Method for preventing pore passages from being flooded with water in catalyst layer of fuel cell

Abstract

The invention discloses a method for preventing pore passages from being flooded with water in the catalyst layer of a fuel cell, and relates to fuel cells. The method comprises the following steps of 1, selecting a hydrophobing agent which does not block the catalyst pore passages according to the pore passage structure of the catalyst and the pore sizes; and 2, adding the hydrophobing agent into the catalyst slurry, thus allowing the hydrophobing agent to uniformly cover the surfaces of the particles to establish a waterproof gas-permeable membrane in the catalyst layer of the fuel cell, and thereby achieving the effect of preventing the pore passages from being flooded with water in the catalyst layer of the fuel cell. By screening the molecular weights and viscosities of the hydrophobing agent, and covering the hydrophobing agent on the surfaces of the catalyst particles, the waterproof gas-permeable membrane is established; and the waterproof gas-permeable membrane can effectively prevent the catalyst micropores from absorbing water and can also be oxygen-permeable, thus active sites in the pore passages are prevented from being flooded with water to the utmost extent, and the activity and stability of the cell are improved. The method is particularly applicable to the three-way M / N / C catalyst based more on micropores, and meanwhile also can be applied to the pores more than 10nm.

Description

technical field [0001] The invention relates to a fuel cell, in particular to a method for preventing channel flooding in the catalyst layer of the fuel cell. Background technique [0002] Fuel cell is a new type of sustainable, efficient and environmentally friendly energy conversion device. Fuel cells convert the chemical energy of fuel directly into electrical energy. The working mechanism of the proton exchange membrane fuel cell is as follows: the fuel (methanol or hydrogen) is oxidized at the anode to produce protons, CO 2 And electrons; electrons flow to the cathode through the external circuit through the load, and the protons also reach the cathode through the proton exchange membrane. In addition, in order to increase the ability of nafion membrane to conduct protons, during the operation of proton exchange membrane fuel cells, it is necessary to humidify the two-pole reaction gas. At the same time, the excess water (methanol) in the anode will also permeate to ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is aimed at the micropores (<10nm) of porous catalysts (such as Pt / C and M / N / C) which are easily blocked by smaller molecules (water, alcohol) resulting in large voltage loss, while the existing Technology is often unable to effectively protect micropores down to this size, providing a way to prevent channel flooding in fuel cell catalytic layers

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