Effects of protic ionic liquids on the oxygen reduction reaction - a key issue in the development of intermediate-temperature polymer-electrolyte fuel cells

Intermediate-temperature polymer-electrolyte fuel cells (IT-PEFCs), operated at an elevated temperature of approximate to 120 degrees C, would enable simplified system design and a potential increase in fuel cell performance compared to state-of-the-art low-temperature (LT-)PEFCs. As LT-PEFC membranes rely on the presence of water and high-temperature (HT-)PEFCs suffer from sluggish oxygen reduction reaction (ORR) kinetics, alternative materials must be developed. Promising candidates are protic ionic liquids (PILs) immobilized in, e.g., a host polymer. PILs' properties, such as weak ion adsorption, high acidity of the proton-carrying ion, an excess of the anion precursor, and a high oxygen diffusivity and solubility, are favorable for achieving high ORR rates. Concepts proposed in the literature for incorporating PILs into MEA components are presented herein, and their utility for future IT-PEFCs is discussed.

Automated summary

Intermediate-temperature polymer-electrolyte fuel cells (IT-PEFCs) operating at a higher temperature have the potential to simplify system design and improve performance. The incorporation of protic ionic liquids (PILs) in MEA components can promote high rates of oxygen reduction reaction.