Novel gas diffusion layer used for fuel cell, preparation and application

Abstract

The invention discloses a gas diffusion layer used for a fuel cell and a preparation method thereof. In a microscopic structure, the double-pore distribution of the diffusion layer is formed by nano-scale hydrophilic micropores and micron-sized hydrophobic macropores; and the structure contributes to that the gas diffusion layer has high-efficiency draining and air guiding functions at the same time. In macrocosmic, the porosity and the aperture of the diffusion layer are in anisotropic distribution on the whole of the diffusion layer; the diffusion layer is in asymmetric conical pore distribution in the direction vertical to the plane of the gas diffusion layer; the porosity and the aperture are decreased gradually from outside to inside; the inside is the side on which an attached catalyst layer is connected with the proton exchange membrane on the diffusion layer when in application; the porosity and the aperture of the diffusion layer are in uniform distribution in the direction parallel to the plane of the gas diffusion layer; and the distribution contributes to improving the mass transfer and the electrical conduction efficiency of the diffusion layer. The invention discloses a preparation technology for preparing micro-porous layers in layers by using pore-forming materials with different types and different grain diameters so as to realize the fuel cell gas diffusion layer of which the porosity and the aperture can be controlled accurately.

Description

technical field [0001] The invention proposes a novel gas diffusion layer for fuel cells and a preparation method. Microscopically, the diffusion layer structure consists of nm-level hydrophilic pores and um-level hydrophobic macropores to form a dual-pore distribution in the diffusion layer. This structure is conducive to realizing the efficient drainage and gas conduction functions of the gas diffusion layer. Macroscopically, the porosity and pore size of the gas diffusion layer present an anisotropic distribution on the whole, and this distribution can improve the mass transfer and conductivity efficiency of the diffusion layer. In the direction perpendicular to the proton exchange membrane, the diffusion layer has an asymmetric cone-shaped pore distribution and in a direction parallel to the proton exchange membrane, it has a uniform porous distribution. The invention discloses a preparation technology of a gas diffusion layer that uses different types and particle sizes ...

AI Technical Summary

Problems solved by technology

It can be seen from the existing literature that the conventional gas diffusion layer preparation method is to simply mix and coat the above-mentioned two components of carbon powder and water-repellent agent on the diffusion layer support such as carbon paper. However, there is still a lack of systematic theoretical analysis on how the three components that constitute the gas diffusion layer should be distributed in space, and how to realize the three functions of water drainage, electrical conduction, and gas transmission.

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