CN114865029A - A kind of proton exchange membrane fuel cell membrane electrode and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of proton exchange membrane fuel cells, and specifically discloses a method for preparing a membrane electrode of a proton exchange membrane fuel cell. The method comprises mixing a carbon-supported platinum catalyst with a perfluorosulfonic acid resin solution, and using isopropanol as The solvent is prepared into a mixed emulsion, the mixed emulsion is printed on the surface of the porous layer of the anode diffusion layer on a screen printer, dried, and the mixed emulsion is printed on the surface of the cathode surface of the electrolyte membrane on a screen printer, dried Dry, contact the anode surface of the electrolyte membrane with the anode catalytic layer surface of the anode diffusion layer, contact the cathode catalytic layer surface of the electrolyte membrane with the porous layer surface of the cathode diffusion layer, and press the three together on a hot press , forming a membrane electrode. The invention realizes that the anode catalytic layer and the cathode catalytic layer are respectively attached to the anode diffusion layer and the electrolyte membrane through the screen printing technology, which simplifies the operation difficulty, the equipment cost is low, the catalyst loss is small, and the operation is flexible.

Description

A kind of proton exchange membrane fuel cell membrane electrode and preparation method thereof

technical field

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

Background technique

The proton exchange membrane fuel cell uses hydrogen as the fuel and air as the oxidant, and directly converts the chemical energy in the fuel and the oxidant into electrical energy through an electrochemical reaction, which is not limited by the Carnot cycle and has high energy conversion efficiency. At the same time, the product of the reaction is water, which can be directly discharged and is environmentally friendly. The proton exchange membrane fuel cell power generation system consists of multiple subsystems and components. Among them, the membrane electrode is its core component and is the place of electrochemical reaction.

The membrane electrode is usually composed of an anode, an electrolyte membrane and a cathode, wherein the electrolyte membrane is in close contact with the anode and the cathode. The anode is composed of an anode diffusion layer and an anode catalytic layer, and the cathode is composed of a cathode diffusion layer and a cathode catalytic layer. The catalytic layer is on the side close to the electrolyte membrane. The paper layer and the porous layer are composed. The thickness and structure of the carbon paper layer of the cathode and the anode are the same, and the thickness and structure of the porous layer can be the same or different.

At present, the diffusion layer has formed a commercial product. Electrolyte membrane is also a fixed commodity. It is a composite membrane composed of perfluorosulfonic acid resin and porous polytetrafluoroethylene film. The middle is a porous polytetrafluoroethylene film. The cathode and anode surfaces are perfluorosulfonic acid with a certain thickness. Resin, the resin runs through the porous membrane. The cathode resin membrane is thicker than the anode resin membrane. It is divided into different specifications, and the thickness is about 8 microns and about 12 microns. The catalytic layer is composed of a catalyst and a perfluorosulfonic acid resin. Usually, the catalyst and the perfluorosulfonic acid resin solution are prepared into an ink-like uniform mixture, which is coated on the diffusion layer (GDE) or the electrolyte membrane (CCM).

At present, in order to reduce the mass transfer resistance and reduce the thickness of the catalytic layer, the preparation method of the catalytic layer is mainly the CCM method, and the preparation methods of the CCM are mainly the spray method and the slot coating method. The spraying method has simple equipment, intermittent operation, and is suitable for small batch production. The problem is that spraying brings a lot of catalyst waste and increases costs. Slot coating technology is suitable for large-scale operation, automated operation, and quality controllable. The problem is that continuous production is required, and there is a large amount of material waste at shutdown and start-up.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a proton exchange membrane fuel cell membrane electrode and a preparation method thereof, so as to overcome the problems existing in the preparation process of the membrane electrode catalytic layer in the prior art.

In order to solve the above technical problems, the present invention provides a method for preparing a membrane electrode of a proton exchange membrane fuel cell, comprising the following steps:

S1. The carbon-supported platinum catalyst is mixed with the perfluorosulfonic acid resin solution, and isopropanol is used as a solvent to prepare a mixed emulsion;

S2. Cut the anode diffusion layer to a specified size, print the mixed emulsion on the surface of the porous layer of the anode diffusion layer on a screen printer, and dry it to complete the preparation of the anode catalytic layer;

S3. Cut the electrolyte membrane to a specified size, print the mixed emulsion on the surface of the cathode surface of the electrolyte membrane on a screen printer, and dry it to complete the preparation of the cathode catalytic layer;

S4. Contact the anode surface of the electrolyte membrane with the anode catalytic layer surface of the anode diffusion layer, contact the cathode catalytic layer surface of the electrolyte membrane with the porous layer surface of the cathode diffusion layer, and press the three together on a hot press , forming a membrane electrode.

Preferably, in the step S1, the weight ratio of the carbon-supported platinum catalyst to the perfluorosulfonic acid resin solution is 3:1.

Preferably, in the step S1, the viscosity range of the mixed emulsion is 30-80 cP.

Preferably, in the steps S2 and S3, the mesh of the screen printing machine is 80-100 meshes.

Preferably, in the step S2, the thickness of the anode catalyst layer is 5-10 microns.

Preferably, in the steps S2 and S3, the drying temperature is 50-60° C., and the drying time is 3-5 minutes.

Preferably, in the step S3, the thickness of the cathode catalytic layer is 15-25 microns.

Preferably, in the step S4, the protective supporting polyester film on the anode surface of the electrolyte membrane is first peeled off, and then the anode surface of the electrolyte membrane is brought into contact with the surface of the anode catalytic layer of the anode diffusion layer.

Preferably, in the step S4, the hot pressing temperature of the hot pressing machine is 110-130° C., and the hot pressing pressure is 1.5-3 MPa.

The present invention also provides a proton exchange membrane fuel cell membrane electrode, which is made by the method for preparing the proton exchange membrane fuel cell membrane electrode.

The proton exchange membrane fuel cell membrane electrode of the present invention and its preparation method are based on the different transmission speeds of oxygen in hydrogen and air, and the characteristics of current commercial membrane motor products, and propose a cathode and anode catalyst layers using different support methods, through the wire mesh The printing technology realizes that the anode catalytic layer and the cathode catalytic layer are respectively attached to the anode diffusion layer and the electrolyte membrane, which simplifies the operation difficulty, the equipment cost is low, the catalyst loss is small, and the operation is flexible.

Description of drawings

FIG. 1 is a schematic diagram of a method for preparing a membrane electrode of a proton exchange membrane fuel cell according to an embodiment of the present invention.

In the figure, 1: anode diffusion layer; 2: anode catalytic layer; 3: electrolyte membrane; 4: cathode catalytic layer; 5: cathode diffusion layer.

Detailed ways

The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

As shown in FIG. 1 , the preparation method of the membrane electrode of the proton exchange membrane fuel cell of this embodiment includes the following steps:

S1. Mix the carbon-supported platinum catalyst with the perfluorosulfonic acid resin solution, and the carbon-supported platinum catalyst (Pt/C) and the perfluorosulfonic acid resin solution (Nafion solution) are in a weight ratio of Pt/C:Nafion of 3:1, Using isopropanol as a solvent, it is prepared into a mixed emulsion with a certain viscosity, and the viscosity range is 30-80cP.

S2. Cut the anode diffusion layer to a specified size, and print the mixed emulsion on the surface of the porous layer of the anode diffusion layer on a screen printing machine. The mesh of the screen printing machine is 80-100 mesh, drying, and drying temperature It is 50-60℃, and the drying time is 3-5 minutes. The thickness of the catalytic layer can be 5-10 microns according to different catalyst loadings. According to the needs of the catalyst loading, it can be printed one or more times to complete the anode catalytic layer. preparation.

S3. At present, commercial electrolyte membranes have a protective supporting polyester membrane on the anode side. The electrolyte membrane is cut to a specified size, the cathode side of the electrolyte membrane is facing the screen direction, and the polyprotective supporting ester membrane side is facing the screen printing machine table. The protective supporting polyester membrane on the anode side of the membrane can act as a support to enable the electrolyte membrane to be screen printed on a screen printer, whereas without a protective supporting polyester membrane, the electrolyte membrane is too thin to use a screen printer Perform screen printing, fix the electrolyte membrane, and print the mixed emulsion on the cathode surface of the electrolyte membrane on a screen printing machine. The mesh of the screen printing machine is 80-100 mesh, and the drying temperature is 50-100 mesh The drying time is 3-5 minutes at 60°C. The thickness of the catalytic layer can be 15-25 microns according to different catalyst loadings. According to the needs of the catalyst loading, it can be printed one or more times to complete the preparation of the cathode catalytic layer.

S4. First peel off the protective supporting polyester film on the anode surface of the electrolyte membrane, contact the anode surface of the electrolyte membrane with the surface of the anode catalytic layer of the anode diffusion layer, and connect the surface of the cathode catalytic layer of the electrolyte membrane with the surface of the porous layer of the cathode diffusion layer When they are in contact with each other, the three are hot-pressed together on a hot-pressing machine, the hot-pressing temperature of the hot-pressing machine is 110-130°C, and the hot-pressing pressure is 1.5-3MPa to form a membrane electrode.

The membrane electrode of the proton exchange membrane fuel cell in this embodiment is made by the method for preparing the membrane electrode of the proton exchange membrane fuel cell, as shown in FIG. 1 , which includes: an anode diffusion layer 1 , an anode catalytic layer 2 , and an electrolyte membrane 3. Cathode catalytic layer 4 and cathode diffusion layer 5 .

The proton exchange membrane fuel cell membrane electrode and its preparation method of the present invention are based on the different transmission speeds of oxygen in hydrogen and air, and the characteristics of current commercial membrane motor products, and propose a cathodic and anode catalyst layer using different support methods, through the wire mesh The printing technology realizes that the anode catalytic layer and the cathode catalytic layer are respectively attached to the diffusion layer and the electrolyte membrane, which simplifies the operation difficulty, the equipment cost is low, the catalyst loss is small, and the operation is flexible.

Since the cathode catalytic layer is thicker than the anode catalytic layer, and the electrolyte layer on the cathode side of the electrolyte membrane is also thicker than the dielectric layer on the anode side, directly coating the catalyst on the electrolyte membrane for the cathode can make the cathode diffusion layer and the catalysis firmly combined, and at the same time, the electrochemical reaction is stable. The transfer resistance is mainly concentrated in the cathode, and it is more advantageous to prepare the catalytic layer on the electrolyte membrane; while the anode catalytic layer is thin, the electrolyte layer of the electrolyte membrane is also thin, and it is more conducive to its combination with the electrolyte by attaching the catalytic layer to the diffusion layer.

Because the transfer rate of hydrogen is much higher than that of oxygen, and the anode side is pure hydrogen, and the cathode side is air containing about 20% oxygen. Appropriate reductions in anodic transport speed do not affect the overall electrochemical reaction. In this way, the cathode and anode catalytic layers are prepared by different methods mainly considering the characteristics of cathode and anode reactions and the structure of the electrolyte membrane, so as to simplify the manufacturing process to the greatest extent and make it easy to operate and equipment without affecting the performance of the battery. Less investment, flexible membrane electrode size change.

The embodiments of the present invention are presented for purposes of illustration and description, and are not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use.

Claims (10)

1. a preparation method of proton exchange membrane fuel cell membrane electrode, is characterized in that, comprises the following steps: S1. The carbon-supported platinum catalyst is mixed with the perfluorosulfonic acid resin solution, and isopropanol is used as a solvent to prepare a mixed emulsion; S2. Cut the anode diffusion layer to a specified size, print the mixed emulsion on the surface of the porous layer of the anode diffusion layer on a screen printer, and dry it to complete the preparation of the anode catalytic layer; S3. Cut the electrolyte membrane to a specified size, print the mixed emulsion on the surface of the cathode surface of the electrolyte membrane on a screen printer, and dry it to complete the preparation of the cathode catalytic layer; S4. Contact the anode surface of the electrolyte membrane with the anode catalytic layer surface of the anode diffusion layer, contact the cathode catalytic layer surface of the electrolyte membrane with the porous layer surface of the cathode diffusion layer, and press the three together on a hot press , forming a membrane electrode. 2 . The method for preparing a membrane electrode for a proton exchange membrane fuel cell according to claim 1 , wherein in the step S1 , the weight ratio of the carbon-supported platinum catalyst to the perfluorosulfonic acid resin solution is 3:1. 3 . 3 . The method for preparing a membrane electrode for a proton exchange membrane fuel cell according to claim 1 , wherein, in the step S1 , the viscosity of the mixed emulsion ranges from 30 to 80 cP. 4 . 4 . The method for preparing a membrane electrode of a proton exchange membrane fuel cell according to claim 1 , wherein in the steps S2 and S3 , the mesh of the screen printing machine is 80-100 meshes. 5 . 5 . The method for preparing a membrane electrode for a proton exchange membrane fuel cell according to claim 1 , wherein, in the step S2 , the thickness of the anode catalyst layer is 5-10 μm. 6 . 6 . The method for preparing a membrane electrode of a proton exchange membrane fuel cell according to claim 1 , wherein, in the steps S2 and S3 , the drying temperature is 50-60° C., and the drying time is 3-5 minutes. 7 . 7 . The method for preparing a membrane electrode of a proton exchange membrane fuel cell according to claim 1 , wherein, in the step S3 , the thickness of the cathode catalytic layer is 15-25 μm. 8 . 8 . The method for preparing a membrane electrode for a proton exchange membrane fuel cell according to claim 1 , wherein in the step S4 , the protective supporting polyester film on the anode surface of the electrolyte membrane is first peeled off, and then the anode surface of the electrolyte membrane is peeled off. 9 . The surface is in contact with the anode catalytic layer surface of the anode diffusion layer. 9 . The method for preparing a membrane electrode of a proton exchange membrane fuel cell according to claim 1 , wherein in the step S4 , the hot pressing temperature of the hot press is 110-130° C., and the hot pressing pressure is 1.5-3 MPa. 10 . 10 . A membrane electrode for a proton exchange membrane fuel cell, characterized in that it is made by the method for preparing a membrane electrode for a proton exchange membrane fuel cell according to any one of claims 1 to 9 .

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