Gas diffusion layer, a preparation method therefor, a membrane electrode assembly and a fuel cell

A gas diffusion layer for fuel cells, the gas diffusion layer comprises a gas diffusion layer substrate and a microporous layer slurry applied directly or by screen printing on the gas diffusion layer substrate, wherein an additive containing catechol or pyrocatechol compounds is added into the microporous layer slurry;

• wherein the gas diffusion layer substrate applied with the microporous layer slurry is calcined to decompose and release functional groups of an amino acid structure in the additive to form a microporous layer on the surface of the gas diffusion layer substrate;
• wherein the slurry used in the preparation process of the microporous layer of the gas diffusion layer contains a conductive material, a pore-forming agent, a hydrophobic agent, and a dispersing agent.