Stable High Conductivity Ceria/Bismuth Oxide Bilayered Electrolytes

Abstract

We have developed a high conductivity bilayered ceria/bismuth oxide anolyte/electrolyte that uses the po2 gradient to obtain stability at the anolyte‐electrolyte interface and reduced electronic conduction due to the electrolyte region. Results in terms of solid oxide fuel cell (SOFC) performance and stability are presented. These results include a 90 to 160 m V increase in open‐circuit potential, depending on temperature, with the bilayered structure as compared to SOFCs fabricated from a single ceria layer. An open‐circuit potential of >1.0 V was obtained at 500°C with the bilayered structure. This increase in open‐circuit potential is obtained without any measurable increase in cell resistance and is stable for over 1400 h of testing, under both open‐circuit and maximum power conditions. Moreover, SOFCs fabricated from the bilayered structure result in a 33% greater power density as compared to cells with a single ceria electrolyte layer.