Solid-oxide fuel cells (SOFCs) and proton ceramic fuel cells (PCFCs) offer a viable option to produce clean energy from sustainable resources, with low emission of pollutants, fuel flexibility and high energy conversion rates. New materials, which exhibit high ionic conductivity (≥ 10 mS cm-1) at intermediate temperatures (&lt; 600 °C), are sought for the next generation of ceramic fuel cells. Such fuel cells will be more cost-effective and have greater longevity. We have recently discovered high oxide ion and proton conductivity at 500 °C in the hexagonal perovskite derivative Ba7Nb4MoO20. In dry conditions, the conductivity of Ba7Nb4MoO20 is purely oxide ionic, with a wide electrolytic window of 10-18 &lt; pO2 &lt; 1 atm at 600 °C. Proton conduction is enabled under a humidified atmosphere, thanks to the dissociative absorption of water and the creation of protonic defects. Ba7Nb4MoO20 exhibits proton conductivity of 4.0 mS cm-1 at 500 °C, comparable to doped cubic barium cerate and zirconate perovskites, alongside excellent chemical and electrical stability making it attractive for practical applications. The results presented here encourage further study of other systems possessing structural characteristics similar to Ba7Nb4MoO20 as possible oxide ion and/or proton conductors. SoftBV is a new software tool that has been recently developed for screening the materials genome of inorganic fast ion conductors. This programme has been used to predict novel oxide ion/proton conductors in the palmierite family of materials. Preliminary results on this new chemical family of ionic conductors will also be presented.

Oxide ion and proton conductivity in hexagonal perovskite derivatives and palmierites

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.