CN116404173A - Membrane electrode and preparation method thereof - Google Patents
Membrane electrode and preparation method thereof Download PDFInfo
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- CN116404173A CN116404173A CN202310672633.6A CN202310672633A CN116404173A CN 116404173 A CN116404173 A CN 116404173A CN 202310672633 A CN202310672633 A CN 202310672633A CN 116404173 A CN116404173 A CN 116404173A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
- H01M4/8657—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/881—Electrolytic membranes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8825—Methods for deposition of the catalytic active composition
- H01M4/8828—Coating with slurry or ink
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M2004/8678—Inert electrodes with catalytic activity, e.g. for fuel cells characterised by the polarity
- H01M2004/8689—Positive electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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Abstract
A membrane electrode and a preparation method thereof belong to the technical field of fuel cells; the membrane electrode comprises a catalytic layer and a proton exchange membrane, the catalytic layer comprises a first catalytic layer and a second catalytic layer, the first catalytic layer is arranged on the surface of the proton exchange membrane, the second catalytic layer is arranged on the surface of the first catalytic layer far away from the proton exchange membrane, and the ionomer of the second catalytic layer comprises fibrous ionomer; by adopting a structure of two catalytic layers, the second catalytic layer containing fibrous ionomer is arranged on the outer layer, and the drainage of the catalytic layer is facilitated by utilizing the hydrophobic characteristic of the fibrous ionomer. While the second catalytic layer of fibrous ionomer is capable of enhancing the porosity and proton transport rate of the entire catalytic layer. The first catalytic layer which does not contain fibrous ionomer is arranged on the inner layer, the hydrophilicity of the first catalytic layer is better than that of the second catalytic layer, and therefore the whole catalytic layer and the proton exchange membrane have certain humidity under the low humidity condition, and the effect of improving the low humidity performance of the membrane electrode adopting the fibrous ionomer is achieved.
Description
Technical Field
The application relates to the technical field of fuel cells, in particular to a membrane electrode and a preparation method thereof.
Background
In order to improve proton transmission of the catalytic layer of the membrane electrode, the ionomer can be prepared into a fiber shape in an electrostatic spinning mode, and the continuous proton transmission path and the fiber-shaped structure of the ionomer improve the porosity and the proton transmission rate of the catalytic layer; but membrane electrodes employing fibrous ionomers perform less in low humidity conditions.
Disclosure of Invention
The present application provides a membrane electrode and a method of preparing the same, which can improve the low humidity performance of a membrane electrode using a fibrous ionomer.
In a first aspect, embodiments of the present application provide a membrane electrode, where the membrane electrode includes a catalytic layer and a proton exchange membrane, the catalytic layer includes a first catalytic layer and a second catalytic layer, the first catalytic layer is disposed on a surface of the proton exchange membrane, the second catalytic layer is disposed on a surface of the first catalytic layer away from the proton exchange membrane, and an ionomer of the second catalytic layer includes a fibrous ionomer.
In the technical scheme of the embodiment of the application, through adopting the structure of two-layer catalytic layer, locate the second catalytic layer that contains fibrous ionomer and be close to the one side of diffusion layer, utilize fibrous ionomer hydrophobic characteristic in order to do benefit to the drainage of catalytic layer. While the second catalytic layer of fibrous ionomer is capable of enhancing the porosity and proton transport rate of the entire catalytic layer. The conventional first catalytic layer which does not contain fibrous ionomer is arranged on one side close to the proton exchange membrane, the hydrophilicity of the first catalytic layer is better than that of the second catalytic layer, and therefore the whole catalytic layer and the proton exchange membrane have certain humidity under the low humidity condition, and the effect of improving the low humidity performance of the membrane electrode adopting the fibrous ionomer is achieved.
As an alternative embodiment, the fibrous ionomer has a fiber diameter of 100 to 800nm; or (b)
The fiber diameter of the fibrous ionomer is 100-300 nm.
In the implementation process, the smaller the fiber diameter of the fibrous ionomer, the denser the whole catalytic layer is, and the more unfavorable the drainage is, while the larger the fiber diameter of the fibrous ionomer, the smaller the specific surface area of the fibrous ionomer is, and the more unfavorable the mass transfer of the catalytic layer is. The fiber diameter of the fibrous ionomer is controlled to be 100-800 nm, so that the drainage performance and the mass transfer performance of the whole catalytic layer can be considered.
As an alternative embodiment, the contact angle of the second catalytic layer is greater than the contact angle of the first catalytic layer; and/or
The contact angle of the second catalytic layer is 130-140 degrees; and/or
The contact angle of the first catalytic layer is 120-130 degrees.
In the implementation process, the contact angle of the second catalytic layer is controlled to be larger than that of the first catalytic layer, so that the whole catalytic layer and the proton exchange membrane have certain humidity under the low-humidity condition on the premise of good drainage performance, and further the membrane electrode has good low-humidity performance.
As an alternative embodiment, the porosity of the second catalytic layer is greater than the porosity of the first catalytic layer; and/or
The porosity of the second catalytic layer is 0.6-0.8; and/or
The porosity of the first catalytic layer is 0.4-0.6.
In the implementation process, the porosity is positively correlated with the hydrophobicity to a certain extent, the porosity of the second catalytic layer is controlled to be larger than that of the first catalytic layer, so that the second catalytic layer has higher porosity and proton transmission rate, and meanwhile, the first catalytic layer has certain moisture retention, so that the whole catalytic layer and the proton exchange membrane have certain humidity under the low-humidity condition, and further have better performance.
As an alternative embodiment, the catalyst loading of the second catalytic layer is less than the catalyst loading of the first catalytic layer; and/or
The catalyst comprises at least one of a platinum carbon catalyst and a platinum alloy catalyst; and/or
The platinum carrying capacity of the second catalytic layer is 0.05-0.2 mg/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the And/or
The platinum carrying capacity of the first catalytic layer is 0.1-0.2 mg/cm 2 。
In the implementation process, the second catalytic layer has higher porosity and stronger proton transmission capacity, so that the corresponding resistance of substance transmission is lower, the same catalytic effect can be realized under the condition of lower catalyst consumption, and the reduction of the catalyst consumption is realized by controlling the catalyst loading of the second catalytic layer to be smaller than that of the first catalytic layer, thereby being beneficial to the control of cost.
As an alternative implementation mode, the thickness of the proton exchange membrane is 8-18 μm; and/or
The thickness of the first catalytic layer is 4-8 mu m; and/or
The thickness of the second catalytic layer is 1-4 μm.
In a second aspect, an embodiment of the present application provides a method for preparing a membrane electrode, where the method includes:
obtaining a first catalytic layer slurry;
obtaining a fibrous ionomer, and then preparing the fibrous ionomer into a second catalytic layer slurry;
and respectively attaching the first catalytic layer slurry and the second catalytic layer slurry to the proton exchange membrane to prepare a first catalytic layer and a second catalytic layer to obtain a membrane electrode, wherein the first catalytic layer is arranged on the surface of the proton exchange membrane, and the second catalytic layer is arranged on the surface of the first catalytic layer far away from the proton exchange membrane.
As an alternative embodiment, obtaining a fibrous ionomer comprises:
mixing an ionomer solution and a high molecular polymer in a solvent to obtain a mixed solution;
and carrying out electrostatic spinning on the mixed solution to obtain the fibrous ionomer.
As an alternative implementation mode, the molecular weight of the high molecular polymer is 50-200 kDa; and/or
The ionomer Ew in the ionomer solution is 800-1200 g/mol; and/or
The mass concentration of the high molecular polymer in the mixed solution is 0.5% -3%; and/or
The total mass concentration of the high molecular polymer and the ionomer in the mixed solution is 5% -25%.
In the implementation process, the molecular weight of the high molecular polymer is controlled to be 50-200 kDa, so that the solution in the subsequent electrostatic spinning process has proper viscosity, the resistance to stretching caused by an electric field is reduced, and the prepared fibrous ionomer has proper fiber diameter. The ionomer Ew in the ionomer solution is controlled to be 800-1200 g/mol, so that the second catalytic layer has proper hydrophilic and hydrophobic properties. The influence of the high polymer on the property of the ionomer can be reduced by controlling the mass concentration of the high polymer in the mixed solution to be 0.5% -3%. The second catalytic layer can be made to have proton transmission performance and oxygen transmission performance at the same time by controlling the total mass concentration of the high molecular polymer and the ionomer in the mixed solution to be 5% -25%.
As an optional implementation manner, the mass ratio of the catalyst in the second catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the second catalytic layer slurry is 0.5% -1.0; and/or
The mass ratio of the catalyst in the first catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the first catalytic layer slurry is 0.75% -1.5.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a membrane electrode according to an embodiment of the present disclosure;
FIG. 2 is a flow chart of a method provided by an embodiment of the present application;
FIG. 3 is a graph showing the results of performance testing of the membrane electrodes provided in examples 1 to 5 of the present application;
fig. 4 is a graph showing the results of the low-humidity performance test of the membrane electrode provided in example 1 and comparative examples 1 to 2 of the present application.
Icon: 1-proton exchange membrane; 2-a catalytic layer; 21-a first catalytic layer; 22-a second catalytic layer; a 3-diffusion layer; 4-anode catalytic layer.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
Unless specifically indicated otherwise, the various raw materials, reagents, instruments, equipment, and the like used in this application are commercially available or may be prepared by existing methods.
Various embodiments of the present application may exist in a range format; it should be understood that the description in a range format is merely for convenience and brevity and should not be interpreted as a rigid limitation on the scope of the application. Accordingly, the description of a range should be considered to have specifically disclosed all possible sub-ranges as well as single numerical values within that range. For example, it should be considered that a description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, wherever the range applies. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In this application, unless otherwise indicated, terms of orientation such as "upper" and "lower" are used specifically to refer to the orientation of the drawing in the figures. In addition, in the description of the present application, the terms "include", "comprise", "comprising" and the like mean "including but not limited to". Relational terms such as "first" and "second", and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Herein, "and/or" describing an association relationship of an association object means that there may be three relationships, for example, a and/or B, may mean: a alone, a and B together, and B alone. Wherein A, B may be singular or plural. Herein, "at least one" means one or more, and "a plurality" means two or more. "at least one", "at least one" or the like refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, "at least one (individual) of a, b, or c," or "at least one (individual) of a, b, and c," may each represent: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, wherein a, b, c may be single or multiple, respectively.
In order to improve proton transmission of the membrane electrode catalytic layer 2, the ionomer can be prepared into a fiber shape in an electrostatic spinning mode, and the continuous proton transmission path and the fiber-shaped structure of the ionomer improve the porosity and the proton transmission rate of the catalytic layer 2. The inventors found that: the catalytic layer 2 employing fibrous ionomers has a strong drainage capacity due to the combination of small average fiber diameter and high inter-fiber porosity. The membrane electrode using the catalytic layer 2 has low humidity performance due to the strong water-discharging ability of the catalytic layer 2.
The inventors have intended to provide a membrane electrode to improve its low-humidity performance by dividing the catalytic layer 2 into two layers, a first catalytic layer 21 adjacent to the proton exchange membrane 1 and a second catalytic layer 22 adjacent to the diffusion layer 3, respectively, the ionomer of the second catalytic layer 22 being a fibrous ionomer obtained by electrospinning. The fibrous ionomer itself has a certain hydrophobicity, the use of fibrous ionomer near the diffusion layer 3 facilitates drainage, while the first catalytic layer 21, which is near the proton exchange membrane 1 and does not contain fibrous ionomer, ensures that the low-humidity lower catalytic layer 2 and the proton exchange membrane 1 are not overdried. In addition, the second catalytic layer 22 has higher porosity and strong proton transport capacity, so that the substance transport resistance is low, and the platinum amount can be reduced.
As shown in fig. 1, the embodiment of the application provides a membrane electrode, the membrane electrode includes a catalytic layer 2 and a proton exchange membrane 1, the catalytic layer 2 includes a first catalytic layer 21 and a second catalytic layer 22, the first catalytic layer 21 is disposed on the surface of the proton exchange membrane 1, the second catalytic layer 22 is disposed on the surface of the first catalytic layer 21 far away from the proton exchange membrane 1, and an ionomer of the second catalytic layer 22 includes a fibrous ionomer.
The membrane electrode adopts a structure of two catalytic layers 2, and a second catalytic layer 22 containing fibrous ionomer is arranged on one side close to the diffusion layer 3, so that the drainage of the catalytic layers 2 is facilitated by utilizing the hydrophobic characteristic of the fibrous ionomer. While the second catalytic layer 22 of fibrous ionomer is able to promote porosity and proton transport rate throughout the catalytic layer 2. The conventional first catalytic layer 21 without fibrous ionomer is arranged on one side close to the proton exchange membrane 1, and the hydrophilicity of the first catalytic layer 21 is better than that of the second catalytic layer 22, so that the whole catalytic layer 2 and the proton exchange membrane 1 have certain humidity under the low humidity condition, and the effect of improving the low humidity performance of the membrane electrode adopting the fibrous ionomer is further realized.
In some embodiments, the fibrous ionomer has a fiber diameter of 100 to 800nm; preferably, the fibrous ionomer has a fiber diameter of 100 to 300nm. The smaller the fiber diameter of the fibrous ionomer, the denser the whole catalytic layer 2 will be, and the more unfavorable the drainage, while the larger the fiber diameter of the fibrous ionomer, the smaller the specific surface area of the fibrous ionomer will be, and the more unfavorable the mass transfer of the catalytic layer 2 will be. The water drainage performance and the mass transfer performance of the whole catalytic layer 2 can be considered by controlling the fiber diameter of the fibrous ionomer to be 100-800 nm.
For example, the fiber diameter of the fibrous ionomer may be 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300nm, 320 nm, 340 nm, 360 nm, 380 nm, 400nm, 420 nm, 440 nm, 460 nm, 480 nm, 500 nm, 520 nm, 540 nm, 560 nm, 580 nm, 600nm, 620 nm, 640 nm, 660 nm, 680 nm, 700 nm, 720 nm, 740 nm, 760 nm, 780 nm, 800nm, and the like, which may also be any value in the range of 100 to 800nm.
In some embodiments, the contact angle of the second catalytic layer 22 is greater than the contact angle of the first catalytic layer 21. The contact angle of the second catalytic layer 22 is controlled to be larger than that of the first catalytic layer 21, so that the whole catalytic layer 2 and the proton exchange membrane 1 have certain humidity under the low humidity condition on the premise of having good drainage performance, and further the membrane electrode has good low humidity performance.
Optionally, the contact angle of the second catalytic layer 22 is 130-140 °; the contact angle of the first catalytic layer 21 is 120-130 degrees. Illustratively, the contact angle of the second catalytic layer 22 may be 130 °, 131 °, 132 °, 133 °, 134 °, 135 °, 136 °, 137 °, 138 °, 139 °, 140 °, etc., which may also be any value within the range of 130-140 °; the contact angle of the first catalytic layer 21 may be 120 °, 121 °, 122 °, 123 °, 124 °, 125 °, 126 °, 127 °, 128 °, 129 °, 130 °, or the like, and may be any value within a range of 120 to 130 °.
In some embodiments, the porosity of the second catalytic layer 22 is greater than the porosity of the first catalytic layer 21. The porosity is positively correlated with the hydrophobicity to a certain extent, the porosity of the second catalytic layer 22 is controlled to be larger than that of the second catalytic layer 22, so that the second catalytic layer 22 has higher porosity and proton transmission rate, and meanwhile, the first catalytic layer 21 has certain moisture retention, so that the whole catalytic layer 2 and the proton exchange membrane 1 have certain humidity under the low-humidity condition, and further have better performance.
Optionally, the porosity of the second catalytic layer 22 is 0.6-0.8; the porosity of the first catalytic layer 21 is 0.4 to 0.6. Illustratively, the porosity of the second catalytic layer 22 may be 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, etc., which may also be any value within the range of 0.6-0.8; the porosity of the first catalytic layer 21 may be 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, etc., and may be any value within a range of 0.4 to 0.6.
In some embodiments, the catalyst loading of the second catalytic layer 22 is less than the catalyst loading of the first catalytic layer 21. The second catalytic layer 22 has higher porosity and stronger proton transmission capability, and the corresponding resistance of substance transmission is lower, so that the same catalytic effect can be realized under the condition of lower catalyst dosage, and the reduction of the catalyst dosage is realized by controlling the catalyst loading of the second catalytic layer 22 to be smaller than that of the first catalytic layer 21, thereby being beneficial to the control of cost.
In some embodiments, the catalyst comprises at least one of a platinum carbon catalyst and a platinum alloy catalyst, optionally with a platinum loading of 0.05 to 0.2mg/cm for the second catalytic layer 22 2 The method comprises the steps of carrying out a first treatment on the surface of the The platinum loading of the first catalytic layer 21 is 0.1-0.2 mg/cm 2 . Exemplary, the platinum loading of the second catalytic layer 22 may be 0.05mg/cm 2 、0.06 mg/cm 2 、0.07 mg/cm 2 、0.08 mg/cm 2 、0.09 mg/cm 2 、0.1 mg/cm 2 、0.11 mg/cm 2 、0.12 mg/cm 2 、0.13 mg/cm 2 、0.14 mg/cm 2 、0.15 mg/cm 2 、0.16 mg/cm 2 、0.17 mg/cm 2 、0.18 mg/cm 2 、0.19 mg/cm 2 And 0.2. 0.2mg/cm 2 And the like, which may be 0.05 to 0.2mg/cm 2 Any value within the range. The platinum loading of the first catalytic layer 21 may be 0.1mg/cm 2 、0.11 mg/cm 2 、0.12 mg/cm 2 、0.13 mg/cm 2 、0.14 mg/cm 2 、0.15 mg/cm 2 、0.16 mg/cm 2 、0.17 mg/cm 2 、0.18 mg/cm 2 、0.19 mg/cm 2 And 0.2. 0.2mg/cm 2 And the like, which may be 0.1 to 0.2mg/cm 2 Any value within the range.
In some embodiments, the proton exchange membrane 1 has a thickness of 8-18 μm; the thickness of the first catalytic layer 21 is 4-8 μm; the thickness of the second catalytic layer 22 is 1-4 μm.
Based on the same inventive concept, as shown in fig. 2, the embodiment of the application further provides a method for preparing a membrane electrode, which includes:
s1, obtaining first catalytic layer slurry;
specifically, in this embodiment, a certain amount of metal catalyst, ionomer solution, and water-alcohol are weighed and mixed uniformly by means of ultrasound, stirring, etc., to obtain a first catalytic layer slurry. Wherein the metal catalyst may be a platinum carbon catalyst or a platinum alloy catalyst. The mixing mode is stirring, ultrasonic, ball milling, sand milling, emulsifying shearing and the like
In some embodiments, the mass ratio of the catalyst in the first catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the first catalytic layer slurry is 0.75% -1.5. Illustratively, the mass ratio of the catalyst in the first catalytic layer slurry may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc., which may also be any value of 10% -60%; the mass ratio of carbon to ionomer of the catalyst in the first catalytic layer slurry may be 0.75, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, etc., which may also be any value in the range of 0.75 to 1.5.
S2, obtaining a fibrous ionomer, and preparing the fibrous ionomer into second catalytic layer slurry;
in some embodiments, obtaining the fibrous ionomer comprises: mixing an ionomer solution and a high molecular polymer in a solvent to obtain a mixed solution; and carrying out electrostatic spinning on the mixed solution to obtain the fibrous ionomer.
Specifically, in this embodiment, a certain amount of ionomer solution, high molecular polymer and alcohol are weighed in a beaker, and dispersed uniformly to obtain a mixed solution; and (3) regulating the spinning voltage, the flow rate, the nozzle-collecting plate spacing and the humidity of the electrostatic spinning equipment to carry out electrostatic spinning on the obtained mixed solution, and collecting the product (fibrous ionomer) on silicone paper or coated paper. Weighing a certain amount of fibrous ionomer obtained by electrostatic spinning, and uniformly mixing the fibrous ionomer with a metal catalyst and a hydroalcoholic solvent to obtain a second-layer catalyst layer slurry. Wherein the high molecular polymer can be selected from PEO, PVA, PAA, the solvent can be selected from methanol/water, ethanol/water, 2-propanol/water, 1-propanol/water, DMF, etc., and the dispersion mode is generally ultrasonic, stirring, etc., and the dispersion time is 2-8h. The electrostatic spinning parameters are controlled as follows: the ambient humidity may be 20-40% RH; the voltage may be 2-18 kV; the flow rate can be 0.1-1.2 mL/h; d spray head-collection plate = 2-8cm. The metal catalyst may be a platinum carbon catalyst or a platinum alloy catalyst. The mixing mode is generally stirring, ultrasonic, ball milling, sand milling, emulsifying shearing and the like.
It should be noted that the ionomer may not be added in the preparation process of the second catalytic layer slurry, and the ionomer may be added in addition. Similarly, the same diameter fibrous ionomer may be used, or a different diameter fibrous ionomer may be used.
Further, the molecular weight of the high molecular polymer is 50-200 kDa; the molecular weight of the high molecular polymer may be, for example, 50 KDa, 60 KDa, 70 KDa, 80 KDa, 90KDa, 100 KDa, 110 KDa, 120 KDa, 130 KDa, 140 KDa, 150 KDa, 160 KDa, 170 KDa, 180 KDa, 190 KDa, 200KDa, etc., and may also be any value within the range of 50 to 200KDa, and by controlling the molecular weight of the high molecular polymer to be 50 to 200KDa, the solution in the subsequent electrospinning process has a relatively suitable viscosity, and the resistance to stretching caused by an electric field is reduced, so that the prepared fibrous ionomer has a relatively suitable fiber diameter. The ionomer Ew in the ionomer solution is 800 to 1200g/mol, and exemplary ionomer Ew in the ionomer solution may be 800 g/mol, 900 g/mol, 1000 g/mol, 1100 g/mol, and 1200g/mol; the ionomer Ew in the ionomer solution is controlled to be 800-1200 g/mol, so that the second catalytic layer 22 has more proper hydrophilic-hydrophobic performance. The mass concentration of the high molecular polymer in the mixed solution is 0.5% -3%; for example, the mass concentration of the polymer in the mixed solution may be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc., and it may also be any value within the range of 0.5% -3%, and the influence of the polymer on the ionomer property can be reduced by controlling the mass concentration of the polymer in the mixed solution to be 0.5% -3%. The total mass concentration of the high molecular polymer and the ionomer in the mixed solution is 5% -25%, and the total mass concentration of the high molecular polymer and the ionomer in the mixed solution can be 5%, 10%, 15%, 20%, 25% and the like, and can be any value in the range of 5% -25%; the second catalytic layer 22 can be made to have both proton transport performance and oxygen transport performance by controlling the total mass concentration of the high molecular polymer and the ionomer in the mixed solution to 5% -25%.
In some embodiments, the mass ratio of the catalyst in the second catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the second catalytic layer slurry is 0.5-1.0. Illustratively, the mass ratio of the catalyst in the second catalytic layer slurry may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc., which may also be any value of 10% -60%; the mass ratio of the carbon and the ionomer of the catalyst in the second catalytic layer slurry may be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, etc., and may be any value within the range of 0.5 to 1.0.
S3, respectively attaching the first catalytic layer slurry and the second catalytic layer slurry to the proton exchange membrane 1 to prepare a first catalytic layer 21 and a second catalytic layer 22, thereby obtaining a membrane electrode, wherein the first catalytic layer 21 is arranged on the surface of the proton exchange membrane 1, and the second catalytic layer 22 is arranged on the surface of the first catalytic layer 21 far away from the proton exchange membrane 1.
The first catalytic layer slurry and the second catalytic layer slurry may be directly coated on the proton exchange membrane 1 or indirectly attached to the proton exchange membrane 1 by transfer printing. The following will specifically describe the manner in which the proton exchange membrane 1 is directly coated.
Specifically, in this embodiment, the first catalytic layer slurry is coated on the proton exchange membrane 1 to form the first catalytic layer 21, then the second catalytic layer slurry is coated on the first catalytic layer 21 to form the second catalytic layer 22, and then the preparation of the diffusion layer 3 and the like is performed to obtain the membrane electrode.
It will be appreciated by those skilled in the art that the manner of transfer to attach the first catalytic layer 21 and the second catalytic layer 22 to the proton exchange membrane is the opposite of directly coating the proton exchange membrane 1, specifically, the second catalytic layer 22 is attached to the transfer substrate layer, then the first catalytic layer 21 is attached to the second catalytic layer 22, and finally transferred to the proton exchange membrane 1.
The present application is further illustrated below in conjunction with specific examples. It should be understood that these examples are illustrative only of the present application and are not intended to limit the scope of the present application. The experimental procedures, which are not specified in the following examples, are generally determined according to national standards. If the corresponding national standard does not exist, the method is carried out according to the general international standard, the conventional condition or the condition recommended by the manufacturer.
Example 1
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 16 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 200nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain second catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain a first catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (4) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (3) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the coating Pt loading is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Example 2
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 12 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 400nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain second catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain a first catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (4) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (3) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the coating Pt loading is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Example 3
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 8 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 600nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain second catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain a first catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (4) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (3) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the coating Pt loading is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Example 4
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 20 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 50nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain second catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain a first catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (4) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (3) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the coating Pt loading is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Example 5
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 6 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 900nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain second catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain a first catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (4) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (3) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the coating Pt loading is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Comparative example 1
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 16 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 200nm;
(3) Weighing 3g of 60wt% Pt/C cathode catalyst and 1.2g of Nafion ionomer fiber prepared in the step (2), adding 40g of water and 120g of isopropanol, mixing, and shearing and dispersing to obtain cathode catalyst slurry;
(4) Spraying the cathode catalyst slurry in the step (3) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.4mg/cm 2 Measuring a contact angle after the cathode catalyst layer is dried;
(5) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(6) And (3) coating the anode slurry in the step (5) on the proton exchange membrane in the step (4) to prepare an anode catalytic layer, wherein the coating Pt load is as follows: 0.05mg/cm 2 ；
(7) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (6) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
Comparative example 2
A method for preparing a membrane electrode, the method comprising:
(1) Preparing an electrostatic spinning solution: weighing 20g of Nafion D2020, 2g of PVP 90kDa and 10g of DMF in a beaker, and magnetically stirring at 60 ℃ for 2 hours to uniformly disperse the materials;
(2) The environmental humidity is 20% RH, the room temperature, the electrostatic spinning voltage is 16 kV, the distance between a spinning needle head and a collecting plate is 6cm, the spinning speed is 0.4mL/min, and the product is collected on silicone paper, so that the diameter of the ionomer fiber is about 200nm;
(3) Weighing 1.5g of 60wt% Pt/C cathode catalyst and 0.6g of Nafion ionomer fiber prepared in the step (2), adding 20g of water and 60g of isopropanol, mixing, and shearing and dispersing to obtain a first catalytic layer slurry;
(4) 1.5g of 60wt% Pt/C cathode catalyst and 3g of Nafion D2020 ionomer solution are weighed, 20g of water and 60g of isopropanol are added and mixed, and then shearing and dispersing are carried out to obtain second catalytic layer slurry;
(5) Spraying the slurry of the first catalytic layer in the step (3) on an 8um proton exchange membrane, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the first catalytic layer 21 is dried;
(6) Spraying the second catalytic layer slurry in the step (4) on the first catalytic layer, wherein the Pt loading is as follows: 0.2mg/cm 2 Measuring the contact angle after the second catalytic layer 22 is dried;
(7) Weighing 10g of anode Pt/C catalyst, 20g of Nafion solution, 100g of water and 75g of ethanol, mixing and performing ultrasonic dispersion to obtain anode slurry;
(8) Coating the anode slurry in the step (7) on the proton exchange membrane in the step (6) to prepare an anode catalytic layer, wherein the Pt coating load is as follows: 0.05mg/cm 2 ；
(9) And (3) packaging the catalytic layer and proton exchange membrane combination obtained in the step (8) with the 250um gas diffusion layer 3 to obtain the membrane electrode.
The performance test of the membrane electrodes provided in examples 1 to 5 and comparative examples 1 to 2, which includes the evaluation of hydrophilicity of the catalytic layer 2, the evaluation of low-humidity performance of the membrane electrode, and the evaluation of performance of the membrane electrode, is specifically as follows:
catalyst layer hydrophilicity and hydrophobicity evaluation: the larger the contact angle, the more hydrophobic the catalyst layer, the smaller the contact angle, the more hydrophilic the catalyst layer, as assessed by contact angle testing. In preparing the dual catalyst layer, the contact angles of the first catalyst layer and the second catalyst layer were tested, respectively.
Membrane electrode low humidity performance evaluation: hydrogen is introduced into the anode (metering ratio is 1.4), air is introduced into the cathode (metering ratio is 2.1), anode pressure is 140kPa, cathode pressure is 150kPa, anode 40% RH, cathode dry gas and stacking temperature is 85 ℃, and membrane electrode area is 50cm 2 The current 100A was maintained for 1h with three sweeps until the output voltage no longer increased and activation was complete. The VI curve was tested.
Membrane electrode performance evaluation: hydrogen is introduced into the anode (metering ratio 1.4), air is introduced into the cathode (metering ratio 2.1), anode pressure is 140kPa, cathode pressure is 150kPa, RH is 100%, stack temperature is 80 ℃, and membrane electrode area is 50cm 2 The current 100A was maintained for 1h with three sweeps until the output voltage no longer increased and activation was complete. And testing a VI curve, testing constant current, and recording the VI curve and open circuit voltage, wherein the maximum current is zero.
The following table and fig. 3 and 4 show the detection results:
as can be seen from a comparison of the data of examples 1 to 5, the first catalytic layer 21 is a conventional ionomer and the second catalytic layer 22 is a fibrous ionomer, and as a comparison of contact angles, the first catalytic layer is more hydrophilic, the second catalytic layer is more hydrophobic, and the degree of hydrophobicity increases as the diameter of the fibrous ionomer increases.
FIG. 3 is a graph showing the results of the performance test of the membrane electrode provided in examples 1 to 5, wherein the diameter of the fibrous ionomer is 100-800 nm, and the diameter of the fibrous ionomer is 200nm, which is a better choice, as the diameter of the fibrous ionomer is increased by 100% RH, and the performance of the membrane electrode is shown to be better and worse. The inventors analyzed that the cause may be: the smaller the diameter of the fibrous ionomer may result in a catalyst layer that is too dense for drainage, while the larger the diameter of the fibrous ionomer may result in a catalyst layer 2 that is not conducive to mass transfer.
Fig. 4 is a graph showing the results of the low-humidity performance test of the membrane electrodes provided in example 1 and comparative examples 1 to 2, as can be obtained from the graph, the performance size was: example 1 > comparative example 2, the membrane electrode of the double-layer catalytic layer 2 in which the second catalytic layer 22 (outer layer) contains a fibrous ionomer and the first catalytic layer 21 (inner side) contains a conventional ionomer was excellent at low humidity, and the inventors analyzed that the reason thereof might be: while the inner conventional ionomer has some water retention capacity, the outer fibrous ionomer facilitates gas transport, in contrast to the catalyst layer of comparative example 1, which is all fibrous ionomer, which is too hydrophobic, resulting in low moisture performance. In comparative example 2, the inner catalyst layer was a fibrous ionomer, so that the inner layer was well drained, resulting in a drier proton exchange membrane 1 near the catalyst layer, which was detrimental to the low humidity performance of the membrane electrode.
The foregoing is merely a specific embodiment of the present application and is not intended to limit the application, and various modifications and variations may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (10)
1. The membrane electrode is characterized by comprising a catalytic layer and a proton exchange membrane, wherein the catalytic layer comprises a first catalytic layer and a second catalytic layer, the first catalytic layer is arranged on the surface of the proton exchange membrane, the second catalytic layer is arranged on the surface, far away from the proton exchange membrane, of the first catalytic layer, and the ionomer of the second catalytic layer comprises a fibrous ionomer.
2. The membrane electrode of claim 1, wherein the fibrous ionomer has a fiber diameter of 100-800 nm.
3. The membrane electrode of claim 1, wherein the contact angle of the second catalytic layer is greater than the contact angle of the first catalytic layer; and/or
The contact angle of the second catalytic layer is 130-140 degrees; and/or
The contact angle of the first catalytic layer is 120-130 degrees.
4. The membrane electrode of claim 1, wherein the second catalytic layer has a porosity greater than the first catalytic layer; and/or
The porosity of the second catalytic layer is 0.6-0.8; and/or
The porosity of the first catalytic layer is 0.4-0.6.
5. The membrane electrode of claim 1, wherein the catalyst loading of the second catalytic layer is less than the catalyst loading of the first catalytic layer; and/or
The catalyst comprises at least one of a platinum carbon catalyst and a platinum alloy catalyst; and/or
The platinum carrying capacity of the second catalytic layer is 0.05-0.2 mg/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the And/or
The platinum carrying capacity of the first catalytic layer is 0.1-0.2 mg/cm 2 。
6. The membrane electrode according to claim 1, wherein the proton exchange membrane has a thickness of 8-18 μm; and/or
The thickness of the first catalytic layer is 4-8 mu m; and/or
The thickness of the second catalytic layer is 1-4 mu m.
7. A method of preparing a membrane electrode, the method comprising:
obtaining a first catalytic layer slurry;
obtaining a fibrous ionomer, and then preparing the fibrous ionomer into a second catalytic layer slurry;
and respectively attaching the first catalytic layer slurry and the second catalytic layer slurry to a proton exchange membrane to prepare a first catalytic layer and a second catalytic layer to obtain a membrane electrode, wherein the first catalytic layer is arranged on the surface of the proton exchange membrane, and the second catalytic layer is arranged on the surface, far away from the proton exchange membrane, of the first catalytic layer.
8. The method of preparing a membrane electrode according to claim 7, wherein the obtaining a fibrous ionomer comprises:
mixing an ionomer solution and a high molecular polymer in a solvent to obtain a mixed solution;
and carrying out electrostatic spinning on the mixed solution to obtain the fibrous ionomer.
9. The method for preparing a membrane electrode according to claim 8, wherein the molecular weight of the high molecular polymer is 50-200 kda; and/or
The ionomer Ew in the ionomer solution is 800-1200 g/mol; and/or
The mass concentration of the high molecular polymer in the mixed solution is 0.5% -3%; and/or
The total mass concentration of the high molecular polymer and the ionomer in the mixed solution is 5% -25%.
10. The method for preparing a membrane electrode according to claim 7, wherein the mass ratio of the catalyst in the second catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the second catalytic layer slurry is 0.5% -1.0; and/or
The mass ratio of the catalyst in the first catalytic layer slurry is 10% -60%, and the mass ratio of the carbon and the ionomer in the catalyst in the first catalytic layer slurry is 0.75% -1.5.
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| CN103413947A (en) * | 2013-08-27 | 2013-11-27 | 武汉理工大学 | Fuel cell ordered porous nano-fiber single electrode, membrane electrode and preparation method |
| JP2019083181A (en) * | 2017-10-30 | 2019-05-30 | 凸版印刷株式会社 | Membrane electrode assembly and solid polymer fuel cell |
| CN109860630A (en) * | 2019-01-07 | 2019-06-07 | 北京卡达克数据有限公司 | Preparation method, the Catalytic Layer of nano-fiber catalyst slurry prepare and the preparation method of CCM film |
| US20190280307A1 (en) * | 2018-03-08 | 2019-09-12 | GM Global Technology Operations LLC | Composite electrode layer for polymer electrolyte fuel cell |
| CN114420948A (en) * | 2022-01-24 | 2022-04-29 | 一汽解放汽车有限公司 | Cathode catalyst layer and preparation method and application thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103413947A (en) * | 2013-08-27 | 2013-11-27 | 武汉理工大学 | Fuel cell ordered porous nano-fiber single electrode, membrane electrode and preparation method |
| JP2019083181A (en) * | 2017-10-30 | 2019-05-30 | 凸版印刷株式会社 | Membrane electrode assembly and solid polymer fuel cell |
| US20190280307A1 (en) * | 2018-03-08 | 2019-09-12 | GM Global Technology Operations LLC | Composite electrode layer for polymer electrolyte fuel cell |
| CN109860630A (en) * | 2019-01-07 | 2019-06-07 | 北京卡达克数据有限公司 | Preparation method, the Catalytic Layer of nano-fiber catalyst slurry prepare and the preparation method of CCM film |
| CN114420948A (en) * | 2022-01-24 | 2022-04-29 | 一汽解放汽车有限公司 | Cathode catalyst layer and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117877973A (en) * | 2024-03-08 | 2024-04-12 | 合肥晶合集成电路股份有限公司 | Method for manufacturing semiconductor structure |
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