Novel KOH-free anion-exchange membrane fuel cell: Performance comparison of alternative anion-exchange ionomers in catalyst ink

Alkaline membrane electrode assemblies (MEAs) were fabricated and tested in 5 cm² single cell configuration. The fuel cell tests were preformed in the absence of any liquid electrolyte, such as KOH. This study shows fuel cell polarization curves for alkaline membrane fuel cell (AMFC) systems that were fabricated with novel anion-exchange ionomers. A comparison of two novel anion-exchange ionomers incorporated into the catalyst ink was achieved by comparing the performance under H₂/O₂ and H₂/air operating conditions. The results presented here indicate that the chemical and physical properties of the recast anion-exchange ionomer that is utilized in AMFC catalyst layers directly influence the obtainable fuel cell performance. It is shown that ionomer materials that are less prone to swelling from hydration and tend to pack closely together in the solid state will result in stronger catalyst-ionomer interfacial interactions. The O₂ transport properties in alkaline MEA cathodes are influenced by the resulting void volume of the electrode as defined by the structure and packing arrangement of the recast ionomer molecules.