Gas diffusion layer of proton exchange membrane fuel cell and preparation method of gas diffusion layer

Abstract

The invention belongs to the technical field of proton exchange membrane fuel cells, and particularly relates to a proton exchange membrane fuel cell gas diffusion layer and a preparation method thereof. The gas diffusion layer comprises a base material and n microporous layers coating the base material, n is an integer not less than 2, the microporous layer close to the base material is marked as the first microporous layer, the microporous layer far away from the base material is marked as the nth microporous layer, the aperture of the first microporous layer is the largest, the aperture of the nth microporous layer is the smallest, and n is an integer not less than 2. The pore diameters of the microporous layers from the first layer to the nth layer are sequentially decreased, the thickness of the first microporous layer is smaller than the sum of the thicknesses of the rest (n-1) microporous layers, and the total thickness of the microporous layers is 10-50 microns. According to the invention, the interface resistance of the microporous layers and the substrate is reduced through a first transition layer, and the hole cross section of the multi-layer microporous layer is a gradient hole, so that the large holes of the substrate are prevented from being directly transited to the small holes of the microporous layers, thereby enhancing the gas transmission and drainage capabilities of the gas diffusion layer and improving the battery performance.

Description

technical field [0001] The invention belongs to the technical field of proton exchange membrane fuel cells, and in particular relates to a gas diffusion layer of a proton exchange membrane fuel cell and a preparation method thereof. Background technique [0002] When the fuel cell generates electricity, the hydrogen oxidation reaction occurs at the anode to generate protons and electrons, and the generated electrons reach the cathode through the external circuit, and the generated protons are transferred to the cathode through the proton exchange membrane, and the cathode oxygen obtains electrons and reacts with the protons to form water. The generated water needs to be discharged quickly through the gas diffusion layer. If the gas diffusion layer cannot discharge the water quickly, it will cause the catalytic layer to be flooded and affect the further progress of the reaction. The gas diffusion layer drains water through holes, and the size of the holes affects the drainage...

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Problems solved by technology

The pore size of the base material is large, and the pore size of the microporous layer is small. The direct transition from small pores to large pores will affect the drainage effect

[0003] In addition, the wettability of the microporous layer slurry and the surface of the substrate will affect the bonding effect of the microporous layer and the substrate. If the wettability of the slurry and the substrate surface is not good, the microporous layer and the substrate surface will increase material interface resistance

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