GDL(gas diffusion layer) is one of the critical components of a fuel cell and its basic functions are to provide channels for diffusion of gas from fluid to catalyst layer and for drain of liquid water from catalyst layer to fluid.In order to meet service conditions

the understanding for structure-performance of GDL is very essential

such as key parameters structure

porosity

hydrophobicity

hydrophilicity

gas permeability

transport properties

water management and their roles.A mathematics model of 1D and two-phase was built for GDL in cathode of proton exchange membrane fuel cell(PEMFC).A direct numerical procedure was applied for combined equations of the model and Leverett's and Fick's laws to analyze the profiles of liquid water saturation and oxygen concentration across the gas diffusion layer.The effect of GDL characteristics

such as porosity

thickness

contact angle and absolute permeability was discussed.The results show that its hydrophobicity is helpful for removal of liquid water.The effect of contact tangle on liquid water saturation and oxygen mass transfer becomes less and GDL porosity and thickness has little effect on liquid water saturation at the hydrophobic condition

but porosity and thickness of GDL play an important role in oxygen transfer.For practical use

both GDL porosity and thickness increase

there is no significant difference for limiting current density. Tafel slope and limiting current density predicted by the model agree well with the experimental observation from literatures.