Revealing the critical role of low voltage excursions in enhancing PEM fuel cell catalyst degradation by automotive hydrogen/air potential cycling experiments

Trading Off Initial PEM Fuel Cell Performance versus Voltage Cycling Durability for Different Carbon Support Morphologies

“…3) should hold for other voltage cycling ASTs (excluding bulk carbon support corrosion over 1.0 V), one only would need to know how rapidly a new voltage cycling protocol reduces the electrode roughness factor to understand the associated voltage losses (without requiring further electrochemical tests about the state-of-health of the MEA at a given cathode rf). 64 Thus, as shown in Table I, one can extract for each catalyst the maximum achievable cycle number until a specific durability criterion is met; from this, one can define a durability improvement factor with respect to the Vu based catalyst, calculated as the ratio of the maximum achievable cycles for a given catalyst vs that for the Vu based catalyst at the same criterion (CN x /CN Vu ). We have shown that for solid and (accessible) porous carbon supported catalysts, differences in the cathode rf at BoL and in the characteristic trend of the H 2 /air performance vs rf exist, and thus the rf-loss instead of the absolute rf-value at EoL is used for further comparison.…”