Gas diffusion layer used for fuel cell with proton exchange film, production and application thereof

Abstract

The invention relates to a gas diffusion layer for a proton exchange membrane fuel cell, wherein, the gas diffusion layer is composed of a basal cell layer and a microporous layer, wherein, the total weight percentage content of a hydrophobic agent in the basal cell layer is 1-50 percent; and the hydrophobic nature in the basal cell layer shows the gradient decrease from the side of the microporous layer to the side of a flow field. The preparation steps are as follows: a) the hydrophobic agent is evenly dispersed in a solvent to form slurry; b) the slurry is evenly prepared to the surface of a porous conductive basal cell layer material from one side, the slurry is sunk into the basal cell layer material under the action of gravity and viscous force, thereby realizing the gradient distribution in the basal cell layer; c) the basal cell layer of a gas diffusion electrode is formed by baking for 20-40 minutes at 300-400 DEG C. The gas diffusion layer is applied to hydrogen-oxygen proton exchange membrane fuel cells and direct alcohol fuel cells, as well as cells, electrolytic cells and sensors with the gas diffusion electrode structures. As the gas diffusion layer adopts the gradient hydrophobization, the gas diffusion layer is conductive to the discharge of water which is a cathode product and improves the cell performance.

Description

technical field [0001] The invention relates to a gas diffusion layer for a proton exchange membrane fuel cell. [0002] The present invention also relates to a method for preparing the above-mentioned gas diffusion layer. [0003] The invention also relates to the use of the gas diffusion layers described above. Background technique [0004] Due to its high efficiency and environmental friendliness, proton exchange membrane fuel cells have been paid close attention to by research institutions in various countries in recent years. Its core component, the three-in-one membrane electrode (MEA) assembly, is usually composed of a gas diffusion layer, a catalytic layer, and a proton exchange membrane. The gas diffusion layer is composed of a single base layer or a base layer and a microporous layer, and has multiple functions such as supporting the catalytic layer, collecting current, conducting reaction gas, and discharging product water. The diffusion layer can effectively r...

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Problems solved by technology

The liquid water in the diffusion layer is mainly transmitted by capillary pressure. According to the Kelvin equation, the larger the contact angle, the greater the capillary pressure. However, the traditional impregnation hydrophobization method often makes the two sides of the base layer contain more hydrophobic agents, while the internal hydrophobic The content of the agent is less, that is to say, the capillary pressure on both sides of the base layer is high, and the internal capillary pressure is small, so when the cathodic reaction product water enters the base layer, it is easy to be accumulated inside the base layer, and it is difficult to get rid of it.

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