CN108321414A - A kind of hydrophobic processing method of fuel cell supporting layer - Google Patents

Abstract

The invention relates to the field of fuel cells, and specifically provides a method for hydrophobic treatment of a fuel cell support layer, which solves the problem that traditional hydrophobic treatment methods will cause hydrophobic agents to easily accumulate on the surface of the support layer and cannot penetrate into the interior of the support layer. Excessive accumulation of water-repellent leads to low electrical conductivity and water-gas mass transfer performance of the support layer. The contact angle distribution of the surface of the support layer obtained by this method is more uniform, and the constant potential oxidation accelerates the decay (1.2V, 0.5MH ₂ SO ₄ ), the experiment shows that after the support layer is subjected to constant potential oxidation for 80 hours, the decrease in the hydrophobicity of the support layer surface is much smaller than that of the support layer in the comparative example, which fully demonstrates that the hydrophobic treatment method proposed by the present invention can significantly improve the support layer. Hydrophobic stability.

Description

Hydrophobic treatment method for fuel cell support layer

technical field

The invention relates to the field of fuel cells, in particular to a hydrophobic treatment method for a fuel cell support layer.

Background technique

Proton exchange membrane fuel cell (PEMFC) core components Membrane electrode assembly (MEA) is composed of gas diffusion layer, catalytic layer and proton exchange membrane. When the battery is running, if the local partial pressure of water vapor is higher than the local saturation partial pressure, water will be produced in the membrane electrode when the proton exchange membrane fuel cell is working, and if the liquid water content in the gas diffusion layer is too high, the liquid water will occur Condensation, the transmission of reactive gases is hindered, thereby affecting the performance of the battery. A typical gas diffusion layer usually consists of a hydrophobic treated support layer and a microporous layer. The hydrophobic treatment of the support layer is usually to place the support layer material in the water repellent (PTFE) emulsion, repeatedly dipping and drying until the loading of PTFE reaches the desired value, and then sintering at 240 ° C to remove the PTFE emulsion. Surfactant, and finally baked at 340°C to melt PTFE to produce hydrophobic network channels. This hydrophobic treatment method will cause the hydrophobic agent PTFE to accumulate on the surface of the support layer and cannot penetrate into the interior of the support layer. The excessive accumulation of surface hydrophobic agent will affect the electrical conductivity and water vapor mass transfer performance of the support layer itself. .

Contents of the invention

In view of the above-mentioned situation, in order to overcome the defects of the prior art, the present invention provides a method for hydrophobic treatment of the fuel cell support layer, the purpose is to solve the problem that the traditional hydrophobic treatment method will cause the hydrophobic agent to easily accumulate on the surface of the support layer, which cannot Penetrating into the interior of the support layer, the excessive accumulation of the surface hydrophobic agent leads to the problems of low electrical conductivity and water vapor mass transfer performance of the support layer.

Considering that immersion treatment in ultrasonic environment can increase the content of hydrophobic agent in the support layer section, but the conventional hydrophobic agent PTFE is easy to agglomerate under the conditions of ultrasonic and organic dispersant, which will affect the hydrophobic treatment effect of the support layer. Hydrophobic agents such as vinylidene fluoride that do not agglomerate in ultrasonic and organic dispersants, from the perspective of improving the hydrophobic stability of the support layer, optimize the hydrophobic treatment process of the support layer, and improve the distribution of the hydrophobic agent on the support layer section content, thereby improving the durability of the support layer.

Specifically, the hydrophobic treatment method provided by the invention comprises the following steps:

1) adding the water-repellent agent into the dispersant, and dispersing uniformly by ultrasonic to obtain a mixed dispersion liquid A with a water-repellent agent mass fraction of 1%-5%;

2) Put the support layer material into the container containing the mixed dispersion A of the above-mentioned hydrophobic agent, perform hydrophobic treatment in an ultrasonic environment, take out the support layer after a few minutes, dry and weigh it;

3) Repeat the above step 2) until the loading of the hydrophobic agent reaches 1%-30% of the mass of the support layer;

4) Put the support layer above in a nitrogen-filled oven, and sinter at a temperature of 160-360° C. for 30-120 minutes to obtain a hydrophobic-treated support layer.

In one embodiment, the dispersant may be one or a mixture of two or more of ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylacetamide.

In one embodiment, the hydrophobic agent is one or two or more of fluorine-containing polymers such as polyvinylidene fluoride, copolymer of tetrafluoroethylene and hexafluoropropylene, polychlorotrifluoroethylene, sulfonic acid resin, etc. mixture.

In one embodiment, the supporting layer is carbon fiber paper or woven cloth.

In one embodiment, the frequency of ultrasonic waves during ultrasonic treatment is 30 kHz-100 kHz.

Compared with the prior art, the distribution of the contact angle on the surface of the support layer is more uniform; the constant potential oxidation accelerates the decay (1.2V, 0.5MH ₂ SO ₄ ), the experiment shows that after the support layer is oxidized by the constant potential for 80 hours, the surface of the support layer The decline in hydrophobicity is much smaller than that of the support layer in the comparative example, which fully demonstrates that the hydrophobic treatment method proposed by the present invention can significantly improve the hydrophobic stability of the support layer.

Description of drawings

The distribution of F elements in the cross-section of the support layer obtained in the embodiment and comparative example of Fig. 1

Detailed ways

The specific implementation manner will be described in further detail below in conjunction with the accompanying drawings and tables.

Embodiment one

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 1% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment two,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 2% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment three,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 3% hydrophobic agent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment four,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 4% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment five,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 5% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment six,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 1% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment seven,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 1% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 20%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment eight,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 1% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 30%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment nine,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 2% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment ten,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 2% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 20%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment eleven,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 2% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 30%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment 12,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 3% hydrophobic agent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment thirteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 3% hydrophobic agent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 20%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment fourteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 3% hydrophobic agent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 30%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment fifteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 4% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of P polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support. Floor.

Embodiment sixteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 4% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment seventeen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 4% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 20%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment eighteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 4% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it (it can be changed to polyvinylidene fluoride, so that the front and back are more consistent), and then soak the carbon paper in the above dispersion liquid for impregnation in an ultrasonic environment, the ultrasonic frequency is 30kHz , took it out after 3 minutes, weighed after drying at 80°C, repeated dipping, drying, and weighing until the load of polyvinylidene fluoride in the carbon paper reached 30%, and finally, the carbon paper treated by the above impregnation method was placed in a In a nitrogen oven, sinter at 340°C for 1 hour to obtain a hydrophobic support layer.

Embodiment nineteen,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 5% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 10%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment twenty,

First, the hydrophobic agent is selected as polyvinylidene fluoride, a certain amount of vinylidene fluoride powder is weighed, and a certain amount of N-methylpyrrolidone and ethanol dispersion is added (the volume ratio of N-methylpyrrolidone and ethanol is 1 :6), ultrasonic dispersion to obtain polyvinylidene fluoride mass fraction is 5% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 20%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

Embodiment 21,

First, select polyvinylidene fluoride as the hydrophobic agent, weigh a certain amount of polyvinylidene fluoride powder, add a certain amount of N-methylpyrrolidone and ethanol dispersion (the volume ratio of N-methylpyrrolidone and ethanol is 1: 6), ultrasonic dispersion to obtain a polyvinylidene fluoride mass fraction of 5% water-repellent dispersion;

Cut the carbon paper into the required size and weigh it. Then, soak the carbon paper in the above dispersion liquid for impregnation treatment in an ultrasonic environment. The ultrasonic frequency is 30kHz. Take it out after 3 minutes, dry it at 80°C and weigh it. Impregnation, drying, and weighing until the loading of polyvinylidene fluoride in the carbon paper reaches 30%. Finally, the carbon paper treated by the above impregnation method is placed in a nitrogen-filled oven and sintered at 340°C for 1 hour to obtain a hydrophobic support layer. .

comparative example

First, 60wt% PTFE emulsion was diluted with deionized water to 1wt% dispersion liquid, and the carbon paper was cut into required size and weighed. Then, using the conventional impregnation method, soak the carbon paper in the above dispersion for several minutes, take it out, dry it at 80°C and weigh it, and repeat the impregnation, drying, and weighing until the loading of PTFE in the carbon paper reaches 10%. Finally, the carbon paper treated by the above method was placed in a nitrogen-filled oven, and sintered at 340°C for 1 hour to obtain a hydrophobic support layer.

In order to analyze the distribution of the water-repellent agent on the cross-section of the support layer, the cross-sections of the support layers prepared in the comparative examples and the examples were subjected to surface scanning of F elements, as shown in FIG. 1 . It can be clearly seen that the distribution of F elements in the cross-section of the support layer prepared by the ultrasonic impregnation method is more uniform, and the mass percentage of the F element in the cross-section of the support layer prepared by the ultrasonic impregnation method is 8.01%, which is significantly higher than that of the conventional impregnation method. Prepared support layer (3.90%).

In addition, the surface of the support layer of the examples and comparative examples was measured using a droplet imaging analyzer (Drop Shape Analyzer 100), and it was found that the distribution of the surface contact angle of the support layer prepared by the embodiment was more uniform; the constant potential oxidation accelerated decay (1.2V , 0.5MH ₂ SO ₄ ) experiments showed that after the support layer was subjected to constant potential oxidation for 80 hours, the decrease in hydrophobicity of the support layer surface in the examples was far less than that of the support layer in the comparative example, which fully illustrates the hydrophobic treatment proposed by the present invention The method can significantly improve the hydrophobic stability of the support layer.

Claims (5)

1. a kind of hydrophobic processing method of fuel cell supporting layer, it is characterised in that：Include the following steps：

1) hydrophober is added in dispersant, it is uniform through ultrasonic disperse, obtain the mixing point that hydrophober mass fraction is 1%-5% Dispersion liquid A；

2) support layer material is put into the container for the mixed dispersion liquid A for filling above-mentioned hydrophober, is carried out under ultrasonic environment Hydrophobic processing takes out supporting layer drying and weighs after several minutes；

3) it repeats the above steps 2) until the loading of hydrophober reaches the 1%-30% of supporting layer quality；

4) above-mentioned support is placed in nitrogen charging baking oven, is sintered at a temperature of 160-360 DEG C and obtains within 30-120 minutes hydrophobic processing The supporting layer crossed.

2. preparation method described in accordance with the claim 1, which is characterized in that the optional ethyl alcohol of dispersant, isopropanol, N- methylpyrroles The mixture of one or both of alkanone, DMAC N,N' dimethyl acetamide or more.

3. preparation method described in accordance with the claim 1, which is characterized in that hydrophober is Kynoar, tetrafluoroethene and six The mixture of one or both of fluoropolymers such as copolymer, polytrifluorochloroethylene, the sulfonate resin of fluoropropene or more.

4. preparation method described in accordance with the claim 1, which is characterized in that the supporting layer is carbon fiber paper or woven cloth.

5. preparation method described in accordance with the claim 1, which is characterized in that the frequency of ultrasonic wave is 30kHz- when supersound process 100kHz。