anode catalyst. By introducing the high-molecular compound, the mechanical property and the electrochemical property of the membrane electrode can be improved.

Description

Technical Field

[0001] This application relates to the field of proton exchange membrane water electrolysis technology, specifically to an anode catalyst layer and its preparation method and membrane electrode. Background Technology

[0002] In the field of proton exchange membrane water electrolysis (PEMWE) technology, the membrane electrode assembly (MEA) is a core component, and its performance directly determines the operating efficiency and stability of the entire system. A membrane electrode typically consists of a proton exchange membrane, two catalytic layers on either side, and a gas diffusion layer. The anode catalyst layer (ACL) is the core functional layer where the anodic oxidation reaction occurs, and its structural stability and catalytic activity directly determine the overall electrochemical performance of the membrane electrode.

[0003] Currently, conventional anode catalyst layers lack effective structural reinforcement mechanisms, resulting in insufficient mechanical strength. In electrode fabrication and system operation scenarios, even minor impacts or compression can cause deformation and cracking of the anode catalyst layer. Damage to the catalyst layer directly undermines the structural integrity of the membrane electrode assembly (MEA), affecting its core functions of conductivity and mass transfer. Furthermore, differential pressure operation is a typical condition for PEMWE systems. Insufficient structural strength will make it difficult to withstand the continuous stress generated by differential pressure, gradually exacerbating internal structural damage to the MEA. This may lead to interfacial separation between the catalyst layer and the proton exchange membrane, or even through-cracks in the catalyst layer itself, further accelerating performance degradation and shortening lifespan. In addition, there is still significant room for improvement in the electrochemical performance of the MEA. These issues collectively constrain the further development and application of PEMWE technology. Summary of the Invention

[0004] The purpose of this application is to provide an anode catalyst layer, a method for preparing the same, and a membrane electrode, so as to improve the mechanical and electrochemical properties of the membrane electrode.

[0005] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides an anode catalyst layer, which is prepared by drying an anode catalyst slurry. The anode catalyst slurry comprises the following components by weight: 0.05 to 10 parts of a polymer compound; 0.5 to 10 parts of an iridium catalyst; 0.5 to 12 parts of a perfluorosulfonic acid resin; and 5 to 120 parts of a solvent.

[0006] Typically, anode catalyst slurry mainly consists of an anode catalyst, perfluorosulfonic acid resin, and a solvent. The solvent dissolves the perfluorosulfonic acid resin, providing a good medium for the subsequent dispersion of the anode catalyst. Ball milling is used to uniformly disperse the anode catalyst in the perfluorosulfonic acid resin solution. After drying to remove the solvent, the resulting anode catalyst layer exhibits a structure where the anode catalyst is encapsulated by the perfluorosulfonic acid resin. However, when this type of anode catalyst layer is applied to membrane electrodes, it suffers from insufficient mechanical strength.

[0007] This application involves adding a polymer compound to the anode catalyst slurry. After drying to form the anode catalyst layer, the polymer compound forms a reinforcing structure on the outside of the perfluorosulfonic acid resin. This reinforcing structure not only significantly increases the mechanical strength of the membrane electrode, thereby effectively enhancing its pressure resistance, but also improves the structural stability of the catalyst layer, mitigating structural degradation during operation and extending its service life. This anode catalyst layer with a reinforced structure effectively solves the problems of insufficient mechanical strength and easy breakage of the membrane electrode under differential pressure operation. Simultaneously, this reinforcing structure also supports the framework of the anode catalyst layer, promoting a more porous structure that exposes more catalyst active sites, thereby enhancing catalytic activity and optimizing the electrochemical performance of the membrane electrode.

[0008] In-depth research has revealed that when the molecular structure of a polymer compound contains polar groups or is an elastomer, it helps to further improve the mechanical and electrochemical properties of the membrane electrode. Preferably, the polymer compound includes at least one of sodium carboxymethyl cellulose (CMC-Na), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), polyimide (PI), or styrene-butadiene rubber (SBR).

[0009] Specifically, when the molecular structure of a polymer contains polar groups (such as -CF2- of PVDF, -OH / -COONa of CMC-Na, and the imide ring of PI), hydrogen bonds, dipole interactions, or rigid frameworks are easily formed between the chains, which can construct a dense and tough "three-dimensional support network" in the catalyst layer. This network can effectively disperse external forces (such as coating extrusion, vibration and impact) and reduce the deformation and breakage of the catalyst layer. At the same time, these polar groups can also form interfacial forces with the proton exchange membrane (such as -SO3H of Nafion membrane) and the surface of catalyst layer particles (such as IrO2 catalyst) (such as -OH of CMC-Na forming hydrogen bonds with -SO3H of the membrane, and -CF2- of PVDF forming dipole adsorption with the polar surface of the catalyst particles), which significantly improves the adhesion strength between the catalyst layer and the membrane and gas diffusion layer, and avoids interfacial separation under differential pressure conditions.

[0010] These polar groups can form moderately strong interactions with catalyst particles. This interaction effectively inhibits particle aggregation and ensures continuous exposure of catalytic active sites by adsorbing and immobilizing the catalyst particles; however, it avoids covering the active sites due to excessive adsorption, thus preventing inhibition of the catalytic reaction. For example, the -COOH group of PAA interacts with the IrO2 surface... 4+ By forming weak coordination bonds, the catalyst can be stabilized without hindering the reaction site.

[0011] In addition, PVDF and PI have excellent acid and oxidation resistance, making them suitable for the harsh environment of high potential and strong acidity of PEMWE anodes. Their molecular structure is not easily degraded during long-term use, which can stably maintain the mechanical support of the catalyst layer. Elastomers such as SBR can further enhance the catalyst layer's resistance to breakage by buffering external impacts through "elastic deformation".

[0012] The amount of polymer compound added also affects the mechanical and electrochemical properties of the membrane electrode. Increasing the amount of polymer compound added has a positive effect on improving the mechanical properties of the membrane electrode; however, excessive addition can lead to a series of adverse effects, at least in the following aspects: First, excessive polymer compound can significantly increase the particle size of the catalyst slurry, making the subsequently coated catalyst layer more prone to light transmission and reducing the uniformity of the catalyst layer structure; Second, as the amount of polymer compound added increases, the slurry coating thickness will also increase, not only prolonging the drying process time but also making it difficult to control the catalyst loading within a uniform range during coating due to the fluidity of the slurry itself; these problems of insufficient structural uniformity and loading fluctuation will ultimately have a negative impact on the electrochemical performance of the membrane electrode.

[0013] As a preferred embodiment, the mass of the polymeric compound is 5% to 100% of the mass of the iridium catalyst. More preferably, the mass of the polymeric compound is 20% to 100% of the mass of the iridium catalyst; even more preferably, the mass of the polymeric compound is 20% of the mass of the iridium catalyst.

[0014] As a preferred embodiment, the anode catalyst slurry comprises the following components by weight: 0.05 to 5 parts of polymer compound; 0.5 to 5 parts of iridium catalyst; 0.5 to 5 parts of perfluorosulfonic acid resin; and 5 to 100 parts of solvent.

[0015] As a preferred embodiment, the anode catalyst slurry comprises the following components by weight: 0.05 to 1 part of polymer compound; 0.6 to 1 part of iridium catalyst; 0.6 to 1.2 parts of perfluorosulfonic acid resin; and 5 to 60 parts of solvent.

[0016] As a preferred embodiment, the number-average molecular weight of the polymer compound is 5000 g / mol to 1000000 g / mol.

[0017] As a preferred embodiment, the iridium catalyst includes IrO2 and IrRuO2. x1 IrO2 / TiO2, IrO2 / NbO x1 IrO2 / Ta2O5, IrO2 / WO x1 or IrO2 / Nb2O 5-x2 At least one of them, where x1 is 1 to 2 and x2 is 0 to 3.

[0018] As a preferred embodiment, the perfluorosulfonic acid resin includes at least one of Nafion D2020, Nafion NR50, IC100, or Aquivion D79-25B.

[0019] As a preferred embodiment, the solvent includes a first solvent for dissolving the polymer compound and a second solvent for dissolving the perfluorosulfonic acid resin.

[0020] Preferably, the first solvent and the second solvent are the same or different, and include at least one of isopropanol, ethylene glycol, ethanol, n-propanol, and water. As an example, the polymer is a water-soluble polymer, the first solvent includes water, and the second solvent includes isopropanol.

[0021] As a preferred embodiment, the method for preparing the anode catalyst slurry includes: uniformly mixing a polymer compound, an iridium catalyst, a perfluorosulfonic acid resin, and a solvent.

[0022] As a preferred embodiment, the method for uniformly mixing the polymer compound, iridium catalyst, perfluorosulfonic acid resin, and solvent includes the following steps: A1: Dissolve the polymer compound in the first solvent to obtain the first solution; A2: Mix a portion of the first solution with the iridium catalyst, and perform a first ball milling and wetting process to obtain the second solution; A3: Add perfluorosulfonic acid resin to the second solution, and perform a second ball milling and mixing to obtain the third solution; A4: Add the remaining mixture of the first solution and the second solvent to the third solution and mix thoroughly.

[0023] Step A2 above is used to initially wet the iridium catalyst. Preferably, in step A2, the initial ball milling wettation is performed at a rotation speed of 500 rpm to 1500 rpm for 5 to 15 minutes. More preferably, the rotation speed is 750 rpm to 1200 rpm for 6 to 12 minutes. As an example, the rotation speed is 1000 rpm for 10 minutes.

[0024] As a preferred embodiment, 2mm to 5mm grinding balls are used in step A2. More preferably, 2mm grinding balls, 3mm grinding balls, and 5mm grinding balls are used in a mass ratio of 1:1:1.

[0025] As a preferred embodiment, in step A3, the rotation speed during the second ball milling is 500 rpm to 1000 rpm, and the time is 30 minutes to 100 minutes.

[0026] Preferably, in step A3, during the second ball milling, the ball is first milled at 500 rpm to 1000 rpm for 2 to 10 minutes, then stopped for 2 to 5 minutes, and then milled again at 500 rpm to 1000 rpm for 2 to 10 minutes, repeating this process multiple times. As an example, the ball is first milled at 750 rpm for 5 minutes, then stopped for 2 minutes, and then milled again at 750 rpm for 5 minutes, repeating this process 4 times.

[0027] As a preferred embodiment, 2mm to 5mm grinding balls are used in step A3. More preferably, 2mm grinding balls, 3mm grinding balls, and 5mm grinding balls are used in a mass ratio of 1:1:1.

[0028] As a preferred embodiment, the method for uniformly mixing the polymer compound, iridium catalyst, perfluorosulfonic acid resin, and solvent includes the following steps: B1: The polymer compound, iridium catalyst and part of the first solvent are mixed using the first ball milling process to obtain the first mixture; B2: The first mixture is mixed with perfluorosulfonic acid resin using a second ball milling process to obtain a second mixture; B3: The second mixture, the second solvent, and the remaining first solvent are mixed evenly using a third ball milling process.

[0029] As a preferred embodiment, in step B1, the rotational speed of the first ball milling process is 500 rpm to 1000 rpm, and the time is 5 minutes to 12 minutes. More preferably, the rotational speed is 650 rpm to 750 rpm, and the time is 5 minutes to 10 minutes. As an example, the rotational speed is 650 rpm, and the time is 10 minutes.

[0030] As a preferred embodiment, in step B1, 2mm to 5mm grinding balls are used. More preferably, 2mm grinding balls, 3mm grinding balls, and 5mm grinding balls are used in a mass ratio of 2:1:2.

[0031] As a preferred embodiment, in step B2, the second ball milling process involves a rotation speed of 500 rpm to 1000 rpm and a time of 50 minutes to 90 minutes. More preferably, the rotation speed is 650 rpm to 750 rpm and the time is 50 minutes to 60 minutes. As an example, the rotation speed is 650 rpm and the time is 60 minutes.

[0032] As a preferred embodiment, in step B2, 2mm to 5mm grinding balls are used. More preferably, 2mm grinding balls, 3mm grinding balls, and 5mm grinding balls are used in a mass ratio of 2:1:2.

[0033] As a preferred embodiment, in step B3, the third ball milling process involves a rotation speed of 500 rpm to 1000 rpm and a time of 50 minutes to 90 minutes. More preferably, the rotation speed is 650 rpm to 750 rpm and the time is 50 minutes to 60 minutes. As an example, the rotation speed is 650 rpm and the time is 60 minutes.

[0034] As a preferred embodiment, in step B3, 2mm to 5mm grinding balls are used. More preferably, 2mm grinding balls, 3mm grinding balls, and 5mm grinding balls are used in a mass ratio of 2:1:2.

[0035] As a preferred embodiment, the iridium catalyst loading in the anode catalyst layer is 0.9 mg / cm³. 2 ~1.1mg / cm 2 As an example, the iridium catalyst is IrO2.

[0036] In a second aspect, this application provides a method for preparing the aforementioned anode catalyst layer, comprising: coating the anode catalyst slurry onto the surface of a substrate by spraying or scraping, and drying to obtain the anode catalyst layer. The choice between spraying or scraping depends on the viscosity of the anode catalyst slurry; low-viscosity slurries are suitable for spraying, while high-viscosity slurries are suitable for scraping.

[0037] As a preferred option, the drying temperature is 70℃~90℃.

[0038] In a third aspect, this application provides a membrane electrode comprising the aforementioned anode catalyst layer.

[0039] Compared with the prior art, the technical solution of this application has the following beneficial effects: This application introduces a polymer compound with a specific structure into the anode catalyst slurry and controls its mass ratio with the iridium catalyst. After drying, a stable reinforcing structure can be constructed on the outside of the perfluorosulfonic acid resin. This reinforcing structure can improve the mechanical strength of the membrane electrode, effectively enhance its pressure resistance, improve the structural degradation of the membrane electrode during operation, and also improve the electrochemical performance of the membrane electrode. Attached Figure Description

[0040] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein: Figure 1 Single-cell galvanic durability test curves of the membrane electrodes prepared in Example 1 and Comparative Example 1 of this application; Figure 2 The single-cell galvanic durability test curves of the membrane electrodes prepared in Examples 2-4 and Comparative Example 2 of this application are shown. Figure 3 The constant current durability test curves of the membrane electrodes prepared in Example 1 and Comparative Example 1 of this application under the operating conditions of differential pressure between anode and cathode are shown. Figure 4 This is a surface morphology image of the membrane electrode prepared in Example 1 of this application after differential pressure testing; Figure 5 The image shows the surface morphology of the membrane electrode prepared in Comparative Example 1 of this application after differential pressure testing. Detailed Implementation

[0041] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown.

[0042] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Unless otherwise specified, the reagents and raw materials used can be purchased commercially. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or according to the product instructions.

[0043] Sodium carboxymethyl cellulose powder (CMC-Na) was purchased from Sinopharm Group, grade CP 800-1200 (Shanghai Testing); iridium oxide granules (IrO2) were purchased from Heraeus, grade H2EL-IrO; Nafion D2020 was purchased from Chemours; IC100 was purchased from Asahi Glass (AGC); isopropanol was purchased from Sinopharm Group; proton exchange membrane was purchased from Chemours, grade Nafion NR212; thin fiber cloth was purchased from Shanghai Suopin Aerospace Materials Technology Co., Ltd., specification PC3N; cathode catalyst layer was 4001 cathode catalyst layer from Shanghai Shengshui New Energy Technology Co., Ltd.; single cell test PTL was purchased from Beijing Maianrui Technology Co., Ltd., grade MOTT. 0.25mm, single-cell test GDL was purchased from Shanghai Hesen Electric Co., Ltd., brand name is Toray 39BB; ball milling equipment is Simada TMV-200T or YXQM Miqi planetary ball mill; spraying equipment is Suzhou Xifeng XF900-5T; scraping equipment is MS-ZN320B wire rod coating machine.

[0044] Example 1 (1) Preparation of anode catalyst slurry This embodiment provides an anode catalyst slurry, comprising the following components by weight: 0.12 parts CMC-Na, 0.6 parts IrO2, 0.6 parts Nafion D2020, 15 parts water, and 44.7 parts isopropanol; its preparation method is as follows: 1) Dissolve 0.12g of CMC-Na powder in 15g of water and name it solution A.

[0045] 2) Place 1.2g of solution A, 0.6g of IrO2, 9g of 2mm milling beads, 9g of 3mm milling beads, and 9g of 5mm milling beads into a milling jar (Smida TMV-200T) and mill at 1000rpm for 10 minutes to initially wet the IrO2.

[0046] 3) Add 0.6g Nafion D2020 to the ball mill jar and ball mill to mix. First, ball mill at 750rpm for 5 minutes, then stop rotating for 2 minutes, and then ball mill at 750rpm for 5 minutes. Repeat this process 4 times.

[0047] 4) Add the remaining solution A and the mixed solution of 44.7g isopropanol into the ball mill jar, transfer the catalyst system to the container, and subject the container to cold water ultrasonic treatment for 30 minutes to obtain the anode catalyst slurry.

[0048] (2) Preparation of the anode catalyst layer The anode catalyst slurry prepared in this embodiment was coated onto the surface of a thin fiber cloth by fine ultrasonic spraying. X-ray fluorescence spectroscopy (XRF) showed that the IrO2 loading was 0.9 mg / cm³.2 ~1.1mg / cm 2 The slurry was dried at 90°C to obtain the anode catalyst layer.

[0049] (3) Fabrication of membrane electrodes The anodic and cathode catalytic layers were transferred onto the two opposing surfaces of the proton exchange membrane using a hot-press transfer method to obtain the membrane electrode PEM-1. The hot plate temperature during the hot-press transfer process was 180℃, the pressure was 3MPa, and the duration was 20 minutes.

[0050] Example 2 (1) Preparation of anode catalyst slurry This embodiment provides an anode catalyst slurry, comprising the following components by weight: 0.2 parts CMC-Na, 1 part IrO2, 1.2 parts IC100, 2 parts water, and 4.3 parts isopropanol. Its preparation method is as follows: 1) Place 0.2g CMC-Na powder, 1g IrO2, 10g 2mm grinding beads, 5g 3mm grinding beads, 10g 5mm grinding beads, and 1g water into a grinding jar (YXQM planetary ball mill) and grind at 650rpm for 10 minutes.

[0051] 2) Add 1.2g of IC100 to the ball mill jar and ball mill at 650rpm for 60 minutes.

[0052] 3) Add 1g of water and 4.3g of isopropanol to the ball mill jar, and continue ball milling at 650rpm for 60 minutes to obtain the anode catalyst slurry.

[0053] (2) Preparation of the anode catalyst layer The anode catalyst slurry prepared in this embodiment was coated onto the surface of a thin fiber cloth using a flatbed coating method. X-ray fluorescence spectroscopy (XRF) showed that the IrO2 loading was 0.9 mg / cm³. 2 ~1.1mg / cm 2 The slurry was dried at 70°C to obtain the anode catalyst layer.

[0054] (3) Fabrication of membrane electrodes Using the same hot-press transfer method as in Example 1, the anode catalyst layer and the cathode catalyst layer were transferred onto the two opposite surfaces of the proton exchange membrane to obtain the membrane electrode PEM-2.

[0055] Example 3 This embodiment provides an anode catalyst slurry, which differs from Example 2 only in that the amount of CMC-Na added is 1 part, which is 100% of the weight of IrO2. The specific composition is shown in Table 1.

[0056] Following the method of Example 2, the anode catalyst slurry, the anode catalyst layer, and the membrane electrode PEM-5 were prepared sequentially.

[0057] Example 4 This embodiment provides an anode catalyst slurry, which differs from Example 2 only in that the amount of CMC-Na added is 0.05 parts, which is 5% of the weight of IrO2. The specific composition is shown in Table 1.

[0058] Following the method of Example 2, the anode catalyst slurry, the anode catalyst layer, and the membrane electrode PEM-6 were prepared sequentially.

[0059] Comparative Example 1 This comparative example provides an anode catalyst slurry, which differs from Example 1 only in that it does not contain CMC-Na. The specific composition is shown in Table 1.

[0060] Following the method described in Example 1, the anode catalyst slurry, the anode catalyst layer, and the membrane electrode PEM-3 were prepared sequentially.

[0061] Comparative Example 2 This comparative example provides an anode catalyst slurry, which differs from Example 2 only in that it does not contain CMC-Na. The specific composition is shown in Table 1.

[0062] Following the method of Example 2, the anode catalyst slurry, the anode catalyst layer, and the membrane electrode PEM-4 were prepared sequentially.

[0063] Table 1 Component ratio and coating method

[0064] Mechanical performance testing The membrane electrode was fabricated into a strip sample with a length of 10 cm and a width of 1 cm. Its elongation at break was tested using a computer-controlled servo tensile testing machine (Dongguan Haida Instruments, HD-B609-S). For each membrane electrode, three sets of tests were performed in parallel, and the average value of the obtained data was calculated. The test results are shown in Table 2.

[0065] The comparison results between Example 1 and Comparative Example 1 show that the tensile strength of the membrane electrode prepared by adding CMC-Na to the anode catalyst layer is significantly improved; this conclusion is also verified by the comparison results between Examples 2-4 and Comparative Example 2. Therefore, this application can effectively improve the mechanical strength of the membrane electrode by introducing CMC-Na with polar groups into the anode catalyst layer.

[0066] Further analysis of the intra-group comparison results of Examples 2-4 shows that as the basis weight ratio of CMC-Na relative to the catalyst increases from 5% to 100%, the tensile breaking strength of the membrane electrode gradually increases. When the basis weight ratio of CMC-Na relative to the catalyst is 100%, the maximum force reaches 21.104 N, and the tensile strength reaches 40.584 MPa.

[0067] Table 2 Mechanical Performance Test Results

[0068] Electrochemical performance testing A gas diffusion layer was assembled on the membrane electrode, and the membrane electrode was subjected to single-cell constant current durability testing on the Ruineng battery testing system. The test temperature was set at 60℃ and the current density at 3.5A / cm². 2 The test results are as follows Figures 1 to 3 As shown.

[0069] Combine Figures 1 to 3 It can be seen that, regardless of whether spraying or blade coating is used, the initial voltage of membrane electrodes (PEM-1, PEM-2, PEM-5, and PEM-6) prepared with CMC-Na is significantly lower than that of membrane electrodes (PEM-3 and PEM-4) without CMC-Na. This indicates that introducing CMC-Na with polar groups can effectively improve the electrochemical performance of membrane electrodes. The reason for this may be that CMC-Na constructs a reinforcing structure supporting the anolyte in the anode catalyst, promoting a more porous microstructure in the anode catalyst layer, thereby exposing more catalyst active sites, thus enhancing catalytic activity and optimizing the electrochemical performance of the membrane electrode. Simultaneously, the interaction strength between the polar groups in CMC-Na and IrO2 is moderate. It can both adsorb and fix IrO2 particles, preventing their aggregation and ensuring continuous exposure of active sites, and avoids covering the active sites due to excessive adsorption, thus preventing inhibition of the catalytic reaction. The lower voltage in the early stage of PEM-5 is due to the catalyst layer being in the activation process, while the voltage rise in the later stage is due to the relatively large amount of CMC-Na added, which causes the anode catalyst layer to decay, but still meets the application requirements.

[0070] Figure 3 The results show the constant current durability test under differential pressure operation (anode pressure 0.3 MPa, cathode pressure 3.3 MPa). Compared with PEM-3 prepared without CMC-Na, the voltage of PEM-1 is significantly reduced, which further confirms that CMC-Na can effectively improve the electrochemical performance of the membrane electrode under differential pressure operation.

[0071] The following steps were taken to observe the membrane electrode after differential pressure testing using the Quantum SEM2100 from Guoyi Quantum: First, cut the area to be observed with a sharp blade and place it on the sample stage provided with the SEM (conductive tape was pre-attached to the surface of the sample stage to fix the membrane electrode); then, place the sample stage into the SEM chamber, and after the chamber was evacuated, adjust the height of the sample stage and turn on the electron beam to observe the sample morphology. If the sample morphology is blurry during observation, adjusting the focusing parameters and astigmatism correction parameters can improve the imaging effect.

[0072] Figure 4 This is a surface morphology image of PEM-1 after differential pressure testing. Figure 5 The image shows the surface morphology of PEM-3 after differential pressure testing. Figure 5 In the PEM-3 anode catalyst layer, obvious cutting marks were observed, with a thinning rate of (48.49μm-42.17μm) / 48.49μm×100%=13% at the cutting marks. Figure 4 In the PEM-1 anode catalyst layer, there are no obvious cutting marks. This indicates that by introducing CMC-Na into the anode catalyst layer, this application can significantly improve the structural stability of the catalyst layer and mitigate structural degradation during operation.

[0073] It should be noted that, based on the methods described in the above embodiments, similar methods can be used to replace the polymer compound with other types, such as polyvinylidene fluoride, polyacrylic acid, polyimide, or styrene-butadiene rubber, to prepare the corresponding anode catalyst slurry, anode catalyst layer, and membrane electrode. Membrane electrodes prepared by such substitution schemes can also achieve improvements in mechanical and electrochemical performance; therefore, the relevant embodiments will not be described in detail in this invention.

[0074] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. An anode catalyst layer, characterized in that, It has a single-layer structure and is prepared by drying an anode catalyst slurry; the anode catalyst slurry comprises the following components by weight: 0.05 to 10 parts of polymeric compound; Iridium catalyst 0.5 to 10 parts; 0.5 to 12 parts of perfluorosulfonic acid resin; Solvent: 5 to 120 parts; The polymeric compound is used to form a reinforcing structure in the anode catalyst layer, and the polymeric compound includes at least one of sodium hydroxymethyl cellulose, polyvinylidene fluoride, polyacrylic acid, polyimide, or styrene-butadiene rubber; and the mass of the polymeric compound is 20% to 100% of the mass of the iridium catalyst.

2. The anode catalyst layer according to claim 1, characterized in that, The anode catalyst slurry comprises the following components in parts by weight: 0.05 to 1 part of polymeric compound; Iridium catalyst 0.6 to 1 part; 0.6 to 1.2 parts of perfluorosulfonic acid resin; Solvent: 5 to 60 parts.

3. The anode catalyst layer according to claim 1 or 2, characterized in that, The number average molecular weight of the polymer compound is 5000 g / mol to 1000000 g / mol; and / or, the mass of the polymer compound is 20% of the mass of the iridium catalyst.

4. The anode catalyst layer according to claim 1 or 2, characterized in that, The iridium catalyst includes IrO2 and IrRuO2. x1 IrO2 / TiO2, IrO2 / NbO x1 IrO2 / Ta2O5, IrO2 / WO x1 or IrO2 / Nb2O 5-x2 At least one of them, wherein x1 is 1 to 2 and x2 is 0 to 3; And / or, the perfluorosulfonic acid resin includes at least one of Nafion D2020, Nafion NR50, IC100 or Aquivion D79-25B; And / or, the solvent includes a first solvent for dissolving the polymer compound and a second solvent for dissolving the perfluorosulfonic acid resin; the first solvent and the second solvent may be the same or different, and include at least one of isopropanol, ethylene glycol, ethanol, n-propanol and water.

5. The anode catalyst layer according to claim 1, characterized in that, The preparation method of the anode catalyst slurry includes: mixing a polymer compound, an iridium catalyst, a perfluorosulfonic acid resin and a solvent evenly.

6. The anode catalyst layer according to claim 5, characterized in that, Methods for uniformly mixing polymer compounds, iridium catalysts, perfluorosulfonic acid resins, and solvents include: A polymer compound is dissolved in a first solvent to prepare a first solution; A portion of the first solution was mixed with an iridium catalyst and subjected to a first ball milling and wetting process to obtain a second solution. Add perfluorosulfonic acid resin to the second solution, and perform a second ball milling to mix, to obtain the third solution; Add the remaining mixture of the first solution and the second solvent to the third solution and mix thoroughly. Alternatively, methods for uniformly mixing the polymer compound, iridium catalyst, perfluorosulfonic acid resin, and solvent include: The polymer compound, iridium catalyst, and part of the first solvent are mixed using a first ball milling process to obtain a first mixture. The first mixture is mixed with perfluorosulfonic acid resin using a second ball milling process to obtain a second mixture; The second mixture, the remaining first solvent, and the second solvent are mixed evenly using a third ball milling process.

7. The anode catalyst layer according to claim 6, characterized in that, The rotation speed during the first ball mill wetting process is 500 rpm to 1500 rpm, and the time is 5 minutes to 15 minutes. And / or, the rotation speed during the second ball milling is 500 rpm to 1000 rpm, and the time is 30 minutes to 100 minutes; And / or, the first ball milling wetting and the second ball milling mixing use 2mm~5mm ball milling beads.

8. The anode catalyst layer according to claim 6, characterized in that, The first ball milling process has a rotation speed of 500 rpm to 1000 rpm and a time of 5 minutes to 12 minutes; And / or, the second ball milling process has a rotation speed of 500 rpm to 1000 rpm and a time of 50 minutes to 90 minutes; And / or, the third ball milling process has a rotation speed of 500 rpm to 1000 rpm and a time of 50 minutes to 90 minutes; And / or, the first ball milling process, the second ball milling process and the third ball milling process all use 2mm~5mm grinding balls.

9. A method for preparing an anode catalyst layer as described in any one of claims 1 to 8, characterized in that, include: The anode catalyst slurry is coated onto the surface of the substrate by spraying or scraping, and then dried to obtain the anode catalyst layer.

10. A membrane electrode, characterized in that, Includes the anode catalyst layer as described in any one of claims 1 to 8.

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