CN103170928B - The fixture shaping for membrane electrode of fuel batter with proton exchange film and the preparation method of membrane electrode of fuel batter with proton exchange film - Google Patents

Abstract

The invention provides the preparation method of a kind of fixture shaping for membrane electrode of fuel batter with proton exchange film and membrane electrode of fuel batter with proton exchange film, membrane electrode assembly is positioned over first dull and stereotyped and the second dull and stereotyped centre of fixture by the method successively; The moment of torsion of the lead screw of fixture is set to 0.5Nm ~ 5Nm, clamp screw screw mandrel is held out against the second flat board by the screw hole of the first flat board; At 140 DEG C ~ 250 DEG C, heat described fixture, after 2min ~ 30min, obtain membrane electrode of fuel batter with proton exchange film.The present invention adopts the fixture of the composition such as the first flat board and the second flat board, adjusts, makes the discharge performance of membrane electrode comparatively excellent, and then can improve the chemical property of fuel cell to the press moulding mode preparing membrane electrode.The present invention prepares membrane electrode, and method is simple, and without the need to introducing expensive molding apparatus, cost is lower, is beneficial to popularization.

Description

Fixture for forming proton exchange membrane fuel cell membrane electrode and preparation method of proton exchange membrane fuel cell membrane electrode

technical field

The invention relates to the field of fuel cells, in particular to a fixture for forming a membrane electrode of a proton exchange membrane fuel cell and a method for preparing the membrane electrode of a proton exchange membrane fuel cell.

Background technique

A fuel cell is a power generation device that converts chemical energy directly into electrical energy through an electrochemical reaction. Compared with traditional energy conversion systems, fuel cells have many advantages: for example, they are not limited by the Carnot cycle, and the energy conversion efficiency is high; the product is usually water, which has little environmental pollution. Therefore, fuel cells have received increasing attention in recent years.

Among fuel cells, a proton exchange membrane fuel cell is a device that uses fuels such as methanol, hydrogen, and formic acid to generate electricity through a membrane electrode composed of an ion exchange membrane and a catalyst electrode. Among them, when the hydrogen-oxygen proton exchange membrane fuel cell is working, the reaction that occurs is as follows:

Anode reaction: H ₂ → 2H ⁺ +2e;

Cathode reaction: 1/2O ₂ +2H ⁺ +2e→H ₂ O;

Total reaction: H ₂ +1/2O ₂ →H ₂ O.

In a proton exchange membrane fuel cell, the membrane electrode is one of its core components. Membrane electrodes generally include an anode diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer and a cathode diffusion layer arranged in sequence. At present, the membrane electrode is usually prepared according to the following method: first, the anode catalytic layer and the cathode catalytic layer are respectively prepared on the surface of the anode diffusion layer and the cathode diffusion layer to obtain the catalyst anode layer and the catalyst cathode layer respectively, and then the ion exchange membrane is placed on the catalyst anode layer Between the cathode layer and the catalyst cathode layer, it is pressed into one body by hot pressing method, so as to obtain the membrane electrode. On this basis, the existing technology starts from the structure of membrane electrodes, catalysts and ion exchange membranes, and provides a variety of methods to improve the electrochemical performance of fuel cells, such as the Chinese patent literature with application number 200710144386.3 and application number is Chinese patent documents of 200810046956.X, etc.

However, the existing technology is to directly use the traditional hot pressing method to prepare the membrane electrode. If a high-precision molding machine is not introduced, the obtained membrane electrode will have poor bonding strength, which will affect its discharge performance and is not conducive to further improving the proton Electrochemical performance of exchange membrane fuel cells.

Contents of the invention

In order to solve the above technical problems, the present invention provides a fixture for forming a membrane electrode of a proton exchange membrane fuel cell and a method for preparing the membrane electrode of a proton exchange membrane fuel cell. The membrane electrode prepared by the invention has excellent discharge performance, and the preparation method is simple and easy, without introducing expensive molding equipment.

The invention provides a fixture for forming a membrane electrode of a proton exchange membrane fuel cell, comprising:

A first flat panel and a second flat panel placed in parallel, the space between the first flat panel and the second flat panel is a storage area;

Both the first plate and the second plate are provided with through holes, and the screw rod connects the first plate and the second plate through the through holes;

The first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole.

Preferably, the torque of the screw rod is 0.5N·m˜5N·m.

Preferably, the first plate has at least four through holes, which are symmetrically distributed at the four corners of the first plate.

Preferably, the first plate has at least four screw holes, symmetrically distributed in the edge area of the first plate.

Preferably, the first flat plate is a steel plate or an alloyed aluminum plate, and the second flat plate is a steel plate or an alloyed aluminum plate.

The present invention also provides a method for preparing a proton exchange membrane fuel cell membrane electrode, comprising:

The anode diffusion layer, the anode catalyst layer, the proton exchange membrane layer, the cathode catalyst layer, and the cathode diffusion layer are sequentially placed between the first flat plate and the second flat plate placed in parallel, and the first flat plate and the second flat plate are provided with through hole, the screw rod connects the first plate and the second plate through the through hole;

The torque of the screw rod is set to 0.5N·m～5N·m, the first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole to complete the fixation;

The fixed first plate, the second plate, and the anode diffusion layer, anode catalyst layer, proton exchange membrane layer, cathode catalyst layer, and cathode diffusion layer placed between the first plate and the second plate in sequence were placed at 140°C. Heating at ~250° C. for 2 minutes to 30 minutes to obtain a proton exchange membrane fuel cell membrane electrode.

Preferably, the heating temperature is 180°C to 210°C.

Preferably, the heating time is 10 minutes to 20 minutes.

Preferably, the first flat plate is a steel plate or an alloyed aluminum plate, and the second flat plate is a steel plate or an alloyed aluminum plate.

Preferably, the anode diffusion layer is carbon paper or carbon cloth, the cathode diffusion layer is carbon paper or carbon cloth, the anode catalyst of the anode catalyst layer is a PtRu black catalyst or a PtRu/C catalyst, and the cathode catalyst layer The cathode catalyst is Pt black catalyst or Pt/C catalyst.

Compared with the prior art, the present invention first places each layer of the membrane electrode between the first flat plate and the second flat plate in sequence, and the first flat plate and the second flat plate are placed in parallel and connected by a screw rod; then the The torque of the screw rod is set to 0.5N·m～5N·m, and the set screw rod is pressed against the second plate through the screw hole of the first plate, so that the first plate and the second plate are connected and fixed and then heating the fixed first plate, the second plate, and the layers between the first plate and the second plate, the temperature of the heating is 140°C-250°C, and the time is 2min-30min, Thus, the membrane electrode of the proton exchange membrane fuel cell is obtained.

The invention adopts the jig composed of the first flat plate and the second flat plate, etc., and adjusts the molding method for preparing the membrane electrode. In the present invention, the torque is controlled to 0.5N·m～5N·m, and under the pressure of the plate, it is ensured that the plate exerts a suitable pressing force on each layer of the membrane electrode during the heating process, so that each layer can be fully and evenly contacted. The present invention is screwed into the set screw rod in the screw hole of the first flat plate, and the second flat plate is pressed against, so that each layer is not easily deformed during the heating process, thereby ensuring that the anode diffusion layer and the cathode diffusion layer of the membrane electrode made etc. have higher porosity to ensure the unimpeded transport of protons, electrons, gases and liquids; at the same time, the present invention controls the heating temperature and time to ensure that each layer has a higher bonding strength, so that the discharge It has excellent performance and can prolong the cycle life of the fuel cell, thereby further improving the electrochemical performance of the fuel cell. Experiments have proved that the membrane electrode prepared by the method of the present invention has relatively excellent discharge performance, and its preparation process is simple and easy to operate, without the need to introduce expensive molding equipment such as high-precision molding machines, and the cost is low, which is conducive to popularization.

Description of drawings

FIG. 1 is a schematic structural view of a clamp for forming a proton exchange membrane fuel cell membrane electrode provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the placement of the jig and the raw materials of each layer of the membrane electrode provided by the embodiment of the present invention;

Fig. 3 is the voltage and power curves measured by discharging the membrane electrode prepared in Example 1 of the present invention with 3M methanol solution at 25°C;

Fig. 4 is the voltage and power curves measured by discharging the membrane electrode prepared in Example 2 of the present invention with 3M methanol solution at 25°C;

Fig. 5 is the measured voltage and power curves when the membrane electrode prepared in Comparative Example 1 is discharged with 3M methanol solution at 25°C.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention, rather than limiting the claims of the present invention.

The invention provides a fixture for forming a membrane electrode of a proton exchange membrane fuel cell, comprising:

A first flat panel and a second flat panel placed in parallel, the space between the first flat panel and the second flat panel is a storage area;

Both the first plate and the second plate are provided with through holes, and the screw rod connects the first plate and the second plate through the through holes;

The first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole.

The clamp provided by the invention can be used for forming the membrane electrode of the proton exchange membrane fuel cell, and can improve the performance such as the discharge performance of the membrane electrode.

The structure of the jig for forming the membrane electrode of the proton exchange membrane fuel cell provided by the embodiment of the present invention is shown in Figure 1, and Figure 1 is a schematic structural diagram of the jig for forming the membrane electrode of the proton exchange membrane fuel cell provided by the embodiment of the present invention . In Fig. 1, 11 is a first flat plate, 12 is a second flat plate, 41 is a screw rod, and 42 is a set screw rod.

In the present invention, the first flat plate 11 and the second flat plate 12 are placed in parallel, and the space between the two is a storage area, which can be used to place the raw materials of each layer of the membrane electrode such as the anode catalyst layer, the proton exchange membrane layer and the cathode diffusion layer. .

The first flat plate is preferably a steel plate or an alloy aluminum plate. Such a plate has good thermal conductivity, high heat resistance and a small expansion coefficient, which is more beneficial to the preparation of a membrane electrode using the fixture; the second flat plate is preferably a steel plate or an alloy As for the aluminum plate, the plates of the two plates can be the same or different, and the same plate is preferred. In the present invention, there is no special limitation on the areas of the first flat plate and the second flat plate, which may be determined according to the area of the membrane electrode to be prepared.

Both the first plate 11 and the second plate 12 are provided with through holes corresponding to each other, and the screw rod 41 connects them through the through holes. The screw rod 41 can not only connect and fix the first plate 11 and the second plate 12, but also adjust the pressing force between the two plates.

The present invention has no special restrictions on the through holes and screw rods, as long as they can play the above functions, such as hexagon socket screw rods can be used; in order to ensure that the first flat plate 11 and the second flat plate 12 have a uniform The pressure of the first plate is preferably at least four, which are symmetrically distributed at the four corners of the first plate. Correspondingly, the number of screw rods 41 is also preferably four.

During operation, the torque of the screw rod 41 is preferably 0.5N·m˜5N·m. The pressing force provided by the above torque is sufficient to ensure full and smooth contact of each layer of the membrane electrode. If the torque is too large, it will lead to excessive pressure of the flat plate on each layer of the membrane electrode in the subsequent heating process, resulting in deformation or even rupture of the anode diffusion layer, cathode diffusion layer and proton exchange membrane layer, thereby affecting the porosity and support. strength, making it difficult for the catalyst to function properly. For a membrane electrode with an area of less than 20 cm ² , the torque of the screw 41 is more preferably 0.8 N·m to 3 N·m; for a membrane electrode with an area of less than 10 cm ² , preferably 4 cm ² to 10 cm ² , the torque of the screw 41 is more preferred It is 0.8N·m～1.3N·m.

In order to avoid extra pressure on the membrane electrode due to the weight of the heating plate during the heating process for preparing the membrane electrode, the first plate 11 is also provided with a screw hole through which the set screw rod 42 tightens the second plate 12 . The set screw rod passes through the screw hole arranged on the first plate, and the lower end is against the second plate, thus ensuring that the distance between the two plates remains substantially constant during the heating process, thereby protecting the membrane electrode during the preparation process. No deformation due to undesired stress.

The present invention has no special restrictions on the screw holes and set screw rods, as long as they can play the above-mentioned functions, such as hexagon socket set screw rods can be used; in order to further ensure that the first flat plate 11 and the second flat plate 12 are sandwiched between The pressure applied by the membrane electrode is uniform, and the screw holes of the first flat plate are preferably at least four, which are symmetrically distributed in the edge area of the first flat plate. Correspondingly, the number of set screw rods 42 is also preferably four .

Fig. 2 is a schematic diagram of the fixture provided by the embodiment of the present invention and the placement of each layer of raw materials for the membrane electrode, wherein 11 is the first flat plate, 12 is the second flat plate, 41 is the screw rod, and 42 is the set screw rod;

31 to 35 are the raw materials for each layer of the membrane electrode: 31 is the anode diffusion layer in contact with the first flat plate 11, 35 is the cathode diffusion layer in contact with the second flat plate 12, and 32 is the anode diffusion layer covering the anode diffusion layer 31. The anode catalyst layer on the surface, 34 is the cathode catalyst layer covering the surface of the cathode diffusion layer 35, and 33 is the proton exchange membrane layer in contact with the anode catalyst layer 32 and the cathode catalyst layer 34 respectively.

In the present invention, there is no special limitation on the raw materials of the above-mentioned layers, and those commonly used in the field can be used. Specifically, the anode diffusion layer can be carbon paper or carbon cloth; the cathode diffusion layer can be carbon paper or carbon cloth, preferably using two consistent diffusion layers;

The anode diffusion layer and the anode catalyst layer covering its surface form a catalyst anode layer, which can be prepared according to methods known to those skilled in the art, specifically: spraying an anode catalyst on the surface of the anode diffusion layer 31 . Wherein, the anode catalyst of the anode catalyst layer is preferably a PtRu black catalyst or a PtRu/C catalyst, and the spraying amount is preferably 2 mg/cm ² -5 mg/cm ² .

Correspondingly, the cathode diffusion layer and the cathode catalyst layer covering its surface form a catalyst cathode layer, which can be prepared according to methods well known to those skilled in the art, specifically: spraying a cathode catalyst on the surface of the cathode diffusion layer 35 . Wherein, the cathode catalyst of the cathode catalyst layer is a Pt black catalyst or a Pt/C catalyst, and the spraying amount is preferably 2 mg/cm ² -5 mg/cm ² .

In the present invention, the process of using the above-mentioned clamp to prepare the membrane electrode of the proton exchange membrane fuel cell is specifically:

The anode diffusion layer 31, the anode catalyst layer 32, the proton exchange membrane layer 33, the cathode catalyst layer 34, and the cathode diffusion layer 35 are sequentially stacked between the first flat plate 11 and the second flat plate 12;

Then tighten screw rod 41 and set screw rod 42;

Then put the above-mentioned fixture with the raw materials of each layer of the membrane electrode on the molding machine and heat it under the condition of no external pressure, take it out after heating, remove the first plate and the second plate after cooling, and obtain the membrane electrode of the proton exchange membrane fuel cell .

The invention provides a method for preparing a membrane electrode of a proton exchange membrane fuel cell, comprising:

The anode diffusion layer, the anode catalyst layer, the proton exchange membrane layer, the cathode catalyst layer, and the cathode diffusion layer are sequentially placed between the first flat plate and the second flat plate placed in parallel, and the first flat plate and the second flat plate are provided with through hole, the screw rod connects the first plate and the second plate through the through hole;

The torque of the screw rod is set to 0.5N·m～5N·m, the first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole to complete the fixation;

The fixed first plate, the second plate, and the anode diffusion layer, anode catalyst layer, proton exchange membrane layer, cathode catalyst layer, and cathode diffusion layer placed between the first plate and the second plate in sequence were placed at 140°C. Heating at ~250° C. for 2 minutes to 30 minutes to obtain a proton exchange membrane fuel cell membrane electrode.

The applicant found that the molding method of the membrane electrode has an important impact on the performance of the electrode: the molding method determines the bonding force between the components of the membrane electrode, whether the gas and liquid transmission channels are smooth, and whether the proton and electron channels are blocked. Therefore, The invention improves the electrochemical performance of the membrane electrode by adjusting the molding method.

In the present invention, firstly, the anode diffusion layer, the anode catalyst layer, the proton exchange membrane layer, the cathode catalyst layer and the cathode diffusion layer are sequentially placed between the first flat plate and the second flat plate placed in parallel, and the first flat plate and the second flat plate are both A through hole is provided through which the screw rod connects the first plate and the second plate. The placement situation can be shown in FIG. 2 .

The first flat plate 11 and the second flat plate 12 are placed in parallel, and the space between the two is a storage area, which can be used to place various layers of raw materials for preparing membrane electrodes such as the anode catalytic layer, proton exchange membrane layer and cathode diffusion layer.

The first flat plate is preferably a steel plate or an alloy aluminum plate. Such a plate has good thermal conductivity, high heat resistance and a small expansion coefficient, which is more beneficial to the preparation of a membrane electrode using the fixture; the second flat plate is preferably a steel plate or an alloy As for the aluminum plate, the plates of the two plates can be the same or different, and the same plate is preferred. In the present invention, there is no special limitation on the areas of the first flat plate and the second flat plate, which may be determined according to the area of the membrane electrode to be prepared.

In the present invention, there is no special limitation on the raw materials of the above-mentioned layers, and those commonly used in the field can be used. Specifically, the anode diffusion layer 31 may be carbon paper or carbon cloth; the cathode diffusion layer 35 may be carbon paper or carbon cloth, and two uniform diffusion layers are preferably used.

The anode diffusion layer 31 and the anode catalyst layer 32 covering its surface form a catalyst anode layer, which can be prepared according to methods well known to those skilled in the art, specifically: spraying an anode catalyst on the surface of the anode diffusion layer 31 . Wherein, the anode catalyst of the anode catalyst layer is preferably a PtRu black catalyst (platinum ruthenium black catalyst) or a PtRu/C catalyst, and the spraying amount is preferably 2 mg/cm ² -5 mg/cm ² .

Correspondingly, the cathode diffusion layer 35 and the cathode catalyst layer 34 covering its surface form a catalyst cathode layer, which can be prepared according to methods well known to those skilled in the art, specifically: spraying a cathode catalyst on the surface of the cathode diffusion layer 35 . Wherein, the cathode catalyst of the cathode catalyst layer is a Pt black catalyst (platinum black catalyst) or a Pt/C catalyst, and the spraying amount is preferably 2 mg/cm ² -5 mg/cm ² .

The proton exchange membrane layer 33 is a commonly used proton exchange membrane in the field, such as Nafion115 membrane or Nafion117 membrane, etc., which is not particularly limited in the present invention.

Both the first plate 11 and the second plate 12 are provided with through holes corresponding to each other, and the screw rod 41 connects them through the through holes. The screw rod 41 can not only connect and fix the first plate 11 and the second plate 12, but also adjust the pressing force between the two plates.

The present invention has no special restrictions on the through holes and screw rods, as long as they can play the above functions, such as hexagon socket screw rods can be used; in order to ensure the pressure of the first flat plate 11 and the second flat plate 12 on the membrane electrode clamped therebetween Uniformly, the first plate preferably has at least four through holes, which are symmetrically distributed at the four corners of the first plate. Correspondingly, the number of screw rods 41 is also preferably four.

After placing each layer of raw materials between the two plates, the present invention sets the torque of the screw rod to 0.5N·m～5N·m, the first plate is provided with a screw hole, and the set screw rod passes through the The screw holes tighten the second flat plate to complete the fixation.

In the present invention, the above-mentioned two flat plates are placed in parallel, the torque of the screw rod is 0.5N·m～5N·m, and a set screw rod is arranged to tighten the position of the two flat plates. Specifically, the functions of the above two flat plates, the screw rod and the set screw rod are:

First, pressure is applied to each layer assembly of the prepared membrane electrode, and two flat plates are placed in parallel to ensure that each layer of the membrane electrode is fully and evenly contacted.

Second, through the adjustment of the torque, there is an appropriate pressing force between the two plates, ensuring that the catalyst anode layer, the proton exchange membrane layer and the catalyst cathode layer are fully contacted, and at the same time, the anode diffusion layer and the cathode diffusion layer, etc. No deformation.

For a membrane electrode with an area of less than 20 cm ² , the torque of the screw is preferably 0.8 N·m to 3 N·m; for a membrane electrode with an area of less than 10 cm ² , preferably 4 cm ² to 10 cm ² , the torque of the screw is preferably It is 0.8N·m～1.3N·m.

Thirdly, in the subsequent heating process, the catalyst anode layer, the proton exchange membrane layer and the catalyst cathode layer are heated and expand. At this time, the relative positions of the two flat plates are fixed, which play a positioning role for the above-mentioned layers. At the same time, due to the expansion of the above-mentioned layers, the flat plate produces a reaction force on the above-mentioned layers, and further pressurizes the above-mentioned layers to promote the adhesion of each layer.

The present invention has no special restrictions on the screw holes and set screw rods, as long as they can play the above-mentioned functions, such as hexagon socket set screw rods can be used; in order to further ensure that the first flat plate 11 and the second flat plate 12 are sandwiched between The membrane electrode has a uniform pressure, and the screw holes of the first flat plate are preferably at least four, symmetrically distributed in the edge area of the first flat plate, and correspondingly, the number of set screw rods 42 is also preferably four .

After the fixation is completed, the present invention places the fixed first flat plate, the second flat plate, and the anode diffusion layer, anode catalytic layer, proton exchange membrane layer, cathode catalytic layer, The cathode diffusion layer is heated at 140° C. to 250° C., and after 2 minutes to 30 minutes, a proton exchange membrane fuel cell membrane electrode is obtained.

The invention adopts a molding machine to heat the fixed flat plate sandwiched with various layers of raw materials, and cooperates to control the heating temperature and heating time to ensure higher bonding strength between the layers of the membrane electrode.

The present invention has no special limitation on the molding machine, and it can be used commonly used in the field, such as a flat molding machine. In the present invention, the controlled heating temperature is 140° C. to 250° C., and the time is 2 minutes to 30 minutes. Wherein, the heating temperature is preferably 180°C-210°C; the heating time is preferably 10min-20min. For example, set the heating temperature to 180°C to 210°C and the time to 10min to 20min; or set the heating temperature to 220°C to 250°C and the time to 3min to 8min.

After heating according to the above method, the present invention takes out the flat plate and the like, cools it to room temperature, and removes the flat plate to obtain the membrane electrode of the proton exchange membrane fuel cell.

After obtaining the membrane electrode of the proton exchange membrane fuel cell, it was installed in a self-breathing methanol fuel cell and operated at room temperature, and the performance of the membrane electrode was tested. The test method is a method well known to those skilled in the art, and the test results show that the membrane electrode prepared by the present invention has excellent discharge performance.

To sum up, the present invention adjusts the molding method of the membrane electrode by using a clamp, which can improve the discharge performance of the membrane electrode and further improve the performance of the fuel cell. Specifically, in the present invention, each layer assembly of the membrane electrode is placed between two parallel flat plates, and the two flat plates are connected and fixed by a screw rod and a set screw rod. In the present invention, under the pressure of the flat plate, each layer of the membrane electrode is fully and evenly contacted; at the same time, the present invention controls the torque and sets the set screw to tighten it, so as to ensure that the flat plate exerts pressure on each layer of the membrane electrode in the heating process. Appropriate pressing force makes it difficult for each layer of the membrane electrode to deform during the molding process, thereby ensuring that the anode diffusion layer and cathode diffusion layer in the prepared membrane electrode have high porosity, and protons, electrons, gases and liquids The patency of transportation and the high bonding strength between layers can prolong the cycle life of the fuel cell and improve the electrochemical performance of the fuel cell. In addition, the present invention also controls the heating temperature and time, and cooperates with the above-mentioned clamp to play a role. Therefore, the present invention can produce a membrane electrode with excellent discharge performance, and the preparation method is simple and easy, without introducing expensive molding equipment, and the cost is low, which is favorable for popularization.

In order to further understand the present invention, the jig for forming the membrane electrode of the proton exchange membrane fuel cell provided by the present invention and the preparation method of the membrane electrode of the proton exchange membrane fuel cell provided by the present invention will be specifically described below in conjunction with examples.

Example 1

Spray-coat 5mg/ ^cm2 of platinum ruthenium black catalyst on a piece of 2cm×7cm anode carbon paper to obtain catalyst anode layer; spray-coat 5mg/ ^cm2 of platinum black catalyst on another piece of 2cm×7cm cathode carbon paper to obtain catalyst Cathode layer; place these two carbon papers on both sides of a 3cm×10cm Nafion115 membrane (purchased from DuPont), the catalysts are respectively in contact with the Nafion115 membrane, and then these membrane electrode assemblies are placed in the fixture shown in Figure 1 Between the first flat plate and the second flat plate, both flat plates are made of steel plates;

The torque of the screw that connects and fixes the two plates is set to 1N·m～1.3N·m, the first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole, complete fixation;

Place the clamps with each assembly of the membrane electrode on a flat plate molding machine, heat at 200°C for 10 minutes, then take out the clamps, cool to 25°C, remove the plate, and obtain the proton exchange membrane fuel battery membrane electrodes.

The membrane electrode was installed in a self-breathing methanol fuel cell, operated at 25°C, and the concentration of methanol solution was 3M, and the discharge performance was tested. The test results are shown in Figure 3. Figure 3 is the voltage and power curves measured by discharging the membrane electrode prepared in Example 1 of the present invention with 3M methanol solution at 25°C. In Figure 3, the abscissa is the discharge current, The main ordinate is the discharge voltage, and the secondary ordinate is the discharge power density. It can be seen from Fig. 3 that the maximum power density of the membrane electrode is between 16mW/cm ² and 18mW/cm ² , and it has good discharge performance.

Example 2

Spray-coat the platinum ruthenium black catalyst of 2mg/ ^cm2 on a piece of 2cm×2cm anode carbon paper to obtain the catalyst anode layer; spray-coat the platinum black catalyst of 2mg/ ^cm2 on another piece of 2cm×2cm cathode carbon paper to obtain the catalyst Cathode layer; place these two carbon papers on both sides of a 3cm×3cm Nafion117 membrane (purchased from DuPont), the catalysts are respectively in contact with the Nafion117 membrane, and then these membrane electrode assemblies are placed in the fixture shown in Figure 1 Between the first flat plate and the second flat plate, both flat plates are made of alloy aluminum plates;

The torque of the screw rod that connects and fixes the two plates is set to 0.8N·m～1N·m, the first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole, complete fixation;

Place the fixed clamps with the membrane electrode components on a flat plate molding machine, heat at 240°C for 5 minutes, then take out the clamps, cool to 25°C, remove the plate, and obtain the proton exchange membrane fuel battery membrane electrodes.

The membrane electrode was installed in a self-breathing methanol fuel cell, operated at 25°C, and the concentration of methanol solution was 3M, and the discharge performance was tested. The test results are shown in Figure 4. Figure 4 is the voltage and power curves measured by discharging the membrane electrode prepared in Example 2 of the present invention with a 3M methanol solution at 25°C. In Figure 4, the abscissa is the discharge current, The main ordinate is the discharge voltage, and the secondary ordinate is the discharge power density. It can be seen from Fig. 4 that the maximum power density of the membrane electrode is between 16mW/cm ² and 18mW/cm ² , and it has good discharge performance.

Comparative example 1

Spray-coat the platinum ruthenium black catalyst of 3mg/ ^cm2 on a piece of anode carbon paper of 2cm×2cm to obtain the catalyst anode layer; spray-coat the platinum black catalyst of 3mg/ ^cm2 on the cathode carbon paper of another piece of 2cm×2cm to obtain the catalyst Cathode layer; place these two carbon papers on both sides of a 3cm×3cm Nafion117 membrane (purchased from DuPont), the catalysts are respectively in contact with the Nafion115 membrane, and then these membrane electrode assemblies are placed on a flat molding machine for hot pressing Molding is carried out at a temperature of 130° C., a pressure of 0.5 MPa, and a time of 10 minutes. After hot pressing, it is taken out to obtain a proton exchange membrane fuel cell membrane electrode.

The membrane electrode was installed in a self-breathing methanol fuel cell, operated at 25°C, and the concentration of methanol solution was 3M, and the discharge performance was tested. The test results are shown in Figure 5. Figure 5 is the voltage and power curves measured by the membrane electrode prepared in Comparative Example 1 at 25°C with 3M methanol solution. In Figure 5, the abscissa is the discharge current, and the main ordinate is The coordinate is the discharge voltage, and the sub-ordinate is the discharge power density. It can be seen from FIG. 5 that, using the same membrane electrode assembly, the maximum power density of the membrane electrode produced by the traditional hot pressing method is about 11 mW/cm ² .

It can be seen from the above examples and comparative examples that the discharge performance of the membrane electrode prepared in Comparative Example 1 is inferior to that of the membrane electrodes prepared in Examples 1 and 2. Experimental results show that the present invention uses a clamp to adjust the molding method of the membrane electrode, which can improve the discharge performance of the membrane electrode and further improve the performance of the fuel cell.

In addition, the preparation method of the present invention is simple and easy, does not need to introduce expensive molding equipment, and has low cost, which is favorable for popularization.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (1)

1. A preparation method for a proton exchange membrane fuel cell membrane electrode, comprising: Spray-coat 2mg/ ^cm2 platinum ruthenium black catalyst on a piece of 2cm×2cm anode carbon paper to get catalyst anode layer; spray 2mg/ ^cm2 platinum black catalyst on another piece of 2cm×2cm cathode carbon paper to get catalyst cathode layer; these two carbon papers are placed on both sides of a 3cm × 3cm Nafion117 membrane, the catalyst is in contact with the Nafion117 membrane respectively, and then these membrane electrode assemblies are placed between the first flat plate and the second flat plate placed in parallel, The first flat plate and the second flat plate are provided with through holes, and the screw rod is connected to the first flat plate and the second flat plate through the through holes, and the first flat plate and the second flat plate are both made of alloy aluminum plate; The torque of the screw rod is set to 0.8N·m～1N·m, the first plate is provided with a screw hole, and the set screw rod tightens the second plate through the screw hole to complete the fixation; Place the fixed clamps with the membrane electrode components on a flat plate molding machine, heat at 240°C for 5 minutes, then take out the clamps, cool to 25°C, remove the plate, and obtain the proton exchange membrane fuel battery membrane electrodes.