ABSTRACT
In addition to the electrochemical reactions, reactants and biphasic water transport, other mechanisms limiting optimal platinum utilization are charge transfer, thermomechanical stresses, and irreversible materials degradation. For instance, micro-structural degradation leading to the PEMFC components aging is attributed to several complex physicochemical phenomena not yet completely understood: • Dissolution and redistribution of the catalyst: Mainly due
to the high potentials of the cathode electrode [8]. This phenomenon reduces the specific catalyst surface area leading to the loss of the electrochemical activity [9-12];
• Corrosion of the catalyst carbon-support: Carbon is thermodynamically unstable at typical cathode operating conditions. Furthermore, carbon degrades more rapidly during transient startup and shutdown conditions and high humidification levels. Indeed, oxygen permeation locally increases the cathode potentials accelerating the cathode damage [13];
• Loss or decrease of the hydrophobicity: Caused by the chemical degradation of the PTFE [14], which is used to give hydrophobic properties to the CLs as well as to the gas diffusion layers (GDLs) and the micro porous layers (MPLs). This affects the water management in the cell and thus the electrochemical performance;
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