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Several characterization techniques were performed on a proton exchange membrane fuel cell (PEMFC) to relate the performance degradation induced by the membrane-targeted accelerated stress test (AST) to the evolution of electrochemical and physical properties of the electrode. This works investigated the ionomer structure and the proton transport properties. Electron microscopy and small angle neutron scattering analysis provided access to the electrode’s nanoscale structure, the distribution of the platinum particle size, the structure of the 2–3 nm thick ionomer film, as well as the location of the water uptake by the electrode. A newly-developed technique using proton desorption under diluted O2allows to distinguish effectively used active sites for oxygen reduction reaction. Proton transport and dioxygen diffusivity properties were measured using impedance spectroscopy and limiting current technique respectively. The Membrane-AST leads to an increase in the water uptake of the electrode due to a modification of the global structure of the electrode, a reduced platinum surface area, and corrosion of carbon particles. However, it does not alter the ionomer structure. The decrease in performance is partially attributed to the increase in proton resistivity, but mainly due to the limitation of dioxygen transport fostered by the electrode structure modifications.

The marine application of proton exchange membrane fuel cells (PEMFCs) requires special attention due to sea salt aerosols and atmospheric pollutants, susceptible to degrade these systems and induce performance losses. To the best of our knowledge, this study is the first to identify the performance losses of PEMFCs due to sodium chloride (NaCl) pollution similar to that of the marine environment. A 641 h ageing test with a NaCl concentration in air of 120 μg.m‒3was carried out on a five cells stack of 220 cm2. The results reveal a key mechanism for reversible performance loss, namely the deposition of salt particles in the channels and on the surface of the cathode gas diffusion layer (GDL). This can lead to the complete shutdown of a cell. Nonetheless, this contamination did not induce significant irreversible performance losses as the restarts of the stack cause the salt particles to dissolve. An overall degradation rate of 8 μV·h‒1, similar to that of the baseline without NaCl contamination, is observed.

The present work investigates the effects of a salt spray injected into the airflow of Proton Exchange Membrane Fuel Cells (PEMFCs) at various time scales and contamination levels, with the final aim of identifying the appropriate protection for maritime applications. A dedicated experimental setup generates a sodium chloride (NaCl) mist in the cathode airflow to contaminate single cells and stacks. Constant current density tests led to lifetime shortening with partial recovery after cathode rinsing. Then, Membrane Electrode Assemblies (MEAs) post-mortem characterizations revealed that NaCl was present in the cathode gas diffusion layer, and chlorine reached the catalyst layer for high concentrations. Furthermore, chlorides enhanced current collectors and bipolar plates degradation as corrosion products were identified in MEAs and stack effluents. Overall, this study reports that NaCl effects on PEMFCs not only depend on the concentration but also on the MEA type, plate material, and startup/shutdown procedure.

Water production is one of the most interesting characteristic of Proton Exchange Membrane Fuel Cell (PEMFC). However it is also one of the most restricting points, especially for automotive application on winter conditions. In order to further assess the cold operating mechanisms and their effect on durability, specific aging experiments were performed on isothermal single cells. It was found that drying process itself, without start up at sub-zero temperature, can lead to significant degradations. Moreover, 140 freeze/thaw cycles of a fully hydrated MEA have little effect on the FC performances (0.004% cycle-1 at 0.5 A cm-2). Furthermore, successive cold starts with FC starving affect significantly the FC performances. Degradation rates are at least 100 times higher than the one obtained for successive freeze/thaw cycles applied of a non dried cell. This would mean that ice produced during cold start doesn't locate at the same place than the one produced during freeze/thaw cycles.