A two dimensional mathematical model was developed for the cathode of proton exchange membrane fuel cell with conventional flow field operating with air. The continuity equation

Darcy’s equation for porous medium

conductive equation and the convection-diffusion equation for O2 and water vapor were used in the gas diffuser

and a coupled boundary condition given by Butler-Volmer equation was used at the cathode catalyst layer interface. The current density distribution in the diffuser

the concentration of O2 and water vapor in the diffusion layer

the local current density distribution at the catalyst layer interface were calculated. The mechanism of gas transport in the cathode gas diffuser

the characterization of gaseous species concentration distribution in the cathode of PEMFCs with conventional flow field were studied.