Energy systems based on fuel cells technology have received increasing attention because, by providing both useful electricity and heat with high efficiency, even at partial loads, can have a strategic role in reduction of greenhouse gas emissions. The high power density, low operating temperature (<100 °C) and rapid start up of a proton exchange membrane fuel cell (PEMFC) make it an emerging alternative to the combustion-based systems for uses in transportation and stationary power generation (residential/commercial). However, the technical issues linked to the syngas feeding (the CO poisoning on the anode catalyst) and the need to assure a high proton conductivity in the whole operating range (heat and water management to avoid the membrane “dry-out” and the cathode flooding), have addressed the research to develop high temperature polymeric membranes which work at temperatures between 120° and 180°C, able to overcome these constraints. In this paper experimental tests carried out on two different commercial MEAs in order to define the most suitable for a laboratory stack, are presented and discussed. The first MEA (MEA1) is based on PBI polymer doped with H3PO4, while the second one (MEA2) uses H3PO4–doped pyridine-based polymer as electrolyte. In particular the experimental activity has been addressed to the impact on cell performance of some working parameters such as the operating temperature, the CO content in the anode gas feeding and the air stoichiometry in the whole operating range. Results have pointed out that the performance of MEA1 are better than those of MEA2 by varying both the operating temperature and the anode gas composition, even if these differences are less significant as the working temperature is lower than 140°C. With referring to the air stoichiometry variation, its impact on MEA2 performance is more important in comparison with that on MEA1. In fact, it is found that the polarization curve of MEA2 obtained for an air stoichiometry equal to 3 is overlapped to that of MEA1 measured for an air stoichiometry of 2.
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