Production method of direct methanol fuel cell dual-catalysis layer electrode membrane electrode

Abstract

The invention provides a preparation method for a double-catalyst layer membrane electrode of a direct methanol fuel cell. The aims of the invention are realized by the following steps: firstly, a non-load inner catalyst layer is directly formed on the surface of a proton exchange membrane, and a CCM membrane electrode is prepared; secondly, an outer catalyst layer, namely a load catalyst outer electrode which contains carbon medium load, is prepared by adoption of GDE method; thirdly, heat pressing of the two electrodes is performed, and the highly efficient double-catalyst layer membrane electrode is obtained. The invention is suitable for the direct methanol fuel cell; the preparation method is simple; the electrode can be mass produced; use amount of catalyst can be effectively reduced; utilization rate of noble metals is improved; the invention is characterized in the double-catalyst layer electrode structure.

Description

(1) Technical field [0001] The invention belongs to the field of fuel cells, and in particular relates to a method for preparing a membrane electrode with double catalyst layer electrodes. (2) Background technology [0002] A fuel cell (FC) is an electrochemical device that directly converts chemical energy into electrical energy through electrode reactions. As a new type of chemical power source, fuel cells are the fourth power generation method after thermal power, hydropower and nuclear power. It has the advantages of diverse fuels, environmental friendliness, low noise, high reliability and convenient maintenance. Direct methanol fuel cell (DMFC, direct methanol fuel cell) is a kind of proton exchange membrane fuel cell. It directly uses methanol water as fuel, can utilize the existing fuel supply system, and has become more attractive than conventional hydrogen fuel cells. DMFC has simple structure, light weight, small size, high specific energy density, convenient m...

AI Technical Summary

Problems solved by technology

The disadvantages of using the traditional method to prepare MEA are: First, due to the difference in expansion coefficient between the catalytic layer and the proton exchange membrane, the proton exchange membrane loses water and shrinks, and is easily separated from the catalytic layer, thereby affecting the stability and service life of the battery; And the immersed Nafion solution is usually difficult to fully penetrate into the catalytic layer and contact the catalyst particles, so the liquid phase resistance in the catalytic layer is relatively large

The disadvantages of this method are: because Nafion will adhere to the surface of PTFE, thereby reducing its hydrophobicity and increasing oxygen diffusion resistance; the platinum particles of electrochemical deposition are usually slightly larger than those prepared by chemical methods, which will also reduce the specific surface area of ​​the electrode; and This method is not conducive to mass production

The disadvantages of this method are: the obtained catalyst particles are larger, the catalyst loading is higher than other methods, and the catalyst may be isolated in a certain area, and the gas mass transfer is not very good. The advantage is that the proton conductivity is very good

It is different from Wei's multi-layer structure. This method does not consider the concentration of the catalyst and the concentration gradient distribution of the porosity in the electrode layer. In the method of rotating pressure, the preparation process of the two catalyst layers is the same. When the membrane electrode is made, the two catalyst layers are easily hot-pressed together and affect each other. The advantages of the catalyst concentration gradient and porosity gradient are not obvious.