Membrane electrode and preparation method, system and application thereof

Abstract

The invention provides a membrane electrode and a preparation method, system and application thereof, and the preparation method of the membrane electrode comprises the following steps: carrying out heat-moisture treatment on a dried anode catalyst coating and a dried cathode catalyst coating to obtain a first anode catalyst coating and a first cathode catalyst coating; respectively carrying out first drying and second drying on the anode catalyst coating subjected to the heat-moisture treatment and the cathode catalyst coating subjected to the heat-moisture treatment to obtain a second anode catalyst coating and a second cathode catalyst coating; and laminating the second anode catalyst coating, a proton exchange membrane and the second cathode catalyst coating, and carrying out rolling transfer printing to obtain the membrane electrode. The membrane electrode catalyst layer prepared by the preparation method of the membrane electrode is tightly connected with the proton exchange membrane, so that the ion transmission resistance can be reduced, the mechanical strength of connection of a membrane electrode assembly is improved, meanwhile, the poisoning of alcohol to a platinum catalyst is reduced, and the consistency of the membrane electrode is obviously improved.

Description

Technical Field

[0001] This application relates to the technical field of fuel cells, and particularly relates to a membrane electrode, a preparation method thereof, a system and an application thereof. Background Art

[0002] The core component of a fuel cell or a water electrolyzer is a membrane electrode. Currently, the preparation of a membrane electrode can be divided into three methods: the decal transfer method, the CCM (catalyst-coated membrane) method, and the GDL method. In the decal transfer method, generally, a catalyst slurry is first coated on a transfer substrate, then dried to form a catalytic layer, and then it is combined with a proton exchange membrane through hot pressing, and the transfer substrate is removed to realize the transfer of the catalytic layer from the transfer substrate to the proton exchange membrane.

[0003] Currently, roll-to-roll transfer generally controls the transfer pressure and temperature to achieve good adhesion between the catalytic layer and the proton membrane layer. Currently, measures to improve the adhesion effect include adding a support sheet to reduce thickness fluctuations (CN117219791A - A transfer method and a transfer system for a coating), pre-coating a resin layer on the catalytic layer (CN118156521A - A preparation method for a high ion-conducting membrane electrode), etc. However, there is no relevant report on the influence of the differences in the alcohol and water content in the coating on the performance of the membrane electrode. Alcohol such as n-propanol, ethanol, isopropanol, etc. is used in the catalyst slurry. A small amount of these alcohols will remain in the coating during the drying process of the catalyst, which may have a certain impact on the catalyst activity. In addition, the roll-to-roll transfer time of high-speed roll-to-roll is short, and the influence of the water volatilization between the coating and the proton membrane on the heat during the transfer process cannot be ignored. Summary of the Invention

[0004] Aiming at the problems existing in the preparation of a membrane electrode by the roll-to-roll transfer method, such as poor adhesion between the catalyst layer and the proton exchange membrane, blocked ion conduction, and the influence of alcohol residues on the catalyst activity, an object of this application is to provide a preparation method for a membrane electrode. By treating the catalyst coating in a humid and hot environment (i.e., humid and hot treatment), the alcohol content in the coating is reduced, thereby reducing the poisoning effect of alcohol on platinum. At the same time, a drying process is added before roll-to-roll transfer, further reducing the alcohol and water content in the coating, improving the interfacial adhesion degree between the catalytic layer and the proton exchange membrane, reducing the internal resistance of the membrane electrode, and improving the performance consistency of the membrane electrode. This method has simple process steps, is easy to achieve batch preparation, and has high production efficiency.

[0005] Another object of this application is to provide a preparation system for a membrane electrode.

[0006] Another object of this application is to provide a membrane electrode.

[0007] Another object of this application is to provide a fuel cell.

[0008] For this reason, a first aspect of the present application provides a method for preparing a membrane electrode, including:

[0009] Performing hydrothermal treatment on the dried anode catalyst coating and the dried cathode catalyst coating to obtain a first anode catalyst coating and a first cathode catalyst coating;

[0010] Performing first drying and second drying on the hydrothermally treated anode catalyst coating and the hydrothermally treated cathode catalyst coating respectively to obtain a second anode catalyst coating and a second cathode catalyst coating;

[0011] Bonding the second anode catalyst coating, the proton exchange membrane, and the second cathode catalyst coating and then performing roll-to-roll transfer printing to obtain the membrane electrode.

[0012] In some embodiments, the temperature of the hydrothermal treatment is 20 - 80 °C.

[0013] In some embodiments, the humidity of the hydrothermal treatment is 40 - 100%.

[0014] In some embodiments, the time of the hydrothermal treatment is 3 - 30 days.

[0015] In some embodiments, the temperatures of the first drying and the second drying are both 50 - 150 °C.

[0016] In some embodiments, the first drying and the second drying are performed synchronously.

[0017] In some embodiments, the moving speed of the first anode catalyst coating during the first drying is 0.1 - 2.0 m / min.

[0018] In some embodiments, the moving speed of the first cathode catalyst coating during the second drying is 0.1 - 2.0 m / min.

[0019] In some embodiments, the transfer printing is roll-to-roll transfer printing.

[0020] A second aspect of the present application provides a membrane electrode preparation system, which is applied to the method for preparing a membrane electrode of the present application, including a transfer printing mechanism, a cathode catalyst layer unwinding device, an anode catalyst layer unwinding device, and a proton exchange membrane unwinding device for providing the proton exchange membrane. The cathode catalyst layer unwinding device is used to provide the first cathode catalyst coating, and the anode catalyst layer unwinding device is used to provide the first anode catalyst coating;

[0021] The membrane electrode preparation system further includes:

[0022] An anode catalyst coating drying device is used to perform the first drying on a first anode catalyst coating unwound from the anode catalyst layer, and feed the obtained second anode catalyst coating into the roll-transfer printing mechanism for roll-transfer printing.

[0023] A cathode catalyst coating drying device is used to perform the second drying on a first cathode catalyst coating unwound from the cathode catalyst layer, and feed the obtained second cathode catalyst coating into the roll-transfer printing mechanism for roll-transfer printing.

[0024] The third aspect of the present application provides a membrane electrode, which is prepared by using the preparation method of the membrane electrode described in the present application or the preparation system of the membrane electrode described in the present application.

[0025] The fourth aspect of the present application provides a fuel cell, which includes the membrane electrode described in the present application.

[0026] The preparation method of the membrane electrode described in the present application can at least bring the following beneficial effects:

[0027] By treating the catalyst coating in a humid and hot environment (i.e., humid and hot treatment), the alcohol content in the coating is reduced, thereby reducing the poisoning effect of alcohol on platinum. At the same time, a drying process is added before roll-transfer printing to further reduce the alcohol and water content in the coating, improve the interfacial adhesion degree between the catalytic layer and the proton exchange membrane, make the catalyst coating and the proton exchange membrane closely connected, increase the mechanical strength of the membrane electrode assembly connection, reduce the ion transport resistance, and thus reduce the internal resistance of the membrane electrode and improve the performance consistency of the membrane electrode. This method has simple process steps, is suitable for large-scale production (i.e., easy to achieve batch preparation), and has high production efficiency, which is beneficial to practical applications.

[0028] The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. Description of the Drawings

[0029] The above-mentioned and / or additional aspects and advantages of the present application will become obvious and easy to understand from the following description of the embodiments in conjunction with the drawings.

[0030] Wherein:

[0031] Figure 1 is a flowchart of the preparation method of the membrane electrode shown in an exemplary embodiment of the present application.

[0032] Figure 2 is a schematic structural diagram of the membrane electrode shown in an exemplary embodiment of the present application.

[0033] Figure 3 is a schematic structural diagram of the membrane electrode preparation system shown in an exemplary embodiment of the present application.

[0034] Figure 4 It is a comparative graph of polarization curves of the membrane electrodes prepared in Example 1 and Comparative Example 1, where: the one with the arrow pointing to the left represents the current density-voltage curve, and the one with the arrow pointing to the right represents the current density-internal resistance curve.

[0035] Figure 5 It is a comparative graph of DSC curves obtained by differential scanning calorimetry of the second cathode catalyst coating in Example 1 and the cathode catalyst coating in Comparative Example 1.

[0036] Figure 6 It is a comparative graph of thermogravimetric curves of the second cathode catalyst coating in Example 1 and the first cathode catalyst coating in Comparative Example 3.

[0037] Reference numerals:

[0038] 1 - CCM winding; 2 - cathode catalyst layer winding; 3 - roll pressing and transfer mechanism; 4 - cathode catalyst coating drying device; 5 - cathode catalyst layer unwinding; 6 - protective film unwinding; 7 - anode catalyst layer winding; 8 - anode catalyst coating drying device; 9 - proton exchange membrane unwinding; 10 - anode catalyst layer unwinding; 11 - protective film winding; 100 - cathode catalyst coating; 200 - proton exchange membrane; 300 - anode catalyst coating. Detailed implementation manners

[0039] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0040] In the present application, the disclosure of a numerical range includes all values within the entire range and the disclosure of further subdivided ranges, including the endpoints and sub-ranges given for these ranges.

[0041] In the present application, the raw materials, equipment, etc. involved, unless otherwise specified, are raw materials and equipment that can be obtained through commercial channels or prepared by known methods; the methods involved, unless otherwise specified, are conventional methods.

[0042] When the term "and / or" is used in a list containing two or more items, it means that any one of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression "A and / or B" is intended to mean A or B or A and B, that is, it only means A, only means B, or means the combination of A and B.

[0043] The inventors found that the existing roll-to-roll transfer time is relatively short (generally a few seconds). If the water content and alcohol content in the catalyst coating fluctuate, and the water content and alcohol content are high, the volatilization of water and alcohol will absorb heat, which will lead to poor fusion at the interface between the catalyst coating and the proton exchange membrane. Poor fusion will cause an increase in the internal resistance of the membrane electrode test. The large internal resistance of the membrane electrode is because the contact resistance at the interface between the catalyst coating and the proton exchange membrane is relatively large. After subjecting the produced catalyst coating to hydrothermal treatment and high-temperature drying, the water and alcohol content in the catalyst coating can be reduced, thereby improving the fusion performance at the interface between the catalyst coating and the proton exchange membrane, enhancing the adhesion, and reducing the internal resistance, etc.

[0044] The following describes a method for preparing a membrane electrode, a membrane electrode, and a preparation system for a membrane electrode according to an embodiment of the present application with reference to the accompanying drawings.

[0045] <Method for Preparing Membrane Electrode>

[0046] Figure 1 The flowchart of the method for preparing a membrane electrode shown in an exemplary embodiment of the present application.

[0047] As Figure 1 shown, the method for preparing the membrane electrode includes the following steps:

[0048] S101. Subject the dried anode catalyst coating and the dried cathode catalyst coating to hydrothermal treatment to obtain a first anode catalyst coating and a first cathode catalyst coating.

[0049] In the embodiment of the present application, the hydrothermal treatment refers to treating the dried anode catalyst coating and the dried cathode catalyst coating under certain temperature and humidity conditions for a certain period of time. By treating the catalyst coating in a hydrothermal environment (i.e., hydrothermal treatment), the alcohol content in the coating can be reduced, thereby reducing the poisoning effect of alcohol on platinum.

[0050] It should be noted that the dried anode catalyst coating and the dried cathode catalyst coating can be treated synchronously in a hydrothermal environment or separately.

[0051] In the embodiment of the present application, there is no limitation on the material composition of the dried anode catalyst coating and the dried cathode catalyst coating, and it can be any material containing platinum and suitable for the anode catalyst coating and the cathode catalyst coating well-known in the art.

[0052] Exemplarily, the composition of the dried anode catalyst coating includes perfluorosulfonic acid resin, platinum-carbon catalyst or platinum-cobalt catalyst, carbon powder, additives, etc., where the additives include but are not limited to at least one of cerium dioxide, iridium oxide, etc.

[0053] As an alternative example, the dried anode catalyst coating is composed of perfluorosulfonic acid resin and platinum-carbon catalyst, where: the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is 1:(2 - 4), and the platinum loading in the platinum-carbon catalyst is 50 - 70 wt%. Further preferably, the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is 1:3, and the platinum loading in the platinum-carbon catalyst is 60 wt%.

[0054] Exemplarily, the composition of the dried cathode catalyst coating includes perfluorosulfonic acid resin, platinum-carbon catalyst, platinum-cobalt catalyst, etc.

[0055] As an alternative example, the dried cathode catalyst coating is composed of perfluorosulfonic acid resin and platinum-carbon catalyst, where: the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is (3 - 5):(4 - 6), and the platinum loading in the platinum-carbon catalyst is 15 - 35 wt%. Further preferably, the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is 4:5, and the platinum loading in the platinum-carbon catalyst is 20 wt%.

[0056] In the embodiments of the present application, the dried anode catalyst coating and the dried cathode catalyst coating are the anode catalyst coating and the cathode catalyst coating obtained through normal production in the art, which can be self-made or obtained through commercial channels.

[0057] As an alternative example, the preparation methods of the dried anode catalyst coating and the dried cathode catalyst coating are the same, and both include the following steps:

[0058] (1) Prepare the catalyst slurry: uniformly disperse the constituent materials of the dried anode catalyst coating or the dried cathode catalyst coating in a dispersant to obtain the catalyst slurry.

[0059] (2) Coating: Coat the catalyst slurry on a substrate, and then dry it to obtain the dried anode catalyst coating or the dried cathode catalyst coating.

[0060] Exemplarily, in step (1), the dispersant includes but is not limited to at least one of ethanol, isopropanol, n-propanol, and water.

[0061] Exemplarily, in step (1), the solid content of the catalyst is 5 - 15%, including but not limited to 7.5%, 10%, or 12.5%, etc.

[0062] Exemplarily, in step (2), the substrate includes but is not limited to at least one of polytetrafluoroethylene (PTFE), etc.

[0063] Exemplarily, in step (2), the drying temperature is 70 - 90 °C, including but not limited to 75 °C, 80 °C, or 85 °C, etc., and preferably 80 °C, etc.

[0064] Exemplarily, in step (2), the drying time is 1 - 3 h, including but not limited to 1.5 h, 2 h, 2.5 h, etc.

[0065] In some embodiments, the temperature of the hydrothermal treatment is 20 - 80 °C, including but not limited to 30 °C, 50 °C, 70 °C, etc. When the temperature of the hydrothermal treatment is within the above range, the volatilization of the adsorbed alcohols in the catalyst layer can be accelerated without damaging the structure of the catalyst layer; when it is lower than 20 °C, it cannot reduce the adsorbed alcohol content; when it is higher than 80 °C, it reaches the glass transition temperature of the resin, damaging the pore structure of the catalyst layer.

[0066] As a preferred example, the temperature of the hydrothermal treatment is 40 - 60 °C.

[0067] In some embodiments, the humidity of the hydrothermal treatment is 40 - 100%, including but not limited to 50%, 70%, 90%, etc.

[0068] As a preferred example, the humidity of the hydrothermal treatment is 60 - 80%.

[0069] In some embodiments, the time of the hydrothermal treatment is more than 3 days, including but not limited to 5 days, 8 days, 10 days, etc.

[0070] Exemplarily, the time of the hydrothermal treatment is 3 - 30 days, including but not limited to 5 days, 10 days, 15 days, 20 days, 25 days, etc.

[0071] S102. Respectively perform first drying and second drying on the hydrothermally treated anode catalyst coating and the hydrothermally treated cathode catalyst coating obtained in step S101 to obtain a second anode catalyst coating and a second cathode catalyst coating.

[0072] In the embodiments of the present application, through the first drying and the second drying, the alcohol and water contents in the hydrothermally treated anode catalyst coating and the hydrothermally treated cathode catalyst coating can be further reduced, the interfacial adhesion degree between the catalyst layer and the proton exchange membrane can be improved, the internal resistance of the membrane electrode can be reduced, and the performance consistency of the membrane electrode can be improved.

[0073] In some embodiments, the temperatures of the first drying and the second drying are both 50 - 150 °C, including but not limited to 70 °C, 100 °C, 130 °C, etc.

[0074] In the embodiments of the present application, there is no limitation on the methods of the first drying and the second drying, which can be baking, spray drying, vacuum drying, etc.

[0075] As an optional example, the methods of the first drying and the second drying are both baking.

[0076] In some embodiments, the first drying and the second drying are carried out synchronously.

[0077] In some embodiments, during the first drying, the moving speed of the first anode catalyst coating is 0.1 - 2.0 m / min, including but not limited to 0.5 m / min, 1 m / min, or 1.5 m / min, etc.

[0078] In some embodiments, during the second drying, the moving speed of the first cathode catalyst coating is 0.1 - 2.0 m / min, including but not limited to 0.5 m / min, 1 m / min, or 1.5 m / min, etc.

[0079] In the embodiments of the present application, the moving speed in the first drying and the second drying refers to the speed at which the first anode catalyst coating and the first cathode catalyst coating move while being dried, that is, the feeding speed. It is the moving speed relative to their respective drying devices.

[0080] In some embodiments, the time for the first drying and the second drying is 5 min to 12 h, including but not limited to 1 h, 4 h, or 8 h, etc.

[0081] S103. After laminating the second anode catalyst coating, the proton exchange membrane, and the second cathode catalyst coating obtained in step S102, perform roll - to - roll transfer printing to obtain the membrane electrode.

[0082] It should be noted that in the embodiments of the present application, no limitation is imposed on the method and specific process parameters of transfer roll - pressing. Any transfer roll - pressing method applicable to the preparation of membrane electrodes in the art and its process parameter selection can be used.

[0083] As an optional example, the transfer roll - printing is roll - to - roll transfer roll - printing.

[0084] The method for preparing the membrane electrode in the embodiments of the present application treats the catalyst coating through a humid - heat environment treatment (i.e., humid - heat treatment), reduces the alcohol content in the coating, thereby reducing the poisoning effect of alcohol on platinum. At the same time, an additional drying process is added before roll - to - roll transfer printing, further reducing the alcohol and water content in the coating, improving the interfacial adhesion degree between the catalytic layer and the proton exchange membrane, making the connection between the catalyst coating and the proton exchange membrane tight, increasing the mechanical strength of the connection of the membrane electrode assembly, reducing the ion transport resistance, and thus reducing the internal resistance of the membrane electrode and improving the performance consistency of the membrane electrode. This method has simple process steps, is suitable for large - area production (i.e., easy to achieve batch preparation), and has high production efficiency, which is beneficial for practical applications.

[0085] <Preparation system of membrane electrode>

[0086] The preparation system of the membrane electrode according to the embodiment of the present application can be applied to the preparation method of the membrane electrode according to the embodiment of the present application.

[0087] It should be noted that the preparation system of the membrane electrode according to the embodiment of the present application is mainly based on the traditional preparation system for the roll printing and transfer pressing method of the membrane electrode. Before the transfer printing and rolling mechanism, drying devices for the anodic catalyst coating (i.e., the first anodic catalyst coating) and the cathodic catalyst coating (i.e., the first cathodic catalyst coating) after the humid heat treatment are added, namely the first drying device and the second drying device, which are used to perform high-temperature drying on the anodic catalyst coating and the cathodic catalyst coating after the humid heat treatment, so as to further reduce the content of alcohol and water in the coatings (i.e., the anodic catalyst coating and the cathodic catalyst coating), improve the interfacial adhesion degree between the catalytic layer and the proton membrane, reduce the internal resistance of the membrane electrode, and improve the performance consistency of the membrane electrode. Among them, the traditional preparation system for the roll printing and transfer pressing method of the membrane electrode can be any preparation system well-known in the art that can be used to prepare the membrane electrode by the roll printing and transfer pressing method of the membrane electrode.

[0088] Figure 3 It is a schematic structural diagram of the membrane electrode preparation system shown in an exemplary embodiment of the present application.

[0089] As Figure 3 shown, the membrane electrode preparation system includes a transfer printing and rolling mechanism 3, a cathodic catalyst layer unwinding device 5, an anodic catalyst layer unwinding device 10, and a proton exchange membrane unwinding device 9 for providing the proton exchange membrane. The cathodic catalyst layer unwinding device 5 is used to provide the first cathodic catalyst coating, and the anodic catalyst layer unwinding device 10 is used to provide the first anodic catalyst coating.

[0090] In some embodiments, the preparation system of the membrane electrode further includes an anodic catalyst coating drying device 8 and a cathodic catalyst coating drying device 4. Among them, the anodic catalyst coating drying device 8 is used to perform the first drying on the first anodic catalyst coating from the anodic catalyst layer unwinding device 10, and send the obtained second anodic catalyst coating into the roll printing and transfer mechanism 3 for roll printing and transfer; the cathodic catalyst coating drying device 4 is used to perform the second drying on the first cathodic catalyst coating from the cathodic catalyst layer unwinding device 5, and send the obtained second cathodic catalyst coating into the roll printing and transfer mechanism 3 for roll printing and transfer.

[0091] In some embodiments, the anodic catalyst coating drying device 8 is arranged between the anodic catalyst layer unwinding device 10 and the roll printing and transfer mechanism 3, and is located below the proton exchange membrane unwinding device 9 or at a position slightly lower in the middle.

[0092] In some embodiments, the cathode catalyst coating drying device 4 is arranged between the cathode catalyst layer unwinding 5 and the rotary press printing mechanism 3, and is located above the proton exchange membrane unwinding.

[0093] In some embodiments, both the anode catalyst coating drying device 4 and the cathode catalyst coating drying device 8 are drying devices including a plurality of material passing rollers and a hot air circulation system.

[0094] In some embodiments, the membrane electrode preparation system further includes a CCM winding 1, a cathode catalyst layer winding 2, a protective film unwinding 6, an anode catalyst layer winding 7, a protective film winding 11, etc.

[0095] It should be noted that in the embodiments of the present application, the structural designs of the CCM winding 1, the cathode catalyst layer winding 2, the roll pressing and transfer printing mechanism 3, the cathode catalyst coating drying device 4, the cathode catalyst layer unwinding 5, the protective film unwinding 6, the anode catalyst layer winding 7, the anode catalyst coating drying device 8, the proton exchange membrane unwinding 9, and the anode catalyst layer unwinding 10, their relative position settings, the connection relationships with each other, the working principles, etc. are all prior arts and will not be elaborated here.

[0096] <Membrane electrode>

[0097] The membrane electrode of the embodiment of the present application is prepared by using the membrane electrode preparation method of the embodiment of the present application, or is prepared by using the membrane electrode preparation system of the embodiment of the present application.

[0098] In some embodiments, as Figure 2 shown, the membrane electrode includes a cathode catalyst coating 100, a proton exchange membrane 200, and an anode catalyst coating 300 that are sequentially stacked.

[0099] It should be noted that the cathode catalyst coating 100, the proton exchange membrane 200, and the anode catalyst coating 300 that are sequentially stacked here are the products obtained by roll pressing and transfer printing after the second anode catalyst coating, the proton exchange membrane, and the second cathode catalyst coating are laminated in the membrane electrode preparation method of the embodiment of the present application, where: the cathode catalyst coating 100 corresponds to the second cathode catalyst coating, and the anode catalyst coating 300 corresponds to the second anode catalyst coating.

[0100] <Fuel cell>

[0101] The fuel cell of the embodiment of the present application includes the membrane electrode of the embodiment of the present application.

[0102] As an optional example, the fuel cell of the embodiment of the present application is a proton exchange membrane fuel cell.

[0103] The membrane electrode preparation system, membrane electrode, and fuel cell according to the embodiments of the present application all have at least the beneficial effects of the membrane electrode preparation method according to the embodiments of the present application.

[0104] Some features of the present technology are further illustrated in the following non-limiting examples.

[0105] The dried cathode catalyst coating and the dried anode catalyst coating involved in the following examples and comparative examples refer to the cathode catalyst coating and the anode catalyst coating obtained by normal existing production and drying, and their respective compositions and preparation methods are as follows:

[0106] The dried cathode catalyst coating is composed of perfluorosulfonic acid resin and platinum-carbon catalyst, wherein: the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is 1:3, and the platinum loading in the platinum-carbon catalyst is 60 wt%. The thickness of the dried cathode catalyst coating is 5 μm, and the platinum loading is 0.4 mg / cm 2 。

[0107] The preparation method of the dried cathode catalyst coating is: uniformly disperse perfluorosulfonic acid resin and platinum-carbon catalyst in a mixed solvent of anhydrous ethanol and deionized water with a mass ratio of 3:1 to obtain a cathode catalyst slurry with a solid content of 10%; subsequently, coat the cathode catalyst slurry on a polytetrafluoroethylene (PTFE) substrate and dry it at 80 °C for 2 h to obtain the dried cathode catalyst coating.

[0108] The dried anode catalyst coating is composed of perfluorosulfonic acid resin and platinum-carbon catalyst, wherein: the mass ratio of perfluorosulfonic acid resin to platinum-carbon catalyst is 4:5, and the platinum loading in the platinum-carbon catalyst is 20 wt%. The thickness of the dried anode catalyst coating is 3 μm, and the platinum loading is 0.056 mg / cm 2 。

[0109] The preparation method of the dried anode catalyst coating is: uniformly disperse perfluorosulfonic acid resin and platinum-carbon catalyst in a mixed solvent of anhydrous ethanol and deionized water with a mass ratio of 3:1 to obtain an anode catalyst slurry with a solid content of 10%; subsequently, coat the anode catalyst slurry on a polytetrafluoroethylene (PTFE) substrate and dry it at 80 °C for 2 h to obtain the dried anode catalyst coating.

[0110] Example 1

[0111] The preparation method of the membrane electrode in this example includes the following steps:

[0112] (1) Uniformly treat the dried cathode catalyst coating and the dried anode catalyst coating in an environment with a temperature of 50 °C and a humidity of 70% for 5 days to obtain a first cathode catalyst coating and a first anode catalyst coating.

[0113] (2) Dry the first cathode catalyst coating and the first anode catalyst coating obtained in step (1) at 100 °C for 12 h respectively to make them fully dry, obtaining the second cathode catalyst coating and the second anode catalyst coating.

[0114] (3) Place the second cathode catalyst coating and the second anode catalyst coating obtained in step (2) on both sides of the proton exchange membrane and bond them, and then perform roll printing to obtain the membrane electrode of this embodiment.

[0115] Among them, the proton exchange membrane is a G12 proton exchange membrane (a proton exchange membrane with a thickness of 12 μm produced by Gore); the process conditions for roll printing are: speed 1 m / min, temperature 165 °C.

[0116] Example 2 (compared with Example 1, the temperature, humidity and time of the damp heat treatment are all at the lower limits)

[0117] This example is basically the same as Example 1, the difference is that:

[0118] In step (1), the dried cathode catalyst coating and the dried anode catalyst coating are uniformly treated in an environment with a temperature of 20 °C and a humidity of 40% for 3 days.

[0119] Example 3 (compared with Example 1, the temperature, humidity and time of the damp heat treatment are all at the upper limits)

[0120] This example is basically the same as Example 1, the difference is that:

[0121] In step (1), the dried cathode catalyst coating and the dried anode catalyst coating are uniformly treated in an environment with a temperature of 80 °C and a humidity of 100% for 30 days.

[0122] Example 4 (compared with Example 1, the lower limit of the temperature, the upper limit of the humidity and the time of the damp heat treatment remain unchanged)

[0123] This example is basically the same as Example 1, the difference is that:

[0124] In step (1), the dried cathode catalyst coating and the dried anode catalyst coating are uniformly treated in an environment with a temperature of 20 °C and a humidity of 100% for 5 days.

[0125] Example 5 (compared with Example 1, the upper limit of the temperature, the lower limit of the humidity and the time of the damp heat treatment remain unchanged)

[0126] This example is basically the same as Example 1, the difference is that:

[0127] In step (1), the dried cathode catalyst coating and the dried anode catalyst coating are uniformly treated in an environment with a temperature of 80°C and a humidity of 40% for 5 days.

[0128] Example 6 (compared with Example 1, the temperature of high-temperature drying is the lower limit)

[0129] This example is basically the same as Example 1, except that:

[0130] In step (2), the first cathode catalyst coating and the first anode catalyst coating obtained in step (1) are dried at 50°C for 12 h respectively.

[0131] Example 7 (compared with Example 1, the temperature of high-temperature drying is the upper limit)

[0132] This example is basically the same as Example 1, except that:

[0133] In step (2), the first cathode catalyst coating and the first anode catalyst coating obtained in step (1) are dried at 160°C for 5 min respectively.

[0134] Example 8 (compared with Example 1, using the preparation system of the present application) Figure 3 of the present application)

[0135] This example is basically the same as Example 1, except that:

[0136] Adopt as Figure 3 shown in the preparation method of the membrane electrode to prepare the membrane electrode of this example, wherein:

[0137] In step (2), the first drying and the second drying are carried out synchronously. During the first drying, the moving speed of the first anode catalyst coating is 1 m / min; during the second drying, the moving speed of the first cathode catalyst coating is 1 m / min. The anode catalyst coating drying device 8 and the cathode catalyst coating drying device 4 are both drying devices including a plurality of material passing rollers and a hot air circulation system.

[0138] In step (3), the roll-to-roll roll pressing and transferring is carried out.

[0139] Comparative Example 1

[0140] In this comparative example, the dried cathode catalyst coating and the dried anode catalyst coating are used to prepare the membrane electrode. The preparation method of the membrane electrode is as follows:

[0141] The dried cathode catalyst coating and the dried anode catalyst coating are respectively placed on both sides of the proton exchange membrane and adhered, and then roll pressing and transferring is carried out to obtain the membrane electrode of this comparative example.

[0142] Among them, the proton exchange membrane is a G12 proton exchange membrane (a proton exchange membrane with a thickness of 12 μm produced by Gore), and the process conditions of roll-to-roll transfer printing are the same as those in Example 1.

[0143] Comparative Example 2 (compared with Example 1, without the step of damp heat treatment)

[0144] The preparation method of the membrane electrode of this comparative example includes the following steps:

[0145] (1) The dried cathode catalyst coating and the dried anode catalyst coating are respectively dried at 100 °C for 2 h to obtain the dried cathode catalyst coating and the dried anode catalyst coating.

[0146] (2) The dried cathode catalyst coating and the dried anode catalyst coating obtained in step (1) are respectively placed on both sides of the proton exchange membrane and adhered, and then roll-to-roll transfer printing is carried out to obtain the membrane electrode of this example.

[0147] Among them, the proton exchange membrane and the process conditions of roll-to-roll transfer printing are the same as those in Example 1.

[0148] Comparative Example 3 (compared with Example 1, without the step of high-temperature drying after damp heat treatment)

[0149] The preparation method of the membrane electrode of this comparative example includes the following steps:

[0150] (1) The dried cathode catalyst coating and the dried anode catalyst coating are uniformly treated in an environment with a temperature of 50 °C and a humidity of 70% for 5 days to obtain the first cathode catalyst coating and the first anode catalyst coating.

[0151] (2) The first cathode catalyst coating and the first anode catalyst coating obtained in step (1) are respectively placed on both sides of the proton exchange membrane and adhered, and then roll-to-roll transfer printing is carried out to obtain the membrane electrode of this example.

[0152] Among them, the proton exchange membrane and the process conditions of roll-to-roll transfer printing are the same as those in Example 1.

[0153] The membrane electrodes prepared in each example and comparative example are respectively adhered and assembled with the frame and the gas diffusion layer to obtain the membrane electrode assemblies corresponding to the membrane electrodes prepared in each example and comparative example (the active area is 283 cm 2 ), and the above membrane electrode assemblies are respectively placed on the fixture and the polarization curves (I-V curves, current-internal resistance curves) are tested under certain working conditions (80 °C, the excess coefficient ratios of hydrogen and air are 1.5 and 2.0 respectively, and the back pressures of hydrogen and air are both 100 KPa).

[0154] Figure 4 It is a comparative diagram of the polarization curves of the membrane electrodes prepared in Example 1 and Comparative Example 1. FromFigure 4 It can be seen that, compared with Comparative Example 1, the voltage of the membrane electrode obtained in Example 1 has increased, and the internal resistance has decreased significantly after stabilization, which proves the effectiveness of the humid heat and drying treatment solutions after humid heat in this application.

[0155] The single cells corresponding to the membrane electrodes prepared in each example or comparative example were assembled into fuel cells, and their current densities and internal resistances at 0.65 V were tested respectively. The test results are shown in Table 1.

[0156] Table 1 Performance test results of fuel cells corresponding to the membrane electrodes prepared in each example or comparative example

[0157]

[0158]

[0159] As can be seen from Table 1, the membrane electrodes prepared in each example of this application have higher current densities and lower internal resistances compared with the membrane electrodes prepared in each comparative example. Specifically:

[0160] Compared with Comparative Example 1, in Example 1, the performance of the membrane electrode has improved, and the performance has increased from 0.65 V @ 1.45 A / cm 2 to 0.65 V @ 1.65 A / cm 2 , and the internal resistance has been reduced to 0.27 ohm, further proving that preparing the membrane electrode by using the preparation method of the membrane electrode of this application can improve the fitting state of the proton membrane and the catalytic layer (it is generally considered that the internal resistance will decrease accordingly when the fitting degree is good), reduce the poisoning effect of alcohol on platinum, and improve the performance consistency.

[0161] By comparing Example 1 with Comparative Examples 2-3, it can be seen that in the absence of the humid heat treatment of this application, or without high-temperature drying after the humid heat treatment, the current density at 0.65 V of the obtained membrane electrode will decrease significantly, and the internal resistance will increase at the same time.

[0162] By comparing Example 2, Example 4, Example 3, Example 5 with Comparative Example 1, it can be seen that for the humid heat treatment process of this application, the higher the humidity is controlled and the longer the treatment time is, the current density at 0.65 V of the obtained membrane electrode will increase, and the internal resistance will decrease to a certain extent at the same time.

[0163] By comparing Example 1, Examples 6-7 with Comparative Example 3, it can be seen that after adding high-temperature drying after the humid heat in this application, the current density of the obtained membrane electrode at 0.65 V will increase to a certain extent, and the internal resistance will decrease to a certain extent;

[0164] By comparing Example 1, Example 8 with Comparative Example 1, it can be seen that for the transfer printing treatment system of this application, the current density of the obtained membrane electrode at 0.65 V will increase significantly, and the internal resistance will decrease at the same time.

[0165] Figure 5It is a comparative diagram of DSC curves obtained by differential scanning calorimetry for the second cathode catalyst coating in Example 1 and the cathode catalyst coating in Comparative Example 1. From Figure 5 It can be seen that a heat release peak appears in Comparative Example 1. Generally, it is considered that this peak is the heat generated by the reaction of adsorbed alcohol with platinum. The larger the area of the heat release peak, the higher the alcohol content in the coating. However, no heat release peak appears in the DSC curve of Example 1, indicating that the adsorbed alcohol has been completely removed.

[0166] Figure 6 It is a comparative diagram of thermogravimetric curves for the second cathode catalyst coating in Example 1 and the first cathode catalyst coating in Comparative Example 3. From Figure 6 It can be known that the water content of the coating in Example 1 is about 3.94%, while that of Comparative Example 3 without drying treatment is as high as 10.02%. If the water content of the coating is too high, it will affect the heat transfer during roll-to-roll transfer, the adhesion between the proton membrane and the catalyst layer, resulting in performance degradation and increased internal resistance.

[0167] In summary, the preparation method of the membrane electrode provided by the present application has a simple process and can significantly improve the performance of the membrane electrode.

[0168] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0169] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0170] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for preparing a membrane electrode, characterized in that: include: The dried anode catalyst coating and the dried cathode catalyst coating are subjected to wet heat treatment to obtain a first anode catalyst coating and a first cathode catalyst coating; The anode catalyst coating after the wet heat treatment and the cathode catalyst coating after the wet heat treatment are respectively subjected to a first drying and a second drying to obtain a second anode catalyst coating and a second cathode catalyst coating; The second anode catalyst coating, the proton exchange membrane and the second cathode catalyst coating are laminated and then roller-transferred to obtain the membrane electrode.

2. The preparation method according to claim 1, characterized in that: The temperature of the wet heat treatment is 20-80°C.

3. The preparation method according to claim 1, characterized in that: The humidity of the wet heat treatment is 40-100%.

4. The preparation method according to claim 1, characterized in that: The time of the wet heat treatment is 3-30 days.

5. The preparation method according to claim 1, characterized in that: The temperatures of the first drying and the second drying are both 50-150°C.

6. The preparation method according to claim 1, characterized in that: The first drying and the second drying are performed simultaneously; and / or, During the first drying process, the moving speed of the first anode catalyst coating is 0.1-2.0 m / min; and / or, During the second drying process, the moving speed of the first cathode catalyst coating is 0.1-2.0 m / min; and / or, The transfer roller printing is roll-to-roll transfer roller printing.

7. A membrane electrode preparation system, applied to the membrane electrode preparation method according to any one of claims 1 to 6, comprising a transfer roller printing mechanism, a cathode catalyst layer unwinding, an anode catalyst layer unwinding and a proton exchange membrane unwinding for providing the proton exchange membrane, characterized in that: The cathode catalyst layer unwinding is used to provide the first cathode catalyst coating, and the anode catalyst layer unwinding is used to provide the first anode catalyst coating; The membrane electrode preparation system also includes: an anode catalyst coating drying device, used for performing the first drying of the first anode catalyst coating unwound from the anode catalyst layer, and sending the obtained second anode catalyst coating to the roller transfer mechanism for the roller transfer; The cathode catalyst coating drying device is used to carry out the second drying of the first cathode catalyst coating unwound from the cathode catalyst layer, and to send the obtained second cathode catalyst coating to the roller transfer mechanism for the roller transfer.

8. The preparation system according to claim 7, characterized in that: The anode catalyst coating drying device is arranged between the anode catalyst layer unwinding and the transfer roller printing mechanism, and is located below or in the middle of the proton exchange membrane unwinding; and / or, The cathode catalyst coating drying device is arranged between the cathode catalyst layer unwinding device and the transfer roller printing mechanism, and is located above the proton exchange membrane unwinding device; and / or, The anode catalyst coating drying device and the cathode catalyst coating drying device are both drying devices comprising a plurality of feed rollers and a hot air circulation system.

9. A membrane electrode, characterized in that: The preparation is carried out by the preparation method according to any one of claims 1 to 6 or the preparation system according to any one of claims 7 or 8.

10. A fuel cell, characterized in that: Comprising the membrane electrode as claimed in claim 9.

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