Travassos, Maria AntóniaRangel, C. M.2012-02-012012-02-012011Travassos, M. A.; Rangel, C. M. Polarity reversal by fuel starvation in PEM Fuel Cells. In: Ciência e Tecnologia dos Materiais, 2011, vol. 23, nº 1-2, p. 25-29http://hdl.handle.net/10400.9/1423In this work, the degradation caused by polarity reversal by fuel starvation of a 16 MEA (membrane-electrode assembly) – low power PEM fuel cell is reported. Measuring of the potential of individual cells, while on load, was found instrumental in the location of affected cells which revealed very low or even negative potential. Ex-situ analysis of MEA, after irreversible degradation by fuel starvation, gave as a result delamination of catalyst layers with impacts on fuel cell performance such as development of flooded areas (in the created gaps by membrane separation) increasing the resistance of reactant transport to the catalyst sites. Striking thickness variations of the anode layers as well as carbon corrosion were found. Also, the proton exchange membrane was found to be affected by fluoride depletion.engPolarity reversalFuel starvationPEM degradationjournal article