CN117438596A - Preparation method of gradient catalytic layer membrane electrode - Google Patents
Preparation method of gradient catalytic layer membrane electrode Download PDFInfo
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- 239000012528 membrane Substances 0.000 title claims abstract description 95
- 230000003197 catalytic effect Effects 0.000 title claims abstract description 68
- 238000002360 preparation method Methods 0.000 title claims abstract description 46
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 188
- 239000003054 catalyst Substances 0.000 claims abstract description 165
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 50
- UQSQSQZYBQSBJZ-UHFFFAOYSA-N fluorosulfonic acid Chemical compound OS(F)(=O)=O UQSQSQZYBQSBJZ-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 43
- 238000011068 loading method Methods 0.000 claims abstract description 28
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 25
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 25
- 238000005507 spraying Methods 0.000 claims abstract description 25
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 20
- 239000010439 graphite Substances 0.000 claims abstract description 20
- 238000009792 diffusion process Methods 0.000 claims abstract description 17
- 238000004513 sizing Methods 0.000 claims abstract description 4
- 239000012046 mixed solvent Substances 0.000 claims description 90
- 239000000203 mixture Substances 0.000 claims description 72
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 60
- 238000003756 stirring Methods 0.000 claims description 54
- 239000002002 slurry Substances 0.000 claims description 51
- 239000011248 coating agent Substances 0.000 claims description 40
- 238000000576 coating method Methods 0.000 claims description 40
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 31
- 238000010008 shearing Methods 0.000 claims description 30
- 238000009210 therapy by ultrasound Methods 0.000 claims description 30
- 229910021642 ultra pure water Inorganic materials 0.000 claims description 30
- 239000012498 ultrapure water Substances 0.000 claims description 30
- 238000002156 mixing Methods 0.000 claims description 24
- 238000000034 method Methods 0.000 claims description 14
- 239000004890 Hydrophobing Agent Substances 0.000 claims description 11
- 238000005342 ion exchange Methods 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 17
- 239000001301 oxygen Substances 0.000 abstract description 17
- 229910052760 oxygen Inorganic materials 0.000 abstract description 17
- 239000002134 carbon nanofiber Substances 0.000 abstract description 15
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 15
- 239000007789 gas Substances 0.000 abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 8
- 239000007788 liquid Substances 0.000 abstract description 6
- 238000006722 reduction reaction Methods 0.000 abstract description 6
- 239000000243 solution Substances 0.000 description 39
- 239000006185 dispersion Substances 0.000 description 18
- 239000006255 coating slurry Substances 0.000 description 12
- 239000011259 mixed solution Substances 0.000 description 12
- 239000007921 spray Substances 0.000 description 12
- 238000012360 testing method Methods 0.000 description 12
- 239000006256 anode slurry Substances 0.000 description 10
- 238000013461 design Methods 0.000 description 9
- 238000005087 graphitization Methods 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 229920000554 ionomer Polymers 0.000 description 8
- 230000009286 beneficial effect Effects 0.000 description 6
- 239000006257 cathode slurry Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 238000009826 distribution Methods 0.000 description 6
- 230000010287 polarization Effects 0.000 description 6
- 230000002209 hydrophobic effect Effects 0.000 description 5
- 238000004806 packaging method and process Methods 0.000 description 5
- 229920000728 polyester Polymers 0.000 description 5
- 239000011347 resin Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 238000004321 preservation Methods 0.000 description 4
- 150000003460 sulfonic acids Chemical class 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 230000004913 activation Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 238000000157 electrochemical-induced impedance spectroscopy Methods 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000003273 ketjen black Substances 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 206010013496 Disturbance in attention Diseases 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 235000019441 ethanol Nutrition 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000007770 graphite material Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001453 impedance spectrum Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000001132 ultrasonic dispersion Methods 0.000 description 1
Classifications
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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
-
- 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
-
- 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]
-
- 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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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Inert Electrodes (AREA)
- Catalysts (AREA)
Abstract
The invention discloses a preparation method of a gradient catalytic layer membrane electrode, which comprises the following steps: step S1: preparing four parts of catalyst sizing agents which are D1, D2, D3 and D4 respectively; step S2: respectively spraying D1, D2 and D3 on one side of the proton exchange membrane in sequence to form a gradient cathode catalytic layer, and defining the side as a cathode; step S3: spraying D4 to the other side of the proton exchange membrane to form an anode catalytic layer; step S4: and (3) attaching gas diffusion layers to the proton exchange membrane with the two sides being sprayed to package the proton exchange membrane to prepare the membrane electrode. The present invention gradually reduces the platinum loading in the direction from the "first layer" to the third layer "to increase the rate of the oxygen reduction reaction. The perfluorosulfonic acid content is gradually reduced to increase proton conductivity. The carbon content of the graphite is gradually reduced to increase the discharge rate of the liquid water. Meanwhile, the invention increases the content of the carbon nano-fiber step by step so as to improve the diffusion rate of oxygen.
Description
Technical Field
The invention relates to the technical field of fuel cells, in particular to a preparation method of a gradient catalytic layer membrane electrode.
Background
The hydrogen energy is taken as a new clean, efficient and sustainable energy source, is regarded as the next generation energy source with the highest potential, has the advantages of high efficiency, cleanliness, low working temperature, high energy density and the like when being taken as an ideal mode of the hydrogen energy in the proton exchange membrane fuel cell, is an ideal clean energy source, and plays an important role because the membrane electrode is a key part for determining the performance of the fuel cell.
The existing gradient catalytic layer technology mainly comprises the following steps: 1. according to the concentration difference of the air inlet and the air outlet, the catalyst is realized by controlling the gradient of the catalyst loading, and patent CN103367757 discloses a catalyst with three-level gradient distribution, wherein the loading of a catalytic layer is gradually increased along the width direction from an inlet to an outlet. 2. The gradient of the monolithic membrane electrode is realized by controlling the EW value of the ionomer, and in the patent CN113991126A, the gradient catalytic layer is formed by designing the method that the EW value of the cathode gradually decreases along the direction from the proton membrane to the carbon paper, so that the performance of the membrane electrode is improved to a certain extent. 3. The preparation of the gradient catalytic layer is achieved by adjusting the proportions of the different dispersants, as mentioned in patent CN111463442a by controlling the proportions of alcohol and water in the slurry of the three catalytic layers.
The gradient catalytic layers related to the above patents can improve the performance of the membrane electrode to a certain extent, but the gradient catalytic layers designed by the above patents do not comprehensively consider the problems of optimizing the core reaction area of the cathode catalytic layer, oxygen transmission and liquid water removal.
Disclosure of Invention
The invention aims to provide a preparation method of a gradient catalytic layer membrane electrode
The aim of the invention can be achieved by the following technical scheme:
a preparation method of a gradient catalytic layer membrane electrode comprises the following steps:
step S1: preparing four parts of catalyst sizing agents which are D1, D2, D3 and D4 respectively;
step S2: respectively spraying D1, D2 and D3 on one side of the proton exchange membrane in sequence to form a gradient cathode catalytic layer, and defining the side as a cathode;
step S3: spraying D4 to the other side of the proton exchange membrane to form an anode catalytic layer;
step S4: and (3) attaching gas diffusion layers to the proton exchange membrane with the two sides being sprayed to package the proton exchange membrane to prepare the membrane electrode.
As a further scheme of the invention: the preparation process of the catalyst slurry D1 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 9.85g of 5% by mass of perfluorosulfonic acid solution, 0.0447g of hydrophobing agent and 0.0149g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D1.
As a further scheme of the invention: the preparation process of the catalyst slurry D2 comprises the following steps:
1g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 7.7778 g of 5% perfluorosulfonic acid solution, 0.0278 g of hydrophobing agent and 0.0278 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D2.
As a further scheme of the invention: the preparation process of the catalyst slurry D3 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 50% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution, 0.0130 g of hydrophobing agent and 0.0390 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D3.
As a further scheme of the invention: the preparation process of the catalyst slurry D4 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution by mass fraction, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D4.
As a further scheme of the invention: the Pt/C catalyst has a platinum content of 50-70%.
As a further scheme of the invention: the ion exchange equivalent of the perfluorosulfonic acid solution was 790 g/mol.
As a further scheme of the invention: the platinum loading in the anode catalytic layer is 0.01mg/cm2; the total platinum loading in the cathode catalytic layer was 0.4mg/cm2.
As a further scheme of the invention: the platinum loading ratio of the cathode first coating, the cathode second coating and the cathode third coating was 4:2.5:1.
as a further scheme of the invention: the catalyst Pt content of the cathode first coating, the cathode second coating, and the cathode third coating was 70%, 60%, and 50%, respectively.
As a further scheme of the invention: the ionomer mass fractions of the cathode first coating, cathode second coating, and cathode third coating were 32%, 27%, and 22%, respectively.
As a further scheme of the invention: the hydrophobizing agent is graphite carbon, and the mass fractions of the graphite carbon of the cathode first coating, the cathode second coating and the cathode third coating are 3%, 2% and 1% respectively.
As a further scheme of the invention: the pore-forming agent is carbon nanofiber, and the mass fraction of the carbon nanofiber of the cathode first coating, the cathode second coating and the cathode third coating is 1%, 2% and 3% respectively.
The invention has the beneficial effects that:
the cathode catalytic layer has a core reaction zone where most of the oxygen reduction reaction and reaction product formation occurs. In the oxygen reduction reaction, protons are transported across the proton exchange membrane from the anode to the cathode catalytic layer through electrolyte channels, and oxygen diffuses from the gas diffusion layer to the cathode catalytic layer through gas channels. Therefore, in the cathode catalytic layer, the proton concentration tends to decrease and the oxygen concentration tends to increase from the "side close to the proton exchange membrane" to the "side far from the proton exchange membrane".
The present invention gradually reduces the platinum loading in the direction from the "first layer to the third layer" to optimize the location of the core reaction zone. The perfluorosulfonic acid content is gradually reduced to optimize the proton conductivity of the core reaction zone. The graphitic carbon content is gradually reduced to enhance the discharge rate of product water from the core reaction zone. Meanwhile, the invention increases the content of the carbon nano-fiber step by step so as to enhance the diffusion rate of oxygen to the core reaction zone.
First, in order to realize the gradient distribution of platinum loading of the cathode catalytic layer, the position of the core reaction zone is optimized, and meanwhile, the influence of the excessive thickness of each gradient catalytic layer of the cathode on oxygen diffusion is avoided.
Second, to optimize proton conductivity in the core reaction zone, the ionomer comprises 32%, 27% and 22% of each coating by mass in the direction from "first layer to third layer" according to the present invention.
Thirdly, in order to realize the hydrophobic gradient distribution of the cathode catalytic layer and simultaneously enhance the conductivity and durability of the cathode catalytic layer, the hydrophobic agent adopted by the invention is a graphite carbon material subjected to high graphitization treatment.
Fourth, in order to realize gradient distribution of porosity of the cathode catalytic layer and simultaneously to strengthen conductivity and durability of the cathode catalytic layer, the pore-forming agent adopted by the invention is a carbon nanofiber material with high conductivity and high stability.
The performance of the fuel cell in the whole working range is greatly improved, and the technical problems of catalyst utilization rate, proton conductivity, liquid water discharge, oxygen diffusion and the like in the prior art are solved.
Drawings
The invention is further described below with reference to the accompanying drawings.
FIG. 1 is a schematic flow chart of the preparation method of the present invention;
fig. 2 is a schematic structural view of the membrane electrode of the present invention.
In the figure:
1-an anode catalytic layer;
2-proton exchange membrane;
3-a cathode first coating;
4-a cathode secondary coating;
5-cathode third coating.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-2, the present invention is a method for preparing a gradient catalytic layer membrane electrode. The gradient catalytic layer membrane electrode comprises an anode catalytic layer, a proton exchange membrane and a cathode catalytic layer, wherein the cathode catalytic layer is subjected to three-layer gradient design according to the characteristics of distribution of each substance and slow oxygen reduction reaction kinetics. The side near the proton exchange membrane (denoted as the first layer) increases the platinum loading and ionomer content to increase the oxygen reduction reaction rate and ionic conductivity, while adding a hydrophobic agent to drain liquid water faster. A pore former is added to the side remote from the proton exchange membrane (denoted as the third layer) to increase the oxygen diffusion rate. The middle side belongs to a transition layer (marked as a second layer) and cooperates with the first layer and the third layer to form a platinum loading gradient, an ionomer content gradient, a hydrophobicity gradient and a porosity gradient.
The gradient design membrane electrode realizes gradient distribution of platinum loading capacity, ionomer content, hydrophobicity and porosity by regulating and controlling slurry components of the cathode catalytic layer, and particularly, the catalytic layer is prepared by a spraying mode. The method comprises the following steps:
step S1: preparing four parts of catalyst sizing agents which are D1, D2, D3 and D4 respectively;
step S2: respectively spraying D1, D2 and D3 on one side of the proton exchange membrane in sequence to form a gradient cathode catalytic layer, and defining the side as a cathode;
step S3: spraying D4 to the other side of the proton exchange membrane to form an anode catalytic layer;
step S4: and (3) attaching gas diffusion layers to the proton exchange membrane with the two sides being sprayed to package the proton exchange membrane to prepare the membrane electrode.
In the present invention, the preparation process of the catalyst slurry D1 includes:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 9.85g of 5% by mass of perfluorosulfonic acid solution, 0.0447g of hydrophobing agent and 0.0149g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D1.
In the present invention, the preparation process of the catalyst slurry D2 includes:
1g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 7.7778 g of 5% perfluorosulfonic acid solution, 0.0278 g of hydrophobing agent and 0.0278 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D2.
In the present invention, the preparation process of the catalyst slurry D3 includes:
1g of a Pt/C catalyst with the Pt content of 50% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution, 0.0130 g of hydrophobing agent and 0.0390 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D3.
In the present invention, the preparation process of the catalyst slurry D4 includes:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution by mass fraction, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D4.
In the present invention, the Pt/C catalyst has a platinum content of 50-70%
Further, the ionomer in the catalyst layer slurry is a perfluorosulfonic acid resin having an ion exchange equivalent of 790 g/mol.
Further, the GDL is any one of JNTG21-A6L, JNTG 21-A6H.
Further, the platinum loading in the anode catalytic layer was 0.1mg/cm2.
Further, the total platinum loading in the cathode catalytic layer was 0.4mg/cm2.
Further, the platinum loading ratio of the cathode first coating, the cathode second coating, and the cathode third coating was 4:2.5:1.
further, the mass fraction of the perfluorosulfonic acid of the cathode catalytic layer is 22% -32%. [ this is the gradient range ]
Further, the graphite carbon is obtained by heat treatment of Ketjen black carbon powder in a graphitizing furnace.
Further, the thickness of the proton exchange membrane is 18um.
Further, the spray drying temperature is 110 ℃, and the slurry flow is 6m l/min.
Further, the ultrasonic dispersion temperature of the slurry is less than or equal to 15 ℃.
The catalyst Pt content of the cathode first coating, the cathode second coating, and the cathode third coating was 70%, 60%, and 50%, respectively.
Further, the ionomer mass fractions of the cathode first coating, the cathode second coating, and the cathode third coating were 32%, 27%, and 22%, respectively.
Further, the hydrophobizing agent is graphite carbon, and the mass fractions of the graphite carbon of the cathode first coating, the cathode second coating and the cathode third coating are 3%, 2% and 1%, respectively.
Further, the pore-forming agent is carbon nanofiber, and the mass fractions of the carbon nanofiber of the cathode first coating, the cathode second coating and the cathode third coating are 1%, 2% and 3% respectively.
Example 1
Preparation of graphite carbon hydrophobing agent
10 g of Ketjen black carbon powder of EC600JD model was weighed and charged into a graphitization furnace. Ensures that the carbon powder is placed in a way that does not obstruct the circulation of the atmosphere. The furnace atmosphere was replaced three times with 99.999% high purity argon. The rate of temperature rise was set at 5 degrees celsius/min. The graphitization treatment temperature was set at 2700 degrees celsius. And (3) starting to count after the graphitization heat preservation time reaches 2700 ℃, wherein the heat preservation time is set to 8 hours. After the graphitization step is completed, the control procedure naturally cools the furnace temperature to room temperature. Taking out the graphite carbon for standby.
Preparation of cathode first coating slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 9.8500 g of a 5% by mass perfluorosulfonic acid solution, 0.0447g of graphitic carbon, and 0.0149g of carbon nanofibers were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D1.
Preparation of cathode second coating slurry
1.0000 g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 7.7778 g of a 5% by mass perfluorosulfonic acid solution, 0.0278 g of graphitic carbon, and 0.0278 g of carbon nanofibers were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D2.
Preparation of cathode third coating slurry
1.0000 g of Pt/C catalyst with 50% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 5.9740 g of a 5% by mass perfluorosulfonic acid solution, 0.0130 g of graphitic carbon, and 0.0390 g of carbon nanofibers were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D3.
Preparation of anode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D4.
Membrane electrode preparation
The cathode slurries configured as described above were placed in three spray injectors, labeled D1, D2, D3, and D1, D2, and D3 were sprayed in sequence onto one side of the proton exchange membrane, defining that side as the cathode, and the spray parameters of D1, D2, and D3 were adjusted to give platinum loadings of D1, D2, and D3 of "0.2133 mg/cm, 0.1333 mg/cm, and 0.0533 mg/cm", respectively. Turning over the proton exchange membrane after cathode spraying,
the anode slurry thus configured was loaded into a spray injector, designated D4. The spraying operation was performed using D4 slurry, defined as anode, and D4 spraying parameters were adjusted to give a platinum loading of D4 of "0.1000 mg/cm. And then packaging the membrane electrode through a polyester frame, and respectively selecting the gas diffusion layers of the anode JNTGA6L and the cathode JNTGA6H for bonding to form the membrane electrode. And testing the single cell of the membrane electrode device.
Example 2 of the embodiment
Preparation of graphite carbon hydrophobing agent
10 g of Ketjen black carbon powder of EC600JD model was weighed and charged into a graphitization furnace. Ensures that the carbon powder is placed in a way that does not obstruct the circulation of the atmosphere. The furnace atmosphere was replaced three times with 99.999% high purity argon. The rate of temperature rise was set at 5 degrees celsius/min. The graphitization treatment temperature was set at 2700 degrees celsius. And (3) starting to count after the graphitization heat preservation time reaches 2700 ℃, wherein the heat preservation time is set to 8 hours. After the graphitization step is completed, the control procedure naturally cools the furnace temperature to room temperature. Taking out the graphite carbon for standby.
Preparation of cathode first coating slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 9.8500 g of a 5% by mass perfluorosulfonic acid solution and 0.0447g of graphite carbon were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D1.
Preparation of cathode second coating slurry
1.0000 g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 7.7778 g of a 5% by mass perfluorosulfonic acid solution and 0.0278 g of graphite carbon were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D2.
Preparation of cathode third coating slurry
1.0000 g of Pt/C catalyst with 50% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. A mixed solution was prepared, and 5.9740 g of a 5% by mass perfluorosulfonic acid solution and 0.0130 g of graphite carbon were weighed. To the mixed solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D3.
Preparation of anode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D4.
Membrane electrode preparation
The cathode slurries configured as described above were placed in three spray injectors, labeled D1, D2, D3, and D1, D2, and D3 were sprayed in sequence onto one side of the proton exchange membrane, defining that side as the cathode, and the spray parameters of D1, D2, and D3 were adjusted to give platinum loadings of D1, D2, and D3 of "0.2133 mg/cm, 0.1333 mg/cm, and 0.0533 mg/cm", respectively. Turning over the proton exchange membrane after cathode spraying,
the anode slurry thus configured was loaded into a spray injector, designated D4. The spraying operation was performed using D4 slurry, defined as anode, and D4 spraying parameters were adjusted to give a platinum loading of D4 of "0.1000 mg/cm. And then packaging the membrane electrode through a polyester frame, and respectively selecting the gas diffusion layers of the anode JNTGA6L and the cathode JNTGA6H for bonding to form the membrane electrode. And testing the single cell of the membrane electrode device.
Example 3
Preparation of cathode first coating slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 9.8500 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D1.
Preparation of cathode second coating slurry
1.0000 g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 7.7778 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D2.
Preparation of cathode third coating slurry
1.0000 g of Pt/C catalyst with 50% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D3.
Preparation of anode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D4.
Membrane electrode preparation
The cathode slurries configured as described above were placed in three spray injectors, labeled D1, D2, D3, and D1, D2, and D3 were sprayed in sequence onto one side of the proton exchange membrane, defining that side as the cathode, and the spray parameters of D1, D2, and D3 were adjusted to give platinum loadings of D1, D2, and D3 of "0.2133 mg/cm, 0.1333 mg/cm, and 0.0533 mg/cm", respectively. Turning over the proton exchange membrane after cathode spraying,
the anode slurry thus configured was loaded into a spray injector, designated D4. The spraying operation was performed using D4 slurry, defined as anode, and D4 spraying parameters were adjusted to give a platinum loading of D4 of "0.1000 mg/cm. And then packaging the membrane electrode through a polyester frame, and respectively selecting the gas diffusion layers of the anode JNTGA6L and the cathode JNTGA6H for bonding to form the membrane electrode. And testing the single cell of the membrane electrode device.
Example 4
Preparation of cathode first coating slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 7.7778 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D1.
Preparation of cathode second coating slurry
1.0000 g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 7.7778 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D2.
Preparation of cathode third coating slurry
1.0000 g of Pt/C catalyst with 50% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 7.7778 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D3.
Preparation of anode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D4.
Membrane electrode preparation
The cathode slurries configured as described above were placed in three spray injectors, labeled D1, D2, D3, and D1, D2, and D3 were sprayed in sequence onto one side of the proton exchange membrane, defining that side as the cathode, and the spray parameters of D1, D2, and D3 were adjusted to give platinum loadings of D1, D2, and D3 of "0.2133 mg/cm, 0.1333 mg/cm, and 0.0533 mg/cm", respectively. Turning over the proton exchange membrane after cathode spraying,
the anode slurry thus configured was loaded into a spray injector, designated D4. The spraying operation was performed using D4 slurry, defined as anode, and D4 spraying parameters were adjusted to give a platinum loading of D4 of "0.1000 mg/cm. And then packaging the membrane electrode through a polyester frame, and respectively selecting the gas diffusion layers of the anode JNTGA6L and the cathode JNTGA6H for bonding to form the membrane electrode. And testing the single cell of the membrane electrode device.
Comparative example 1
Preparation of cathode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 7.7778 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D1.
Preparation of anode slurry
1.0000 g of Pt/C catalyst with 70% Pt content is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby. The mixed solvent was prepared, and 20ml of each of absolute ethanol and isopropanol was measured and mixed and stirred for 5 minutes. 5.9740 g of a 5% by mass perfluorosulfonic acid solution was weighed. To the perfluorosulfonic acid solution, 20ml of the mixed solvent was added and stirred for 5 minutes (recorded as a), and the remaining mixed solvent was added to the wet Pt/C catalyst and subjected to ultrasonic treatment for 5 minutes (recorded as B). The above-mentioned A and B were further mixed and dispersed 6 times in order by stirring for 5 minutes/ultrasonic for 5 minutes (recorded as C). And adding the catalyst C into a shearing machine to perform dispersion treatment for 900 seconds to obtain the prepared catalyst slurry D4.
Membrane electrode preparation
The cathode slurry prepared in the above manner is placed in an injector and sprayed to one side of the proton exchange membrane, the side is defined as the cathode, and the spraying parameters of the cathode are adjusted so that the platinum loading of the cathode is 0.4000 mg/cm. Turning over the proton exchange membrane after cathode spraying,
the anode slurry prepared as described above was placed in a syringe to perform a spraying operation, defined as an anode, and the spraying parameters of the anode were adjusted so that the platinum loading of the anode was "0.1000 mg/cm. And then packaging the membrane electrode through a polyester frame, and respectively selecting the gas diffusion layers of the anode JNTGA6L and the cathode JNTGA6H for bonding to form the membrane electrode. And testing the single cell of the membrane electrode device.
The membrane electrodes prepared in "examples 1, 2, 3, 4" and comparative example 1 "were respectively put into a battery holder for performance test and electrochemical impedance spectra and polarization curves of the membrane electrodes were recorded.
The test conditions for the polarization curve were: hydrogen is introduced into the anode, air is introduced into the cathode, the humidity of the anode and the cathode is 100%, the inlet gauge pressure of the anode and the cathode is 100 kilopascals, the temperature of the battery is 80 ℃, the stoichiometric ratio of the anode is 1.5, the stoichiometric ratio of the cathode is 2.5, the test mode is a constant current mode, the step length is 2.5 amperes/test point, and each test point stays for 30s.
The electrochemical impedance spectroscopy test selected typical values of 0.1 amp/cm, 0.6 amp/cm and 1.5 amp/cm for the low, medium and high current density regions, respectively, representing the activation loss dominant region, ohmic loss dominant region and concentration loss dominant region, respectively. The single cell was operated to the target current density value for 20 minutes before testing to allow the cell to reach a steady state.
The test conditions for electrochemical impedance spectroscopy were: the initial frequency is set to 10000 hertz, the termination frequency is set to 0.1 hertz, and the amplitude of the sinusoidal alternating current excitation signal is 8% of the direct current working current.
The results of the electrochemical impedance spectroscopy are shown in tables 1, 2, 3 and 4.
TABLE 1
As can be seen from the data in table 1: the mass transfer impedance value of embodiment 1 of the present invention is smaller than that of embodiment 2. And the performance at 1.5A/cm2 was higher than that of example 2. The gradient design of the carbon nano-fiber is beneficial to the diffusion of oxygen in the cathode catalytic layer, and the performance of the membrane electrode in a high current density area is improved.
TABLE 2
As can be seen from the data in table 2: the mass transfer impedance value of embodiment 2 of the present invention is smaller than that of embodiment 3. And the performance at 1.5A/cm2 was higher than that of example 3. The gradient design of the graphite carbon is beneficial to the discharge of liquid water in the cathode catalytic layer, and the performance of the membrane electrode in a high current density area is improved.
TABLE 3 Table 3
As can be seen from the data in table 3: the ohmic resistance value of embodiment 3 of the present invention is smaller than that of embodiment 4. And the performance at 0.6A/cm2 was higher than that of example 4. The gradient design of the perfluorinated sulfonic acid resin is beneficial to the transmission of protons in the cathode catalytic layer, and improves the performance of the membrane electrode in a medium current density region.
TABLE 4 Table 4
As can be seen from the data in table 4: the activation resistance value of the embodiment example 4 of the present invention is smaller than that of the comparative example 1. And the performance at 0.1A/cm2 was higher than that of comparative example 1. The gradient design of the platinum loading is beneficial to accelerating the oxygen reduction reaction rate of the electrode surface, and improves the performance of the membrane electrode in a low current density area.
The polarization curves of the membrane electrodes prepared in examples 1, 2, 3, and 4 and comparative example 1 are shown in table 5.
TABLE 5
As can be seen from the data in table 5: the performance of inventive examples 1, 2, 3 and 4 is better than comparative example 1 in the full current density region.
Firstly, the carbon nanofiber can form a good pore structure, which is beneficial to the diffusion of oxygen in the cathode catalytic layer. The graphite carbon has better hydrophobicity and can effectively remove liquid water of the cathode catalytic layer. And the perfluorinated sulfonic acid resin is distributed in a gradient manner in the cathode catalytic layer, so that the coverage of the perfluorinated sulfonic acid resin on Pt active sites is reduced as a whole, and the transmission of oxygen to the Pt active sites is enhanced. The three designs together reduce the concentration polarization of the membrane electrode.
And secondly, the perfluorinated sulfonic acid resin distributed in a gradient manner in the cathode catalytic layer enhances the proton conductivity of the cathode catalytic layer. Both carbon nanofibers (pore-forming agent) and graphite carbon (hydrophobic agent) have excellent electrical conductivity, and the gradient design of the carbon nanofibers and graphite carbon can enhance the electron conductivity of the cathode catalytic layer. Both designs together reduce the ohmic polarization of the membrane electrode.
Thirdly, the Pt/C catalyst distributed in a gradient manner in the cathode catalytic layer can increase the catalytic activity of Pt and reduce the activation polarization of the membrane electrode. Meanwhile, the utilization rate of Pt is improved, and the cost of the membrane electrode is reduced.
Fourthly, the carbon nanofiber (pore-forming agent) and the graphite carbon (hydrophobic agent) have good stability, and the service life of the cathode catalytic layer is prolonged.
The foregoing describes one embodiment of the present invention in detail, but the description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.
Claims (10)
1. The preparation method of the gradient catalytic layer membrane electrode is characterized by comprising the following steps of:
step S1: preparing four parts of catalyst sizing agents which are D1, D2, D3 and D4 respectively;
step S2: respectively spraying D1, D2 and D3 on one side of the proton exchange membrane in sequence to form a gradient cathode catalytic layer, and defining the side as a cathode;
step S3: spraying D4 to the other side of the proton exchange membrane to form an anode catalytic layer;
step S4: and (3) attaching gas diffusion layers to the proton exchange membrane with the two sides being sprayed to package the proton exchange membrane to prepare the membrane electrode.
2. The method for preparing the gradient catalytic layer membrane electrode according to claim 1, wherein the preparation process of the catalyst slurry D1 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 9.85g of 5% by mass of perfluorosulfonic acid solution, 0.0447g of hydrophobing agent and 0.0149g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D1.
3. The method for preparing the gradient catalytic layer membrane electrode according to claim 1, wherein the preparation process of the catalyst slurry D2 comprises the following steps:
1g of Pt/C catalyst with the Pt content of 60% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 7.7778 g of 5% perfluorosulfonic acid solution, 0.0278 g of hydrophobing agent and 0.0278 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D2.
4. The method for preparing the gradient catalytic layer membrane electrode according to claim 1, wherein the preparation process of the catalyst slurry D3 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 50% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution, 0.0130 g of hydrophobing agent and 0.0390 g of pore-forming agent, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D3.
5. The method for preparing a gradient catalytic layer membrane electrode according to claim 1, wherein,
the preparation process of the catalyst slurry D4 comprises the following steps:
1g of a Pt/C catalyst with the Pt content of 70% is weighed, and ultrapure water is added to fully moisten the Pt/C catalyst for standby;
measuring 20mL of absolute ethyl alcohol and 20mL of isopropanol respectively, mixing and stirring for 5 minutes to prepare a mixed solvent;
taking 20mL of mixed solvent, adding 5.9740 g of 5% perfluorosulfonic acid solution by mass fraction, and stirring for 5 minutes to obtain a mixture A;
adding the rest mixed solvent into the wetted Pt/C catalyst, and carrying out ultrasonic treatment for 5 minutes to obtain a mixture B;
mixing the mixture A and the mixture B, and repeating the steps for 6 times in a mode of stirring for 5 minutes and then ultrasonic for 5 minutes to obtain a mixture C;
the mixture C was added to a shearing machine and dispersed for 900 seconds to obtain a prepared catalyst slurry D4.
6. The method for preparing a gradient catalytic layer membrane electrode according to any one of claims 2 to 5, wherein the Pt/C catalyst has a platinum content of 50 to 70%.
7. The method for preparing a gradient catalytic layer membrane electrode according to any one of claims 2 to 5, wherein the ion exchange equivalent of the perfluorosulfonic acid solution is 790 g/mol.
8. The method for preparing a membrane electrode assembly according to any one of claims 2 to 5, wherein the platinum loading in the anode catalytic layer is 0.1mg/cm2; the total platinum loading in the cathode catalytic layer was 0.4mg/cm2.
9. The method for preparing a gradient catalytic layer membrane electrode according to any one of claims 2 to 5, wherein the platinum loading ratio of the cathode first coating, the cathode second coating and the cathode third coating is 4:2.5:1.
10. the method for preparing a gradient catalytic layer membrane electrode according to any one of claims 2 to 5, wherein the hydrophobizing agent is graphite carbon, and the mass fractions of graphite carbon in the cathode first coating, the cathode second coating and the cathode third coating are 3%, 2% and 1%, respectively.
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| CN116259762A (en) * | 2023-02-15 | 2023-06-13 | 苏州弗尔赛能源科技股份有限公司 | Cathode side catalytic layer gradient membrane electrode, preparation method thereof and fuel cell |
| CN116364947A (en) * | 2023-03-10 | 2023-06-30 | 广东科创氢能源科技有限公司 | Fuel cell membrane electrode with gradient structure and preparation method thereof |
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| JP2008016415A (en) * | 2006-07-10 | 2008-01-24 | Toyota Motor Corp | Electrode for fuel cell, its manufacturing method, and fuel cell equipped with this electrode for fuel cell |
| CN115000420A (en) * | 2022-05-17 | 2022-09-02 | 一汽解放汽车有限公司 | Cathode catalytic membrane, membrane electrode, preparation methods of cathode catalytic membrane and membrane electrode, and fuel cell |
| CN115133043A (en) * | 2022-07-07 | 2022-09-30 | 一汽解放汽车有限公司 | Membrane electrode containing gradient cathode catalyst layer and preparation method and application thereof |
| CN116259762A (en) * | 2023-02-15 | 2023-06-13 | 苏州弗尔赛能源科技股份有限公司 | Cathode side catalytic layer gradient membrane electrode, preparation method thereof and fuel cell |
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