Electrochemical impedance spectroscopy to evaluate the effect of pressure exerted in the hot-pressing stage on the performance of PEMFC

Hot-pressing is one of the most important stages in fabrication of the membrane electrode assembly in a single cell of proton exchange membrane fuel cells (PEMFCs). Electrochemical impedance spectroscopy (EIS) is one of the most powerful nondestructive tools used to evaluate the performance of PEMFCs. This study focused on the pressure exerted during the hot-pressing stage of construction of a single cell. EIS data were analyzed and simulated by an equivalent circuit including elements such as internal impedance (R _s), interfacial impedance (R _if), and reaction impedance (R _rxn). We found that the ohmic resistance derived from I-V diagrams is equal to the sum of R _s and R _if. R _if can be isolated from (R _s+R _if) for use as an evaluation criterion by performing cyclic voltammetry and linear sweep voltammetry. R _if is related to the three-phase interfacial reaction (i.e., catalyst-electrolyte-reactant) that is important in evaluating the effects of hot-pressing pressure on the performance of PEMFCs.