Les travaux présentés dans ce mémoire concernent les composants d'assemblages membrane-électrodes (AMEs) pour électrolyseur à membrane échangeuse de protons (PEM – proton exchange membrane) fonctionnant à moyenne température. L'électrolyse de l'eau PEM, alimentée par l'énergie électrique provenant de sources renouvelables, est une voie pour la production efficace et durable d'hydrogène de haute pureté. De nouveaux électrolytes polymère solides (un des principaux éléments de la cellule d'électrolyse) à double conduction, basés sur un réseau semi-interpénétré créé par le polybenzimidazole sulfoné et l'acide polyphosphonique, ont été étudiés. Les membranes perfluorosulfonées (PFSA) à chaîne latérale courte et le composite PFSA-phosphate de zirconium (ZrP) ont également été étudiés. Les matériaux catalytiques de l'anode à base d'oxyde d'iridium ont été préparés par hydrolyse et calcination. L'oxyde d'iridium (IrO2), les oxydes bimétalliques (Ir/Ru) et ternaires (Ir/Ru/Ta) oxydes ont été étudiés par voie électrochimique dans la gamme de températures comprises entre 20 et 120 °C. Les caractérisations physico-chimiques ont confirmé la formation de structures d'oxyde et l'absence de particules de chlorures ou de métal résiduels. On observe une diminution de la tension de cellule, quelle que soit la densité de courant, lorsque la température augmente. Le catalyseur a été déposé sur la membrane, soit par pulvérisation directe ou par transfert en utilisant un support inerte (décalque). Aucune différence significative n'a été observée en appliquant les deux méthodes de dépôt. Les performances s'améliorent lorsque la température augmente pour tous les échantillons. L'assemblage comprenant une membrane de type PFSA, Aquivion®, de masse équivalente 870 meq.g-1 et d'une épaisseur de 120 µm, a montré de meilleures performances pour l'électrolyse de l'eau à 120 °C comparé à l'assemblage comprenant une membrane composite Aquivion® / ZrP, tandis qu'une membrane de type de polybenzimidazole sulfoné à liaison éther, poly-[(1-(4,4'-diphényléther)-5-oxybenzimidazole)-benzimidazole], a montré des performances prometteuses et aucune limitation de transport jusqu'à 2 A.cm-2. Les meilleurs performances ont été observées à 120 °C pour un assemblage préparé par pulvérisation directe de IrO2 sur une membrane Aquivion®; 1,67 V à 2 A.cm-2. / Preparation and investigation of the main components of membrane electrode assemblies (MEAs) for medium temperature proton exchange membrane water electrolysis (PEMWE) are described in this manuscript. Moderate temperature PEMWE, nourished by electrical energy from renewable sources is a practical path to sustainable generation of hydrogen with high purity and efficiency. Novel solid polymer electrolytes (a key component of the electrolysis cell) with double functionality properties, based on highly sulfonated polybenzimidazole creating a semi-interpenetrating network with a polyphosphonic acid, were investigated. A short side chain perfluorosulfonated acid (PFSA) type membrane and PFSA-zirconium phosphate composite membrane were also studied. The anode catalyst materials based on iridium oxide were prepared using the aqueous hydrolysis method followed by calcination. IrO2, some bimetallic (Ir/Ru) and ternary (Ir/Ru/Ta) oxides were electrochemically investigated in a wide range of temperatures (20-120 °C). The physico-chemical characterisation confirmed the formation of oxide structures, absence of residual chloride or metal particles. All catalysts prepared showed decreasing voltage at any given current density with rising the temperature. Catalyst was deposited on the membrane either directly by spray deposition or by decal transfer. No significant difference was observed using both deposition method. The PEMWE performance was increasing with the temperature. The short-side-chain PFSA - Aquivion® ionomer of equivalent weight 870 meq.g-1, of thickness 120 µm, displayed higher water electrolysis performance at 120 °C than a composite membrane of Aquivion® with zirconium phosphate, while a sulfonated ether-linked polybenzimidazole, sulfonated poly-[(1-(4,4'-diphenylether)-5-oxybenzimidazole)-benzimidazole], showed promising performance and no mass transport limitations up to 2 A.cm-2. The lowest cell voltage was observed at 120 °C for an MEA prepared using spray-coating of IrO2 directly on the Aquivion® membrane, 1.67 V at 2 A.cm-2.

The strength and durability of proton exchange membranes for use in fuel cells has received much attention recently due to the increased push for sustainable alternatives to the internal combustion engine. To be viable, these alternatives must have comparable lifetimes and power outputs to the internal combustion engines they replace. Chemical degradation was once viewed as the most common culprit of early fuel cell failure, but as membranes and catalysts improved, mechanical failure became an important factor. As a result, fundamental research on the mechanically-induced failure mechanisms of fuel cell membranes, coupled with development and processing of less expensive membranes, has become an important topic. The use of the blister test geometry, along with digital image correlation of the deformed shape, creates a self-contained analysis tool useful for measuring the biaxial strength of membranes. In this work, blister tests are used to measure biaxial stress and strain for fuel cell membranes subjected to ramped pressure loading to form stress-strain curves that indicate the onset of yielding under biaxial stress conditions. Stress-life curves are developed experimentally for Gore-Selec? series 57 members using data collected under constant pressure conditions. These results are used to predict blister failure under ramped and fatigue loadings. A newly implemented hydrocarbon membrane system is evaluated with constant-pressure-to-leak blister testing. Improved strength following an isothermal hold at 100°C (pretreatment) is shown to occur. Ramped pressure testing indicates that the material after the pretreatment is stiffer and has a higher yield stress than the material before treatment. Morphological and constitutive characterization indicated differences in the materials that are consistent with the improved performance. / Master of Science