Direct spraying method for preparing fuel cell membrane electrode

Abstract

This invention discloses a directly spraying to make fuel cell film electrode method, which mainly provides a film electrode method in which the electrode is unknit, catalyst layer is uniform, no swelling deforming, and the electrode output energy density is high. The method includes the following steps: preprocessing the ion exchange membrane firstly, then fixing it in a film fixing equipment, and then spraying cathodic and anodic catalyst paste onto the two sides of the ion exchange membrane, at last drying under lower temperature in vacuum. This invention is fit for the membrane electrode of the ion exchange membrane preparation filed.

Description

technical field [0001] The invention relates to a method for preparing a fuel cell membrane electrode, in particular to a method for preparing a fuel cell membrane electrode by direct spraying. Background technique [0002] Fuel cell is a device that can directly convert the chemical energy of fuel into electric energy efficiently and cleanly. Its importance has attracted worldwide attention. Fuel cell technology is one of the most critical high-tech technologies today. Proton exchange membrane fuel cell (PEMFC) has become the most adaptable type of fuel cell due to its unique advantages such as quick start, room temperature operation, no electrolyte loss, easy water discharge, long life, and high specific power. It has broad application prospects in the fields of aviation, national defense, etc. as a power source, emergency power source and base battery. [0003] The membrane electrode (membrane and electrode assembly, MEA for short) is the core component of the fuel cell....

AI Technical Summary

Problems solved by technology

The disadvantage of the method is that Nafion can only be dissolved into the catalytic layer by 10 μm, resulting in part of the catalyst not being utilized, and the high temperature treatment also causes part of the catalyst to sinter together, reducing the surface area

In addition, the method is completed under solvent-free conditions, which is beneficial to environmental protection and can save drying time, but the disadvantage of this method is that Pt is easy to form a dense catalytic layer during the sputtering process, which hinders the diffusion of gases and protons. At the same time, its process is complicated, and it has relatively high requirements for instruments and operating techniques, so it is not suitable for large-scale application

The disadvantage of this method is that the amount of Pt used in the deposition method is relatively large, and some ions are deposited at the same time to poison the electrodes. When using arc deposition, the requirements for the instrument are relatively high, and the operation is complicated.

This method reduces the influence of the solvent on the proton exchange membrane, the prepared catalytic layer is relatively thin, and the assembled single cell has a relatively high power density, but its disadvantages lie in the influence of temperature and pressure on the membrane and the adhesion of the catalyst on the membrane. The strength is affected, and during hot pressing, the edge where the film and the transfer medium are in contact is often destroyed due to uneven force

The advantage of described method is that the consumption of catalyzer is greatly reduced, has improved the power density of battery, and its shortcoming is not to use Na + type membrane, which increases the complexity of operation, and high temperature is easy to damage the mechanical strength of the membrane

At the same time, due to TBA + Reacts with ionic groups in the membrane, affects the proton conductivity of the membrane, and is difficult to control

[0009] The application of Chinese Patent Publication No. CN03139647.x discloses a catalyst slurry with low boiling point and low viscosity alcohol as a dispersant and a high boiling point and high viscosity alcohol as a stabilizer by directly coating the surface of the membrane. The method of MEA, described method adopts Na + Type proton conduction exchange membrane, which increases the preparation temperature, increases the integration of the catalyst and the membrane, and soaks Na with high boiling point 1,2-propanediol + The proton-conducting film reduces the influence of swelling phenomenon on MEA, but its disadvantage is that the preparation process of the method is cumbersome, and the use of propylene glycol increases the use of organic solvents, and the film after soaking propylene glycol cannot completely eliminate the swelling phenomenon. The effect of MEA, while it is easy to become brittle during the drying process, affects the mechanical strength of the film

[0010] Jiang Qizhong, Ma Zifeng (Acta Chemical Industry, 2004, 55 (3): 488-492) disclosed a kind of using isopropanol as solvent, directly using H + Type membrane, using a vacuum system to fix the membrane, transfer the catalytic slurry to the proton exchange membrane to prepare MEA, the disadvantage is that the use of a vacuum system to fix the membrane increases the complexity of the operation, and it is difficult to eliminate the swelling of the membrane occur

[0011] After the 1990s, people directly coated the catalyst on the proton exchange membrane to make the membrane electrode assembly of the core component of the proton exchange membrane. Reduce the thickness of the catalytic layer, improve the mass transfer efficiency, reduce the damage to the membrane by hot pressing and reduce the increase in the internal resistance of the battery, simplify the preparation process, and improve production efficiency, but the disadvantage is that the catalyst slurry is coated on When it is on the proton exchange membrane, it often causes swelling and severe deformation of the membrane

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