A kind of mea preparation method that noble metal catalyst particles are distributed in gradient

Abstract

The invention relates to an MEA preparation method for realizing gradient distribution of noble metal catalyst granules. The preparation method specifically comprises the following steps of cutting a proton exchange membrane or carbon paper according to needs; preparing noble metal catalyst granular slurry of different concentrations and fully stirring; and coating the proton exchange membrane or carbon paper with the noble metal catalyst granular slurry of different concentrations layer by layer to realize gradient distribution of the noble metal catalyst granules in a thickness direction. Compared with the prior art, the carrying capacity of the noble metal can be lowered, and improvement of the catalyst utilization rate can be facilitated; according to the oxygen concentration gradient distribution characteristic, a gradient distribution active metal catalytic layer is established, so that the usage amount of the noble metal is reduced; less noble metal is adopted in a place with high oxygen concentration while a high-content noble metal is adopted in a place with insufficient oxygen concentration for enabling the oxygen to be fully reacted in a reduction reaction so as to promote an electrochemical reaction; and compared with a spray method, the preparation method provided by the invention can effectively avoid waste and lower cost.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, and in particular relates to a method for preparing an MEA in which noble metal catalyst particles are distributed in gradients. Background technique [0002] A proton exchange membrane fuel cell (hereinafter referred to as a fuel cell) is a power generation device that directly converts chemical energy into electrical energy by using the electrochemical reaction of fuel (hydrogen) and oxidant (usually air) without the Carnot cycle. The membrane electrode assembly (MEA) composed of proton exchange membrane and noble metal catalyst is the core component of the fuel cell. During the working process of the fuel cell, the membrane electrode needs to effectively block the fuel and the oxidant to prevent the fuel from mixing with the oxidant to directly produce chemical reactions. In extreme cases, it may even cause an explosion, or the mutual leakage of fuel and oxidant will cause the battery power...

AI Technical Summary

Problems solved by technology

In addition, the cost of membrane electrode assemblies used in fuel cells is relatively high. If the spraying method is used, the atomized catalyst particles will fly out of the effective spraying area during the production process, resulting in a certain amount of waste

[0007] Membrane electrode assembly preparation, as described in patent CN 200480016800.7, can solve the problem of the concentration distribution of precious metal particles, but using inkjet equipment to deposit the catalyst layer, because the atomized catalyst particles will fly out of the effective spraying area, resulting in certain waste; such as the patent CN03133536.5, the catalytic layer is divided into two-layer structure, using spraying or scraping process, the concentration of the conductive ion polymer is gradually increased from the outside to the inside, and the concentration of the water repellent is gradually decreased from the inside to the outside, but the noble metal catalyst has not been realized. Gradient distribution of particles

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