Design and selection of fuel cell gas diffusion layer As an important component of the membrane electrode, the design and selection of the gas diffusion layer should be adapted to local conditions according to factors such as the water management characteristics of the stack, the size of the electrode plate, and the target thickness of the monomer. The gas diffusion layer (GDL) is a type of hydrophobic porous medium material, located between the flow field plate and the catalytic layer, acting as a carrier for water and gas transport, heat transfer, and electron conduction, and provides structural support during assembly and operation. GDL is usually composed of a macroporous substrate (MPS) and a microporous layer (MPL). Among them, the base layer is usually composed of an anisotropic stack of carbon fibers and directly contacts the flow field plate; the microporous layer is formed by mixing carbon-based powder and a water-repellent agent and directly contacts the catalytic layer. Key...