Modeling the effect of low carbon conductivity of the cathode catalyst layer on PEM fuel cell performance

Carbon corrosion is a major degradation mechanism in cathode catalyst layers (CCL) of PEM fuel cells. Carbon corrosion causes carbon particles to decrease in size and the ionomer to carbon ratio to increase. One of the consequences of these changes is the reduced electronic conductivity of the carbon phase in CCL. In the present study, the effect of reduced carbon conductivity on the cell performance was investigated through modeling of two experimental case studies of a fresh and a severely degraded CCL. The critical carbon conductivity of CCL, below which the electronic potential loss in a degraded CCL becomes an important contributing loss, is defined. The inter-relations between low carbon conductivity, electronic ohmic loss, and EPSA loss (through Pt/C particles detachment mechanism) are also discussed.