阅读说明：本技术 燃料电池膜电极及其制备方法、质子交换膜燃料电池 (Fuel cell membrane electrode, preparation method thereof and proton exchange membrane fuel cell ) 是由 钟青 潘牧 田明星 段奔 余丽红 郑伟倩 于 2021-08-30 设计创作，主要内容包括：本申请涉及一种燃料电池膜电极及其制备方法、质子交换膜燃料电池,属于质子交换膜燃料电池技术领域。该燃料电池膜电极包括质子交换膜以及设置在质子交换膜两侧的阴极催化剂层和阳极催化剂层。阴极催化剂层包括催化剂粉、石墨化碳粉和树脂；其中,催化剂粉为碳载金属催化剂,催化剂粉中的碳粉的比表面积大于石墨化碳粉的比表面积；石墨化碳粉上不负载金属催化剂,催化剂粉中的碳粉与石墨化碳粉的质量比为(2-4):2。该膜电极在保留了催化剂的高活性同时又提高了催化剂碳载体的耐腐蚀性能,使膜电极的耐久性能更佳。(The application relates to a fuel cell membrane electrode, a preparation method thereof and a proton exchange membrane fuel cell, belonging to the technical field of proton exchange membrane fuel cells. The fuel cell membrane electrode comprises a proton exchange membrane, and a cathode catalyst layer and an anode catalyst layer which are arranged on two sides of the proton exchange membrane. The cathode catalyst layer comprises catalyst powder, graphitized carbon powder and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2. The membrane electrode maintains the high activity of the catalyst, improves the corrosion resistance of the catalyst carbon carrier and ensures that the membrane electrode has better durability.)

1. A fuel cell membrane electrode is characterized by comprising a proton exchange membrane, and a cathode catalyst layer and an anode catalyst layer which are arranged on two sides of the proton exchange membrane;

the cathode catalyst layer comprises catalyst powder, graphitized carbon powder and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of the graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

2. The fuel cell membrane electrode assembly according to claim 1, wherein the specific surface area of the carbon powder in the catalyst powder is 700-1000m²(g), the graphitized carbon powderHas a specific surface area of 50-150m²/g。

3. The fuel cell membrane electrode assembly according to claim 2 wherein said catalyst powder is a carbon-supported platinum catalyst powder and the mass percent of platinum is 40-60%.

4. The fuel cell membrane electrode assembly according to any one of claims 1 to 3, wherein the anode catalyst layer comprises catalyst powder, graphitized carbon powder, and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of the graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

5. A method of preparing a fuel cell membrane electrode assembly according to any one of claims 1 to 4, comprising:

mixing the catalyst powder, the graphitized carbon powder, a resin solution and a solvent to obtain cathode catalyst slurry, preparing the cathode catalyst layer through the cathode catalyst slurry, forming the cathode catalyst layer on the cathode side of the proton exchange membrane, and then forming the anode catalyst layer on the anode side of the proton exchange membrane.

6. The preparation method of claim 5, wherein the catalyst slurry is coated on the cathode side of the proton exchange membrane and then dried to obtain a cathode catalyst layer.

7. The preparation method according to claim 5, wherein the cathode catalyst slurry is coated on a transfer film, and then dried to obtain a cathode catalyst layer, and then the cathode catalyst layer is transferred to the cathode side of the proton exchange membrane.

8. The method of claim 7The preparation method is characterized in that the transfer printing conditions are as follows: the transfer temperature is 120-160 ℃, and the transfer pressure is 50-200kgf/cm²。

9. The production method according to any one of claims 5 to 8, characterized in that the mass ratio of the resin solution to the carbon powder in the catalyst slurry is (0.6-1):1, and the resin solution is a resin solution having a mass percentage of 5-10%; the mass ratio of the solvent to the carbon powder in the catalyst powder is (2-6) to 1.

10. A proton exchange membrane fuel cell comprising a fuel cell membrane electrode according to any one of claims 1 to 4.

Technical Field

The application relates to the technical field of proton exchange membrane fuel cells, in particular to a fuel cell membrane electrode, a preparation method thereof and a proton exchange membrane fuel cell.

Background

The membrane electrode is an important component of a fuel cell stack and is where electrochemical reactions occur. The membrane electrode comprises a proton exchange membrane, a cathode catalyst layer positioned on the cathode side of the proton exchange membrane, an anode catalyst layer positioned on the anode side of the proton exchange membrane, a cathode diffusion layer positioned on the cathode catalyst layer and deviating from the proton exchange membrane, and an anode diffusion layer positioned on the anode catalyst layer and deviating from the proton exchange membrane. Among them, the catalytic activity of the catalysts in the cathode catalyst layer and the anode catalyst layer directly affects the output performance of the stack. In the actual operation of a vehicle, a hydrogen-air interface is easily formed under the starting and stopping working conditions of the proton exchange membrane fuel cell, and carbon corrosion may occur after high potential is formed, so that the catalytic activity of a catalyst is reduced, and the performance of the fuel cell is reduced. Therefore, it is very important to improve the durability of the carrier of the catalyst.

At present, commercial catalyst carriers for fuel cells are usually carbon powder, and carbon materials have the characteristics of high specific surface area, good dispersibility, high conductivity, good heat and mass transfer and the like, so that the electrochemical surface area of noble metal Pt can be greatly improved in the fuel cell catalyst, the utilization rate of Pt is improved, the consumption of Pt is reduced, and the cost of the fuel cell is further reduced. With the increasing demand of people on the output power of the battery, the activity of the membrane electrode catalyst is also increased, and in order to obtain high electrochemical activity, the carbon carrier with high specific surface area is selected as a better choice, but another problem to be solved is also brought, the carbon carrier with high specific surface area has poor corrosion resistance to high potential, and the result that the output performance of the membrane electrode is rapidly reduced due to collapse of the carbon carrier and loss of Pt after short-time high potential circulation.

In order to solve the problem that the carbon carrier is easy to corrode and obtain a high-performance and high-durability catalyst, some researches are also made, for example, the carbon carrier with a high specific surface area is replaced by a graphitized carbon carrier, and finally, the durability of the catalyst carrier is found to be improved, but the graphitized carbon has a smooth surface, and Pt particles are difficult to deposit on the surface after loss, so that the performance of a membrane electrode is reduced, and the requirements of technical indexes cannot be met. In addition, researchers also perform high-temperature treatment on the carbon powder with high specific surface area to improve the corrosion resistance of the catalyst, but the carbon carrier is of a porous structure, and after the high-temperature treatment, a large number of micropores collapse, so that the specific surface area is reduced, and the load of the catalyst is reduced.

Disclosure of Invention

As the carbon corrosion phenomenon of the catalyst carbon carrier can occur in the starting and stopping processes of the vehicle, the catalyst is irreversibly damaged, the activity of the catalyst is greatly reduced, and the output performance of the fuel cell is reduced. If graphitized carbon is used as the carrier, although the corrosion resistance is enhanced, the catalytic activity is affected. Therefore, high activity and high durability are contradictory directions in the catalyst preparation process, and both cannot have high characteristics at the same time.

In view of the shortcomings of the prior art, the embodiments of the present application provide a fuel cell membrane electrode, a preparation method thereof, and a proton exchange membrane fuel cell, which can improve the durability of a catalyst without reducing the activity of the catalyst.

In a first aspect, embodiments of the present application provide a fuel cell membrane electrode, including a proton exchange membrane, and a cathode catalyst layer and an anode catalyst layer disposed on both sides of the proton exchange membrane. The cathode catalyst layer comprises catalyst powder, graphitized carbon powder and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

During the starting and stopping process of the fuel cell, the situation of transient high potential can occur at the cathode, and at the moment, the carbon carrier in the high-specific surface area and high-activity carbon-supported metal catalyst is easy to corrode, so that the structure of a catalyst layer is damaged, and the irreversible performance of the cell is attenuated. After the graphitized carbon powder is added into the cathode catalyst layer, the carbon with high specific surface area and the graphitized carbon can be corroded at the same time under high potential, but because the area covered by the metal particles outside the carbon carrier with high specific surface area is larger, the graphitized carbon powder is completely exposed outside, the carbon corrosion reaction needs the participation of water, and the graphitized carbon is exposed outside and directly contacts with the water, so more graphitized carbon is corroded, and the corrosion degree of the carbon carrier with high specific surface area is reduced. The high activity of the catalyst is kept, and simultaneously, the corrosion resistance of the catalyst carbon carrier is improved, so that the durability of the membrane electrode is better.

In some embodiments of the present application, the specific surface area of the carbon powder in the catalyst powder is 700-1000m²The specific surface area of the graphitized carbon powder is 50-150m²(ii) in terms of/g. The specific surface area of the carbon powder is large, so that the electrochemical active area of the metal particles can be large after the metal particles are loaded, and the high activity of the catalyst can be kept; although the specific surface area of the graphitized carbon powder is small, the activity of the catalyst is not influenced because metal particles are not loaded on the graphitized carbon powder, and the graphitized carbon powder has strong corrosion resistance, so that the corrosion resistance of the catalyst can be obviously improved, and the durability of the catalyst is enhanced.

In some embodiments of the present application, the catalyst powder is carbon-supported platinum catalyst powder, and the mass percentage of platinum is 40-60%. The carbon carrier has a large specific surface area, so that the content of platinum can be high, and meanwhile, the platinum loaded on the carbon carrier has a large electrochemical active area, so that the power generation capacity can be increased, and the high activity of the catalyst can be ensured.

In some embodiments of the present application, the anode catalyst layer includes catalyst powder, graphitized carbon powder, and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

Under abnormal working conditions (such as a counter-electrode working condition), the carbon carrier in the anode catalyst layer may be corroded to a certain extent, so that the anti-counter-electrode performance of the membrane electrode can be enhanced by adding graphitized carbon powder in the anode catalyst layer.

In a second aspect, the present application provides a method of making a fuel cell membrane electrode, comprising: mixing catalyst powder, graphitized carbon powder, resin solution and solvent to obtain cathode catalyst slurry, preparing a cathode catalyst layer through the cathode catalyst slurry, forming the cathode catalyst layer on the cathode side of the proton exchange membrane, and then forming an anode catalyst layer on the anode side of the proton exchange membrane.

Firstly, uniformly mixing catalyst powder (the catalyst powder is a carbon-supported metal catalyst) and graphitized powder (the graphitized carbon powder is not supported with a metal catalyst), and then preparing to obtain a cathode catalyst layer. The cathode catalyst layer can uniformly corrode the graphitized carbon carrier under the condition of high potential, so that the corrosion degree of the carbon carrier with high specific surface area is reduced, the high activity of the catalyst is kept, the corrosion resistance of the carbon carrier of the catalyst is improved, and the durability of the membrane electrode is better.

In some examples of the present application, the cathode catalyst slurry is coated on the cathode side of the proton exchange membrane and then dried to obtain the cathode catalyst layer. The preparation of the catalyst layer may be performed by a direct coating method.

In some embodiments of the present disclosure, the catalyst slurry is coated on a transfer film, and then dried to obtain a cathode catalyst layer, and the cathode catalyst layer is transferred to the cathode side of the proton exchange membrane. The preparation of the catalyst layer may be performed by a transfer method.

In some embodiments of the present application, the transfer conditions are: the transfer temperature is 120-160 ℃, and the transfer pressure is 50-200kgf/cm². The addition of the graphitized carbon powder does not affect the preparation method and the preparation conditions of the catalyst layer, so that the preparation method of the membrane electrode is simpler.

In some examples of the application, in the catalyst slurry, the mass ratio of the resin solution to the carbon powder in the catalyst powder is (0.6-1):1, and the resin solution is 5-10% by mass; the mass ratio of the solvent to the carbon powder in the catalyst powder is (2-6) to 1. The components in the catalyst slurry can be mixed more uniformly.

In a third aspect, the present application provides a proton exchange membrane fuel cell comprising the above fuel cell membrane electrode. The fuel cell uses the membrane electrode, can maintain the high activity of the catalyst and simultaneously improve the corrosion resistance of the catalyst carbon carrier, so that the membrane electrode has better durability.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a first process flow diagram for preparing a fuel cell membrane electrode assembly according to an embodiment of the present disclosure;

FIG. 2 is a second process flow diagram for preparing a fuel cell membrane electrode assembly according to an embodiment of the present disclosure;

fig. 3 is an XRD contrast diagram of the catalyst layers provided in example 1 and comparative example 1;

fig. 4 is an I-V graph of the membrane electrodes provided in example 1 and comparative example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the present application are described below clearly and completely.

The application provides a proton exchange membrane fuel cell, the core part of which is a fuel cell membrane electrode, and the fuel cell membrane electrode comprises a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer. The cathode catalyst layer is arranged on the cathode side of the proton exchange membrane, the anode catalyst layer is arranged on the anode side of the proton exchange membrane, the cathode diffusion layer is arranged on the surface, deviating from the proton exchange membrane, of the cathode catalyst layer, and the anode diffusion layer is arranged on the surface, deviating from the proton exchange membrane, of the anode catalyst layer.

In the present application, in order to maintain both high activity and durability of the catalyst layer of the membrane electrode. The cathode catalyst layer comprises catalyst powder, graphitized carbon powder and resin; the catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2. It should be noted that: the anode catalyst layer may also contain graphitized carbon powder, but the components of the anode catalyst layer and the components of the cathode catalyst layer are not limited to be the same, and may be the same or different, and may be within the above range, and the present application is not limited thereto.

In the starting and stopping process of the fuel cell, the situation of transient high potential is more likely to occur at the cathode, so firstly, graphitized carbon powder is added into the cathode catalyst layer; the anode may also have carbon corrosion problem according to the actual operation condition of the membrane electrode, so that graphitized carbon powder can be selectively added into the anode catalyst layer.

Fig. 1 is a first process flow diagram for preparing a fuel cell membrane electrode according to an embodiment of the present disclosure.

Referring to fig. 1, the method for preparing the membrane electrode of the fuel cell includes the following steps:

and S110, mixing the catalyst powder, the graphitized carbon powder, the resin solution and the solvent to obtain catalyst slurry. The catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

Optionally, the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-3):2, or the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (3-4): 2. Illustratively, the mass ratio of the carbon powder to the graphitized carbon powder in the catalyst powder is 2:2, 2.5:2, 3:2, 3.5:2, or 4: 2.

Optionally in a catalyst powderThe specific surface area of the carbon powder is 700-1000m²The specific surface area of the graphitized carbon powder is 50-150m²(ii) in terms of/g. The specific surface area of the carbon powder is large, so that the electrochemical active area of the metal particles can be large after the metal particles are loaded, and the high activity of the catalyst can be kept; although the specific surface area of the graphitized carbon powder is small, the activity of the catalyst is not influenced because metal particles are not loaded on the graphitized carbon powder, and the graphitized carbon powder has strong corrosion resistance, so that the corrosion resistance of the catalyst can be obviously improved, and the durability of the catalyst is enhanced.

In some possible embodiments, the specific surface area of the carbon powder in the catalyst powder is 700-800m²(g) or the specific surface area of the carbon powder in the catalyst powder is 800-²(g) or the specific surface area of the carbon powder in the catalyst powder is 900-²(ii)/g; the specific surface area of the graphitized carbon powder is 50-100m²The specific surface area of the/g or graphitized carbon powder is 100-150m²/g。

Illustratively, the specific surface area of the carbon powder in the catalyst powder is 700m²/g、750m²/g、800m²/g、850m²/g、900m²/g、950m²In g or 1000m²(ii)/g; the specific surface area of the graphitized carbon powder is 50m²/g、80m²/g、100m²/g、120m²G or 150m²/g。

In one embodiment, the catalyst powder is a carbon-supported platinum catalyst powder, and the mass percentage of platinum is 40% -60%. The carbon carrier has a large specific surface area, so that the content of platinum can be high, and meanwhile, the platinum loaded on the carbon carrier has a large electrochemical active area, so that the power generation capacity can be increased, and the high activity of the catalyst can be ensured.

The carbon-supported platinum catalyst may be a carbon-supported platinum simple substance or a carbon-supported platinum alloy, and the application is not limited. Illustratively, the platinum-carrying catalyst powder has a platinum content of 40%, 45%, 50%, 55%, or 60% by mass.

In other embodiments, the catalyst powder may be iridium on carbon, iridium alloy on carbon, ruthenium alloy on carbon, or the like, and the present application is not limited thereto.

The catalyst powder and the graphitized carbon powder satisfy the above conditions, and the catalyst layer prepared from the catalyst slurry also satisfies the above conditions, which are not described herein again.

In the catalyst slurry, the mass ratio of the resin solution to the carbon powder in the catalyst powder is (0.6-1):1, and the resin solution is 5-10% by mass; the mass ratio of the solvent to the carbon powder in the catalyst powder is (2-6) to 1. After the catalyst layer is prepared from the catalyst slurry, the resin solution is dried to obtain a resin, and the solvent is evaporated after being dried.

Optionally, in the catalyst slurry, the mass ratio of the resin solution to the carbon powder in the catalyst powder is (0.6-8):1, or the mass ratio of the resin solution to the carbon powder in the catalyst powder is (0.8-1): 1; the mass ratio of the solvent to the carbon powder in the catalyst powder is (2-4):1, or the mass ratio of the solvent to the carbon powder in the catalyst powder is (4-6): 1.

Illustratively, the mass ratio of the resin solution to the carbon powder in the catalyst powder is 0.6:1, 0.7:1, 0.8:1, 0.9:1, or 1: 1; the mass ratio of the solvent to the carbon powder in the catalyst powder is 2:1, 3:1, 4:1, 5:1 or 6: 1. The mass percentage of the resin solution is 5%, 6%, 7%, 8%, 9% or 10%.

Wherein, the solvent comprises water and/or alcohol, the solvent can be water, the solvent can also be alcohol, and the solvent can also be a mixture of water and alcohol; the alcohol may be methanol, ethanol, propanol, isopropanol, etc., and the present application is not limited thereto.

The resin solution may be one or more of a perfluorosulfonic acid resin solution, a perfluorocarboxylic acid resin solution, a sulfonated polyether ether ketone resin solution and a sulfonated polysulfone resin solution, and if there are a plurality of these, the mass percentage of each resin solution may be 5 to 10%.

And S120, coating the catalyst slurry on the cathode side of the proton exchange membrane, and drying to obtain a cathode catalyst layer. Optionally, the catalyst slurry prepared in step S110 is coated on the cathode side of the proton exchange membrane, and then dried at a temperature of 80-100 ℃ to form a cathode catalyst layer on the cathode side of the proton exchange membrane.

OptionallyThe platinum loading in the cathode catalyst layer is 0.3-0.5mg/cm². Illustratively, the loading of platinum in the cathode catalyst layer is 0.3mg/cm²、0.35mg/cm²、0.4mg/cm²、0.45mg/cm²Or 0.5mg/cm²。

And S130, coating the catalyst slurry on the anode side of the proton exchange membrane, and drying to obtain an anode catalyst layer. Optionally, the catalyst slurry prepared in step S110 is coated on the anode side of the proton exchange membrane, and then dried at a temperature of 80-100 ℃ to form an anode catalyst layer on the anode side of the proton exchange membrane. The anti-reversal performance of the membrane electrode can be enhanced.

The catalyst slurry for preparing the anode catalyst layer may not be the catalyst slurry prepared in step S110, or may be the catalyst slurry without adding graphitized carbon powder, and the present application is not limited thereto.

Optionally, the loading of platinum in the anode catalyst layer is 0.05-0.15mg/cm². Illustratively, the loading of platinum in the anode catalyst layer is 0.05mg/cm²、0.1mg/cm²Or 0.15mg/cm²。

Fig. 2 is a second process flow diagram for preparing a fuel cell membrane electrode according to an embodiment of the present disclosure. Referring to fig. 2, the method for preparing the membrane electrode of the fuel cell includes the following steps:

s210, mixing the catalyst powder, the graphitized carbon powder, the resin solution and the solvent to obtain catalyst slurry. The catalyst powder is a carbon-supported metal catalyst, and the specific surface area of carbon powder in the catalyst powder is larger than that of graphitized carbon powder; the graphitized carbon powder is not loaded with a metal catalyst, and the mass ratio of the carbon powder in the catalyst powder to the graphitized carbon powder is (2-4): 2.

The catalyst slurry may be the same as the catalyst slurry in step S110, and will not be described herein.

And S220, coating the catalyst slurry on the transfer printing film, and drying to obtain the cathode catalyst layer. And coating the catalyst slurry on the transfer printing film, and drying to obtain the anode catalyst layer.

Optionally, the catalyst slurry prepared in step S110 is coated on a transfer film, and then dried at a temperature of 80 to 100 ℃ to form a cathode catalyst layer on the transfer film. And coating the catalyst slurry prepared in the step S110 on a transfer printing film, and drying the transfer printing film at the temperature of 80-100 ℃ to form an anode catalyst layer on the transfer printing film. At this time, graphitized carbon powder is added to both the anode catalyst layer and the cathode catalyst layer.

In other embodiments, no graphitized carbon powder is added to the catalyst slurry for preparing the anode catalyst layer. The obtained anode catalyst layer is not added with graphitized carbon powder, and the cathode catalyst layer is added with graphitized carbon powder.

And S230, respectively transferring the cathode catalyst layer and the anode catalyst layer to the cathode side and the anode side of the proton exchange membrane.

Optionally, a proton exchange membrane is sandwiched between the cathode catalyst layer and the anode catalyst layer at a temperature of 120-²The transfer printing is performed under the conditions of (1) and (3) the transfer printing film is removed. The transfer film may be a polytetrafluoroethylene film, a release film, or the like, which is not limited in this application.

According to the fuel cell membrane electrode prepared by the method, at least the cathode catalyst layer contains graphitized carbon powder, and under high potential, high specific surface area carbon and graphitized carbon can be corroded at the same time, but because the area covered by metal particles outside the high surface area carbon carrier is larger, the graphitized carbon powder is completely exposed outside, the carbon corrosion reaction needs the participation of water, and the graphitized carbon is exposed outside and directly contacts with water, so that more graphitized carbon is corroded, and the corrosion degree of the high specific surface area carbon carrier is reduced. The high activity of the catalyst is kept, and simultaneously, the corrosion resistance of the catalyst carbon carrier is improved, so that the durability of the membrane electrode is better.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

The embodiment provides a preparation method of a fuel cell membrane electrode, which comprises the following steps:

(1) 50% of carbon-supported platinum catalyst powder (the specific surface area of the carbon powder is 900 m)²(g)) graphitized carbon powder (the specific surface area of the carbon powder is 100m²And/g), 5 percent by mass of perfluorosulfonic acid resin solution (isopropanol is used as a solvent) and a solvent (water and isopropanol in a mass ratio of 1: 1) are mixed, and the mixture is ultrasonically and uniformly prepared into cathode catalyst slurry. Wherein, the carbon powder in the carbon-supported platinum catalyst: graphitizing carbon powder: the mass ratio of the resin solution to the solvent is 3:2:0.3: 12.

(2) 50% of carbon-supported platinum catalyst powder (the specific surface area of the carbon powder is 900 m)²And/g), and 5% by mass of a perfluorosulfonic acid resin solution (the solvent is isopropanol) and a solvent (water and isopropanol in a mass ratio of 1: 1) are mixed, and the mixture is ultrasonically and uniformly prepared into anode catalyst slurry. Wherein, the carbon powder in the carbon-supported platinum catalyst: the mass ratio of the resin solution to the solvent was 3:0.3: 12.

(3) Respectively and uniformly coating the catalyst slurry prepared in the step (1) and the step (2) on a flat polytetrafluoroethylene membrane, and then drying the polytetrafluoroethylene membrane at 90 ℃ to respectively obtain the platinum loading capacity of 0.4mg/cm²And the platinum loading was 0.1mg/cm²Then a 12 μm proton exchange membrane is sandwiched between polytetrafluoroethylene membranes coated with a cathode catalyst layer and an anode catalyst layer, respectively, and the membrane is placed at 140 ℃ under a pressure of 100kgf/cm²The heating plate is heated and pressed for 4min, then the heating plate is taken out, and the heating plate is placed between two cooling plates at 20 ℃ for cooling for 5min, so that the cooling process is completed. And taking out the cooled membrane, quickly tearing off the polytetrafluoroethylene membranes on the two sides of the cathode and the anode, transferring the catalyst layer onto the proton exchange membrane, and then attaching a common frame and a diffusion layer on the two sides to prepare the 7-MEA.

Example 2

Example 2 is an improvement on example 1, and example 2 and exampleThe differences between 1 are: the specific surface area of the graphitized carbon powder is 150m²/g。

Example 3

Example 3 is a modification of example 1, and example 3 differs from example 1 in that: the specific surface area of the carbon powder in the carbon-supported platinum catalyst powder is 800m²/g。

Example 4

Example 4 is a modification of example 1, and example 4 differs from example 1 in that: the anode catalyst slurry was identical to the cathode catalyst slurry in example 1, and graphitized carbon powder was added thereto.

Comparative example 1

Comparative example 1 is an improvement over example 1, and comparative example 1 differs from example 1 in that: graphitized carbon powder is not added into the cathode catalyst layer and the anode catalyst layer.

Comparative example 2

Comparative example 2 is an improvement over example 1, and comparative example 2 differs from example 1 in that: the graphitized carbon powder in the cathode catalyst layer and the anode catalyst layer are both loaded with metal platinum, and the loading amount of the platinum in the cathode catalyst layer is 0.4mg/cm²The platinum loading in the anode catalyst layer was 0.1mg/cm²And the total amount of platinum in the catalyst layer was the same as in example 1.

Experimental example 1

Fig. 3 is an XRD contrast diagram of the catalyst layers provided in example 1 and comparative example 1, wherein the graphite powder doped high specific surface area C is an XRD diagram of the catalyst layer provided in example 1; the high specific surface area C is the XRD pattern of the catalyst layer provided in comparative example 1. As can be seen from fig. 3, after the high specific surface area C supported Pt catalyst is doped with graphitized carbon powder, the peak of graphitized C is significantly enhanced, which indicates that the graphitized carbon powder is effectively mixed into the catalyst, and no other impurity elements are introduced.

The membrane electrodes provided in example 1 and comparative example 1 were tested, wherein fig. 4 is an I-V graph of the membrane electrodes provided in example 1 and comparative example 1. Wherein, BOL before C doping and after high potential corrosion before C doping refer to the pairThe initial performance and the performance after high potential corrosion of the membrane electrode provided by the proportion 1; after BOL after C doping and after high potential etching after C doping, refer to the initial performance and the performance after high potential etching of the membrane electrode provided in example 1. As can be seen from FIG. 4, CA-0C @1.2A/cm of the membrane electrode provided in example 1²Is 0.71V, CA-5000C @1.2A/cm²Is 0.63V, 1.2A/cm²The lower voltage is attenuated by 80 mV; CA-0C @1.2A/cm for the membrane electrode provided in comparative example 1²Is 0.71V, CA-5000C @1.2A/cm²Is 0.27V, 1.2A/cm²The lower voltage decays 440 mV. It can be shown that the membrane electrode provided in example 1 has a high initial performance activity and a small performance degradation after a period of high potential corrosion, indicating that the requirement of high activity and durability is satisfied at the same time.

The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.