Quantification Method of Mass Transfer Resistance in Cathode Catalyst Layer in PEFC

The quantification method of mass transfer resistance in the cathode catalyst layer (CCL) should be established in order to appropriately evaluate the cell performance. Lots of PEFC research assumes that any resistances in PEFC are in series to reaction resistance. In this study, oxygen and proton transfer resistances in CCL were quantitatively separated from reaction resistance by applying the model where the through-plane mass- transport resistances were parallel to the reaction resistance. In order to evaluate oxygen and proton transfer resistance, a dimensionless cathode isothermal one-dimensional model was applied. The mass transfer resistance in CCL can be quantitatively evaluated by obtaining the value of five dimensionless moduli derived from mass balance. Polarization curves dependency on the oxygen partial pressure and relative humidity (RH) were measured at the temperature of 80 °C. Reaction rate parameters, effective oxygen diffusion coefficient, effective proton conductivity, and oxygen permeance through the ionomer layer were determined.