Structural stability and conductivity of phase-stabilized cubic bismuth oxides

Bismuth oxide, when stabilized in the face-centered cubic phase by lanthani de doping, has one of the highest oxygen-ion conductivities among all solid oxide electrolytes. We previously reported a time-dependent aging phenomen on in phase-stabilized bismuth oxides that involves ordering of the anion s ublattice, as distinct from a crystallographic phase change, and results in decreased conductivity. In this paper, we report on the structural stabili ty of the disordered lattice in terms of aging, as a function of both dopan t species and dopant concentration. The aging rate decreases with both incr eased dopant cation radius and increased dopant concentration.