The performance of a H 2 -fed polymer electrolyte fuel cell (PEFC) with an active area of 48 cm 2 was studied by combining information from polarization curves and a spatially resolved current density map. The cell comprised double-serpentine flow fields and was operated under several operating conditions, changing cathode stoichiometry (2 and 4) while keeping constant anode stoichiometry. Experiments were carried out at different relative humidities (0%, 50%, and 100%) for both anode and cathode feeds, revealing that higher cathode stoichiometry and elevated relative humidity lead to more homogeneous current density distributions and improved overall performance, providing deeper insight into water and reactant management within the cell. This combined analysis demonstrates the potential of this method for rationalizing the influence of different operating conditions and flow field designs in local degradation phenomena of large-area PEFCs, and for providing useful inputs for catalyst-layer design, CFD/model's validation, and degradation-oriented operating strategies.
Giacoppo et al. (2026) studied this question.