Gas diffusion layer for proton exchange membrane fuel cells and preparation method thereof

Abstract

The invention relates to a gas diffusion layer for proton exchange membrane fuel cells; the gas diffusion layer is composed of a carbon nano tube, a carbon fiber and a binder and can be directly used as the gas diffusion layer for the proton exchange membrane fuel cells; the preparation process is as follows: a certain amount of the carbon fiber and the carbon nano tube are weighted according to the proportion and are dispersed uniformly in the solvent; and then a certain amount of the binder is added in the mixture and is mixed uniformly to form slurry; and then the slurry is poured into a filter to carry out vacuumizing filtration, so as to obtain a wet type gas diffusion layer; finally, the prepared wet type gas diffusion layer is placed in a calcining furnace for carrying out heat treatment. The gas diffusion layer in the invention has good electrical conductivity and mass transfer property, can be directly used as the gas diffusion layer for the proton exchange membrane fuel cells, so as to avoid complex treatment process when commodity carbon paper is used; the gas diffusion layer prepared by the method has the advantages of low raw material price, easily-obtaining raw material, simple technology process and controllable thickness / shape, thereby being suitable for mass production.

Description

technical field [0001] The invention relates to a gas diffusion layer for a proton exchange membrane fuel cell and a preparation method thereof. The gas diffusion layer prepared by the above method can be applied in hydrogen-oxygen proton exchange membrane fuel cells, direct alcohol fuel cells, batteries with gas diffusion electrode structures, electrolytic cells and sensors. Background technique [0002] Due to its high theoretical energy density and environmental friendliness, proton exchange membrane fuel cells have attracted close attention from research institutions in various countries in recent years. Its core component, the membrane electrode (MEA), is usually composed of a gas diffusion layer, a catalytic layer, and a proton exchange membrane. The gas diffusion layer has many functions such as supporting the catalytic layer, collecting current, transporting reaction gas and discharging products, and is the core component that affects the performance of the battery....

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Problems solved by technology

[0004] Chinese patent 01132156.3 provides a method for preparing carbon fiber paper materials, using 1% dispersant and overlapping winding between carbon fiber filaments to increase the strength of carbon paper, but there is a phenomenon of filament drop during use, and the internal resistance is also relatively large

CN1417879 provides a carbon fiber paper material for fuel cells and its preparation method. The carbon fiber paper material of the invention uses short high-carbon fibers as the raw material for papermaking slurry. These short fibers of different lengths are overlapped and entangled with each other to form an excellent conductive system. It has evenly distributed pores, which ensures the uniform diffusion of gas, and overcomes the shortcomings of carbon paper resistivity, porosity and uniformity of the traditional electrode gas diffusion layer.

[0006] On the whole, self-made carbon paper generally adopts wet papermaking technology, the equipment occupies a large area, and there is a problem that high-temperature carbonization is required, which not only increases the complexity of preparation, but also requires high equipment requirements

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