A high-precision catalyst layer mass transfer channel construction method

Abstract

The application belongs to the field of fuel cells, and particularly relates to a high-precision catalytic layer mass transfer channel construction method. The method comprises the following steps: configuring inks, including: mixing catalyst inks A according to a solvent: catalyst mass ratio of (0-1):(0-1); mixing ionomer inks B according to a solvent: ionomer mass ratio of (0-1):(0-1); and mixing functional inks C according to a solvent: additive mass ratio of (0-1):(0-1); in step 2, using an inkjet printing device, any two of the catalyst inks A, the ionomer inks B or the functional inks C are printed in different regions of the same catalytic layer forming plane at intervals, and multiple composite layers are stacked, wherein at least one composite layer is printed by the catalyst inks A and the ionomer inks B. The method avoids the phenomenon that the catalyst is poisoned by the ionomer, and ensures that a macroscopic three-phase reaction interface is constructed on the catalytic layer to form a mass transfer channel, thereby optimizing the structure of the catalytic layer.

Description

Technical Field

[0001] This invention belongs to the field of fuel cells, specifically relating to a method for constructing high-precision catalyst layer mass transfer channels. Background Technology

[0002] Fuel cells possess environmental friendliness, high energy conversion efficiency, and rapid low-temperature start-up capabilities, making them promising candidates for applications in transportation, portable power sources, and aerospace. However, to commercialize proton exchange membrane fuel cells (PEMFCs), it is crucial to reduce the extensive use of precious metal Pt catalysts, thereby lowering the high cost of membrane electrode assembly (MEA) fabrication. Ionomers are a vital component of the PEMFC, serving not only as an ion exchange membrane transferring protons and water from the anode to the cathode but also, importantly, as a binder, gas transporter, and proton transfer agent within the catalyst layer. However, in the preparation of traditional catalyst slurries, the perfluorosulfonic acid ionomers, particularly Nafion derivatives, which act as proton transfer agents in the catalyst layer, need to be mixed with the Pt catalyst. After ultrasonic dispersion, they directly contact the Pt catalyst particle surface, forming a three-phase reaction interface (mass, liquid, gas). However, in the dried catalyst layer, the ionomers, existing as a thin film on the Pt surface, can be separated by the sulfonic acid groups (-SO4) at the end of their side chains. 3- Oxygen atoms in sulfonic acid groups specifically adsorb onto the Pt surface. The poisoning effect of sulfonic acid groups on the Pt surface can be as high as 80% of the catalyst's mass activity. Therefore, reducing the toxicity of sulfonic acid groups to the Pt catalyst surface to decrease the amount of Pt catalyst used is of great significance for improving fuel cell performance. Furthermore...

[0003] To address the aforementioned issues, many researchers have conducted extensive research on the design of Pt catalysts and catalyst inks. The literature [Electroanal.chem., 2020, 871:114250] by Tomohiro Takeshita et al. at the Toyota Motor Research Center Laboratory found that because ionomers such as Nafion have difficulty penetrating the internal pores of porous carbon supports, porous carbon-supported Pt catalysts have significantly lower ionomer coverage than non-porous carbon-supported Pt catalysts. Therefore, depositing Pt particles inside the porous carbon support reduces direct contact with the sulfonic acid groups of the ionomers. However, this still cannot prevent the poisoning effect of the ionomers on the catalyst. Patent CN114583227A discloses a method for preparing membrane electrodes by printing different catalyst layers, each layer being a mixture of different catalysts, resin solutions, and solvents, layered to form a more customized membrane electrode structure. However, the prepared catalyst layers still require the retention of ionomers to construct the three-phase reaction interface, still failing to prevent the poisoning effect of ionomers on the Pt catalyst, leading to catalyst deactivation. In addition, the incorporation of ionomers can easily cause catalyst agglomeration. Ionomers can coat catalyst particles, preventing the active sites from being fully exposed, which in turn affects the performance of the catalyst layer.

[0004] In addition, other aspects of catalyst ink preparation also need to consider whether the ink's flowability allows for successful inkjet printing of the catalyst layer, avoiding ink clogging of the printhead. Patent CN112980247A discloses a high-stability inkjet printing ink for fuel cells prepared by mixing a catalyst, solvent, binder, chelating agent, and resin solution. Literature [Electrochimica Acta 156(2015)289-300] reports an inkjet printing ink composed of a catalyst, isopropanol, glycerol, and resin solution, which can successfully prepare the catalyst layer through inkjet printing. Although the above inkjet printing ink solutions can be well applied to inkjet printers, the presence of binders, chelating agents, and other substances in the ink may have unknown negative effects on the catalyst. Therefore, the two existing problems should be addressed: firstly, avoiding catalyst agglomeration caused by the ionomers in the catalyst layer coating the catalyst and the poisoning effect of the ionomers on the catalyst; secondly, avoiding the addition of binders, chelating agents, surfactants, and other substances to the inkjet ink. Summary of the Invention

[0005] To address one or more of the above-mentioned problems, this invention provides a method for constructing high-precision catalytic layer mass transfer channels.

[0006] The high-precision catalyst layer mass transfer channel construction method of the present invention includes:

[0007] Step 1 involves configuring the ink, including:

[0008] Catalyst ink A was prepared by mixing solvent and catalyst at a mass ratio of (0-1):(0-1).

[0009] Ionomer ink B was prepared by mixing solvent and ionomer at a mass ratio of (0-1):(0-1).

[0010] Functional ink C was prepared by mixing solvent and additive in a mass ratio of (0-1):(0-1);

[0011] Step 2 involves the construction of high-precision catalytic layer mass transfer channels, including:

[0012] A multi-layered catalyst layer is formed, wherein the plane containing each layer is a forming plane, during which:

[0013] Using an inkjet printing device, in different areas of the same catalyst layer forming plane, any two of the following inks are used alternately for printing: catalyst ink A, ionomer ink B, or functional ink C. The patterns printed by the different inks are spliced ​​together to form a composite layer.

[0014] Multiple composite layers are printed in a stacked manner, wherein at least one composite layer is printed by catalyst ink A and ionomer ink B.

[0015] Furthermore, it also includes printing a functional layer using functional ink C alone on a certain shaped plane.

[0016] Furthermore, between adjacent composite layers, the areas printed by the same ink are staggered in the horizontal direction.

[0017] Furthermore, the composite layer is formed on a substrate material layer, wherein the substrate material is a proton exchange membrane or anion exchange membrane.

[0018] Furthermore, the solvent is one or a mixture of isopropanol and water;

[0019] Furthermore, the additive is one or more of the following: pore-forming agent, hydrophilic agent, hydrophobic agent, and conductive agent;

[0020] Furthermore, the catalyst is one or more of platinum-based catalysts, non-precious metal catalysts, and carbon-based catalysts;

[0021] Furthermore, the platinum-based catalyst is platinum black, platinum carbon, or a nanostructured platinum-based catalyst;

[0022] Furthermore, the ionomer is one or a mixture of perfluorosulfonic acid resin solutions of any concentration, biphenyl, and terphenyl.

[0023] Furthermore, the preparation process of the catalyst ink A, ionomer ink B and / or functional ink C includes: first, mixing one or more solvents and stirring in a constant temperature water bath at 20-50 degrees Celsius for 15-120 minutes; then dispersing the solute into the solvent mixture; then sonicating the mixture at 20-30 degrees Celsius for 15-120 minutes; then pulverizing cells at 20-30 degrees Celsius for 15-120 minutes; and finally stirring in a constant temperature water bath at 25-35 degrees Celsius for 10-15 hours.

[0024] After adopting the above technical solution, the present invention mainly has the following effects:

[0025] (1) The catalyst layer involved in the preparation method of the present invention separates the catalyst particles from the ionomer, avoids the poisoning effect of the ionomer on the catalyst particles, reduces the activity loss of the catalyst, and improves the output performance of the membrane electrode.

[0026] (2) The catalyst ink A, ionomer ink B and functional ink C involved in the preparation method of the present invention do not contain binders, surfactants or solvents that have adverse effects on the catalyst layer. They only contain solvents and catalysts or resin solutions. The inks involved can be sprayed through the nozzles, which effectively reduces the agglomeration of catalysts in the solution.

[0027] (3) By designing a single-layer composite layer structure, this method can print inks A, B, and C in different regions on the substrate material, and can also print inks of different functions at the same time. This avoids the phenomenon that the catalyst is coated by the ionomer and cannot contact the reaction gas well during the mixing of the ionomer and the catalyst, and also avoids the phenomenon that the catalyst is poisoned by the ionomer. On the other hand, the catalyst ink region and the ionomer ink region that are spliced ​​together form a mass transfer-friendly ionomer channel on a macroscopic level, replacing the ionomer channel originally established at the microscopic level. This ensures that a macroscopic three-phase reaction interface is constructed on the catalyst layer, forming a mass transfer channel, thereby optimizing the structure of the catalyst layer.

[0028] This invention enables inkjet printing inks with catalyst layers composed solely of solvents and catalysts. This avoids the effects of catalyst poisoning by ionomers and eliminates the adverse effects of irrelevant binders and surfactants. Furthermore, inkjet printing is used to construct a membrane electrode with cross-linked catalyst and ionomer layers, forming a macroscopic three-phase reaction interface that replaces the original microscopic three-phase reaction interface. This reduces the risk of printhead clogging due to catalyst agglomeration, lowers the complexity of ink preparation, and effectively constructs a membrane electrode consisting of functional layers such as a catalyst layer, a mass transfer layer, and a hydrophobic layer.

[0029] This invention is simple to operate and enables the mass production of membrane electrodes containing catalytic layers with mass transfer channels. The membrane electrodes prepared using this invention exhibit excellent battery performance. By using specific inks for printing, multiple catalytic layers with different functional structures can be printed simultaneously. High-precision printing of mass transfer channels optimizes the mass transfer process of the catalytic layers, improves reaction efficiency, and holds promise as a replacement for traditional fabrication processes in fuel cells. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the integrated printhead containing different ink tanks in an embodiment of the present invention.

[0031] Figure 2 This is a planar schematic diagram of the composite layer printed in Embodiment 1 of the present invention.

[0032] Figure 3 This is a planar schematic diagram of the composite layer printed in Embodiment 2 of the present invention.

[0033] Figure 4 This is a planar schematic diagram of the composite layer printed in Embodiment 3 of the present invention.

[0034] Figure 5 This is a cross-sectional view of the catalytic layer printed in some other embodiments of the present invention.

[0035] Figure 6 This is a cross-sectional view of the catalytic layer printed in some embodiments of the present invention.

[0036] Figure 7 The electrochemical performance test curves of the membrane electrode prepared by the fuel cell inkjet printing ink obtained in Example 1 and Comparative Example 1 of the present invention when it is used as the anode of the membrane electrode fuel cell.

[0037] Curve 1 is the voltage-current density relationship curve of the membrane electrode prepared by the fuel cell inkjet printing ink obtained in Example 1, and curve 2 is the voltage-current density relationship curve corresponding to Comparative Example 1.

[0038] Figure 8 The membrane electrode prepared using the fuel cell inkjet printing ink obtained in Example 1 and Comparative Example 1 of this invention is used as the membrane electrode anode of a fuel cell.

[0039] Curve 1 is the mass power-current density relationship curve of the membrane electrode prepared by the fuel cell inkjet printing ink obtained in Example 1, and curve 2 is the mass power-current density relationship curve corresponding to Comparative Example 1. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments.

[0041] The catalysts, solvents, and resin solutions used in the experimental embodiments of this invention are all commercially available products. The following examples illustrate the fabrication process of inkjet-printed film electrodes using different embodiments.

[0042] In the following and more embodiments of the present invention, each printing channel on the inkjet printing device is equipped with inks A, B, and C that constitute the catalyst layer components. Catalyst ink A corresponds to the catalyst layer, ionomer ink B corresponds to the ionomer layer, and functional ink C corresponds to the functional layer. During inkjet printing, when printing the composite layer, ink A is selected to print the catalyst layer A on the plane. Within the same level, catalyst layer A and ionomer layer B are adjacent in the x-axis direction, forming an ABABA structure. The number of catalyst layers A and ionomer layers B can be selected according to actual needs to form a composite layer. Similarly, the second level can form an ABABA or BABAB structure in the x-axis direction, so that the composite layer contains a catalyst layer and a mass transfer layer macroscopically.

[0043] During inkjet printing, when printing the composite layer, ink A is selected to print the catalyst layer A on the plane. Within the same level, the catalyst layer A and the ionomer layer B are adjacent in the x-axis direction, forming an ABABA structure. The number of catalyst layers A and ionomer layers B can be selected according to actual needs to form a composite layer. Similarly, the second level can form an ABABA or BABAB, ACACA or CACAC, BCBCB or CBCBC structure in the y-axis direction, so that the composite layer contains a catalyst layer, a mass transfer layer and a functional layer on a macroscopic scale.

[0044] Functional layer C can be printed independently in any composite layer, or it can be combined with layers A and B to form an ABC interlaced composite layer structure.

[0045] Because the composite single-layer planar structure forms an interpenetrating ionomer and catalyst, and the three-dimensional structure is covered layer by layer as an integral membrane electrode structure, it avoids the problem of the catalyst being coated by the ionomer and unable to properly contact the reactant gas during the mixed spraying of ionomer and catalyst, and also avoids the phenomenon of catalyst poisoning by the ionomer. Macroscopically, it also constructs ionomer channels that are beneficial for mass transfer. This allows for the high-precision construction of catalyst layers, ionomer layers, and functional layers. Different inks are sprayed onto the substrate surface at different position coordinates, and one or more inks can be sprayed simultaneously to design an ideal catalyst layer.

[0046] Due to the unique nature of inkjet printers, single or multiple ink channels can be sprayed simultaneously. During the inkjet process, one or more inks from the ink tank can be deposited together on the substrate material, and the combination of the catalyst and resin solution is varied and controllable. This mixing method also reduces the agglomeration of the catalyst in the ink components caused by the resin solution encapsulating it.

[0047] Examples 1-3 exemplarily illustrate the specific configuration process and printing method of the ink in this invention.

[0048] Example 1

[0049] The method for preparing an inkjet-printed membrane electrode for a fuel cell in this embodiment includes the following steps:

[0050] (1) Prepare slurry ink A, slurry ink B, and slurry ink C:

[0051] Ink A: At room temperature, the organic mixed solvent and Pt / C catalyst (60 wt%) have a mass ratio of 23:55. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred for 15 minutes in a 20°C constant-temperature water bath. The mixture obtained in the above process is then added to 60 wt% Pt / C, and the mixture is ultrasonically treated in a 20°C water bath for 15 minutes to mix thoroughly. Afterward, the mixture is subjected to cell disruption ultrasonication for 15 minutes at 20°C, and finally stirred in a 25°C constant-temperature water bath for 10 hours to obtain the fuel cell inkjet printing ink A of this example.

[0052] Ink B: At room temperature, the organic mixed solvent and perfluorosulfonic acid resin solution (5wt%) are mixed at a mass ratio of 471. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 20°C constant temperature water bath for 15 minutes. The mixture obtained in the above process is added to 5% resin solution in proportion, and then ultrasonically treated in a 20°C water bath for 15 minutes to mix evenly. After that, the cells are ultrasonically disrupted at 20°C for 15 minutes. Finally, the mixture is stirred in a 25°C constant temperature water bath for 10 hours to obtain the fuel cell inkjet printing ink B of this example.

[0053] Ink C: At room temperature, the organic mixed solvent to graphene mass ratio is 0.2. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred for 15 minutes in a 20°C constant-temperature water bath. The mixture obtained in the above process is then added to 60wt% Pt / C, and the mixture is ultrasonically treated in a 20°C water bath for 15 minutes to mix thoroughly. Next, the mixture is subjected to cell disruption ultrasonication at 20°C for 15 minutes. Finally, it is stirred in a 25°C constant-temperature water bath for 10 hours to obtain the inkjet printing ink C for fuel cells in this example.

[0054] (2) Construction of high-precision catalytic layer mass transfer channels:

[0055] like Figure 2 As shown, during inkjet printing, when printing the composite layer, ink A is selected to print the catalyst layer A on the plane. Within the same layer, the catalyst layer A and the ionomer layer B are adjacent in the x-axis direction, forming an ABABA composite layer. Similarly, in the second layer, the ionomer layer B and the functional layer C are also adjacent in the x-axis direction, forming a BCBCB composite layer, and so on, stacking them repeatedly.

[0056] Example 2

[0057] The method for preparing an inkjet-printed membrane electrode for a fuel cell in this embodiment includes the following steps:

[0058] (1) Prepare slurry ink A, slurry ink B, and slurry ink C:

[0059] Ink A: At room temperature, the organic mixed solvent and Pt / C catalyst (60 wt%) have a mass ratio of 10:56. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 35°C constant-temperature water bath for 75 minutes. The mixture obtained in the above process is then added to 60 wt% Pt / C, and the mixture is ultrasonically treated in a 25°C water bath for 75 minutes to mix thoroughly. Next, the mixture is ultrasonically treated at 25°C for 75 minutes to disrupt cell structure. Finally, it is stirred in a 30°C constant-temperature water bath for 12.5 hours to obtain the fuel cell inkjet printing ink A of this example.

[0060] Ink B: At room temperature, the organic mixed solvent and perfluorosulfonic acid resin solution (5wt%) are mixed in a mass ratio of 2:3:2. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 35°C constant temperature water bath for 75 minutes. The mixture obtained in the above process is then added to 5% resin solution, and the mixture is ultrasonically treated in a 25°C water bath for 75 minutes to mix evenly. After that, the mixture is ultrasonically treated to disrupt cells at 25°C for 75 minutes. Finally, the mixture is stirred in a 30°C constant temperature water bath for 12.5 hours to obtain the fuel cell inkjet printing ink B of this example.

[0061] Ink Slurry C: At room temperature, the organic mixed solvent to graphene mass ratio is 0.35. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 30°C constant temperature water bath for 75 minutes. Then, the mixture is stirred in a 35°C constant temperature water bath for 75 minutes. The resulting mixture is then added to graphene in a specific ratio, and the mixture is ultrasonically treated in a 25°C water bath for 75 minutes to ensure homogeneity. Finally, the mixture is ultrasonically treated at 25°C for 75 minutes to disrupt cell structure. The final mixture is stirred in a 30°C constant temperature water bath for 12.5 hours to obtain the fuel cell inkjet printing ink C of this example.

[0062] (3) Construction of high-precision catalytic layer mass transfer channels:

[0063] During inkjet printing, when printing the composite layer, ink A is selected to print catalyst layer A on the plane. Within the same layer, catalyst layer A and ionomer layer B form a serpentine structure, combining to form the composite layer. In the second layer, ionomer layer B and functional layer C also form a serpentine structure, and this process is repeated.

[0064] Example 3

[0065] The method for preparing an inkjet-printed membrane electrode for a fuel cell in this embodiment includes the following steps:

[0066] (1) Prepare slurry ink A, slurry ink B, and slurry ink C:

[0067] Ink A: At room temperature, the organic solvent and Pt / C catalyst (60wt%) are mixed at a mass ratio of 23:55. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 50°C constant temperature water bath for 120 minutes. The mixture obtained in the above process is then added to 60wt% Pt / C, and the mixture is ultrasonically treated in a 30°C water bath for 120 minutes to mix thoroughly. Cell disruption is then ultrasonically treated at 30°C for 120 minutes. Finally, the mixture is stirred in a 35°C constant temperature water bath for 15 hours to obtain the fuel cell inkjet printing ink A of this example.

[0068] Ink B: At room temperature, the organic mixed solvent and perfluorosulfonic acid resin solution (5wt%) are mixed at a mass ratio of 107. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 50°C constant temperature water bath for 120 minutes. The mixture obtained in the above process is then mixed with 5% resin solution in a water bath at 30°C for 120 minutes to achieve uniform mixing. After that, the mixture is subjected to cell disruption and ultrasonication at 30°C for 120 minutes. Finally, it is stirred in a 35°C constant temperature water bath for 15 hours to obtain the inkjet printing ink B for fuel cells in this example.

[0069] Ink C: At room temperature, the organic mixed solvent to graphene mass ratio is 0.5. Isopropanol and water are first mixed at a volume ratio of 4:1 and stirred in a 50°C constant temperature water bath for 120 minutes. The mixture obtained in the above process is then added to graphene in proportion, and the mixture is ultrasonically treated in a 30°C water bath for 120 minutes to mix thoroughly. Next, the mixture is ultrasonically treated at 30°C for 120 minutes to disrupt cell structure. Finally, it is stirred in a 35°C constant temperature water bath for 15 hours to obtain the fuel cell inkjet printing ink C of this example.

[0070] (4) Construction of high-precision catalytic layer mass transfer channels:

[0071] During inkjet printing, when printing the composite layer, ink A is selected to print the catalyst layer A on the plane. Within the same layer, the catalyst layer A and the ionomer layer B are adjacent in the y-axis direction, forming an ABABA composite layer structure. In the second layer, the ionomer layer B and the functional layer C are also adjacent in the y-axis direction, forming a BCBCB composite layer, and so on, stacking them repeatedly.

[0072] In addition to the ink arrangement methods in the three embodiments above, in other embodiments of the present invention, such as... Figure 5 As shown, a single-material functional layer C is also printed in a molded sheet using functional ink C alone;

[0073] In some other embodiments of the present invention, the areas printed by the same ink in adjacent composite layers are staggered in the horizontal direction, for example... Figure 6 In the embodiment shown, the catalyst layer A in the lower composite layer is horizontally offset from the catalyst layer A in the upper composite layer. Similarly, the ionomer layers B in the upper and lower composite layers are also offset.

[0074] In other embodiments, the additive is one or more of the following: pore-forming agents, hydrophilic agents, hydrophobic agents, and other conductive agents.

[0075] In other embodiments, the catalyst may be one or a mixture of platinum-based catalysts, non-precious metal catalysts, and carbon-based catalysts; the platinum-based catalyst may be platinum black, platinum carbon, or nanostructured platinum-based catalyst.

[0076] In other embodiments, the ionomer may also be a solution of perfluorosulfonic acid resin of any concentration, biphenyl, terphenyl, or a mixture of one or more of these.

[0077] The composite layer is printed on the basis of the substrate material layer, which can be a proton exchange membrane or an anion exchange membrane.

[0078] Comparative Example 1

[0079] The method for fabricating an inkjet-printed membrane electrode for a fuel cell in this example includes the following steps:

[0080] (1) Ink preparation:

[0081] At room temperature, isopropanol:Pt / C catalyst (60wt%) was prepared at a mass ratio of 6:2:8 and ultrasonicated in a water bath for 30 minutes at room temperature. Then, Pt / C catalyst:perfluorosulfonic acid resin solution (5%) was prepared at a mass ratio of 0.2. The mixture obtained in the above process was added to 5% resin solution and ultrasonicated in a water bath at room temperature for 15 minutes to mix evenly, thus obtaining the conventional fuel cell ink in this comparative example.

[0082] (2) Preparation of the catalyst layer:

[0083] First, lay the base film flat on the heating equipment platform, peel off the protective layer on the surface, fix it on the equipment platform, inject the catalyst ink from step (1) into the pneumatic spray gun, the heating plate temperature is 60 degrees Celsius, spray it on the base film to obtain one electrode of the catalyst layer; the other side is prepared in the same way.

[0084] Performance testing

[0085] Test (1) Performance testing of membrane electrode assemblies (MEAs) for fuel cells prepared with simple inkjet printing ink

[0086] The cathode was prepared by weighing 0.2 mg of a commercial platinum-carbon catalyst and adding it to 1000 μL of isopropanol. After ultrasonic dispersion for 30 minutes, the mixture was evenly sprayed onto carbon paper using a spray gun on a 60°C heated plate. The anode was prepared by weighing the fuel cell inkjet printing ink prepared in Example 1 and evenly spraying it onto the proton exchange membrane using a printhead on an inkjet printer. The membrane electrode assembly was then performed using a Scribner 850e fuel cell testing system. The test conditions were: a battery temperature of 80°C, an anode humidified at 80°C, and a cathode humidified at 80°C. The inlet air for both the anode and cathode was O2 / H2, and the pressure was 200 kPa.

[0087] Test result comparison:

[0088] Figure 7 The electrochemical performance curves of the membrane electrode fuel cells prepared using Example 1 and Comparative Example 1 are shown. Figure 7 As can be seen from the curve corresponding to Example 1, at a voltage of 0.67V, the current density curve of Example 1 is significantly higher than that of Comparative Example 1. Figure 8 The image shows the power density curves of the two membrane electrode fuel cells. It can be seen that the power density (mass power) of the membrane electrode prepared in Example 1 is significantly higher than that of the membrane electrode prepared in Comparative Example 1, with a peak power of 1.6 W / cm². 2 This demonstrates that the high-precision construction of the catalyst layer mass transfer channel in Example 1 is feasible for use in the field of fuel cells, and exhibits excellent performance.

[0089] Compared to existing technologies, the catalyst layer constructed with high-precision mass transfer channels has better electrochemical performance, excellent stability, and higher fuel cell power.

[0090] Currently, most methods to address the poisoning effect of ionomers on catalysts focus on reducing the direct contact between the catalyst and the sulfonic acid groups of the ionomer at the microscopic level of the catalyst structure. However, from a macroscopic perspective, printing a composite layer containing both a catalyst layer and an ionomer layer at a single-layer level could not only reduce ionomer poisoning but also increase the surface area of ​​contact between the catalyst layer, the ionomer layer, and the gas. This would allow the ionomer, existing independently without mixing with the catalyst layer, to construct novel proton transport channels within the catalyst layer. This would reduce the direct contact between the ionomer and the catalyst from the ink preparation stage without weakening the proton transport channels. For catalyst inks, inkjet printing ink formulations often include binders, surfactants, or chelating agents. While the addition of these solvents can improve the dispersibility and stability of the ink, it may have unknown negative effects on the catalyst, catalyst layer, or membrane electrode assembly.

[0091] In summary, this invention provides a method for constructing a catalyst layer, which constructs a composite layer combining a catalyst layer and an ionomer layer from a macroscopic perspective. This avoids the poisoning effect on the catalyst caused by direct mixing of the ionomer and the catalyst. Furthermore, the ink does not contain binders, and the ionomer layer can still provide mass transfer channels for the catalyst layer. This opens up a new path for catalyst layer preparation at the macroscopic level.

Claims

1. A method for constructing high-precision catalytic layer mass transfer channels, characterized in that, include: Step 1: Configure the ink, including: Catalyst ink A was prepared by mixing solvent and catalyst at a mass ratio of (0-1):(0-1). Ionomer ink B was prepared by mixing solvent and ionomer at a mass ratio of (0-1):(0-1). Functional ink C was prepared by mixing solvent and additive in a mass ratio of (0-1):(0-1); Step 2: Construction of high-precision catalytic layer mass transfer channels, including: A multi-layered catalyst layer is formed, wherein the plane containing each layer is a forming plane, during which: Using an inkjet printing device, in different areas of the same catalyst layer forming plane, any two of the following inks are used alternately for printing: catalyst ink A, ionomer ink B, or functional ink C. The patterns printed by the different inks are spliced ​​together to form a composite layer. Multiple composite layers are printed in a stacked manner, wherein at least one composite layer is printed by catalyst ink A and ionomer ink B.

2. The method according to claim 1, characterized in that, Step 2 also includes printing a functional layer on a specific molding plane using functional ink C.

3. The method according to claim 1, characterized in that, In step 2, the areas printed by the same ink in adjacent composite layers are staggered in the horizontal direction.

4. The method according to claim 1, characterized in that, In step 2, the composite layer is formed on a substrate material layer, and the substrate material is a proton exchange membrane or anion exchange membrane.

5. The method according to claim 1, characterized in that, In step 1, the solvent is one or a mixture of isopropanol and water.

6. The method according to claim 1, characterized in that, In step 1, the additive is one or more of the following: pore-forming agent, hydrophilic agent, hydrophobic agent, and conductive agent.

7. The method according to claim 1, characterized in that, In step 1, the catalyst is one or more of platinum-based catalysts, non-precious metal catalysts, or carbon-based catalysts, or a mixture thereof.

8. The method according to claim 7, characterized in that, The platinum-based catalyst is platinum black, platinum carbon, or other nanostructured platinum-based catalysts.

9. The method according to claim 1, characterized in that, In step 1, the ionomer is one or more of perfluorosulfonic acid resin solutions of any concentration, biphenyl, and terphenyl.

10. The method according to claim 1, characterized in that, In step 1, the preparation process of the catalyst ink A, ionomer ink B, and / or functional ink C includes: first, mixing one or more solvents and stirring in a constant temperature water bath at 20-50 degrees Celsius for 15-120 minutes; then dispersing the solute into the solvent mixture; then sonicating the mixture at 20-30 degrees Celsius for 15-120 minutes; then pulverizing cells at 20-30 degrees Celsius for 15-120 minutes; and finally stirring in a constant temperature water bath at 25-35 degrees Celsius for 10-15 hours.

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