Investigation and quantification of irreversible degradations and their sensitivities during the start-up phases of PEMFC By an accelerated emulation approach
Résumé
In automotive application, frequent Start-up/Shut-down (SU/SD) phases of PEMFC system are prone to cause severe degrading conditions. Many studies have been achieved over the past decades to better understand and to mitigate MEA aging and performance decay due to the well-identified reverse current mechanism. Indeed, the H$_2$|Air front during H$_2$ injection at the air-filled anode creates two sub-cells: H$_2$/Air sub-cell operating in Fuel Cell mode and Air/Air sub-cell operating in Electrolysis Cell mode. This second sub-cell is subjected to high potential at cathodic side (about 1.6 V vs RHE), leading to harsh corrosion of both Pt nanoparticles and carbon support within the cathode catalyst layer. Two main mitigating solutions are generally proposed in the literature: (i) development of more stable materials and (ii) improvement of system control. Experimental DOE AST is usually performed only on small single cell to evaluate MEA component durability. Nevertheless, these tests cannot be fully correlated with real automotive operating conditions to predict PEMFC stack lifetime.