Ionic conductivity of the oxide family Bi[Bi12O14][(Mo,M)O4]5 with M=Li, Mg, Al, Si, Ge and V

The structure and electric conductivity of the fast oxide ion conductors Bi13(Mo,M)5O34, i.e. Bi[Bi12O14][(Mo,M)O4]5 with M=Li, Mg, Al, Si, Ge and V were investigated using X-ray powder diffraction experiments and AC impedance spectroscopy. The compounds of this original family are isostructural with Bi13Mo4VO34; they crystallize in the monoclinic system with the space group P2/c. The structures exhibit typical [Bi12O14]n columns developed along [010], surrounded by (Mo,M)O4 tetrahedra packed in layers parallel to (100) and (001), the electrical balance of the network being achieved by Bi atoms at the intersection of these planes. The syntheses, X-ray powder pattern analyses and conductivity measurements are reported; the best anionic conductor of the family is proved to be Bi[Bi12O14][(Mo0.933Al0.067)O4]5 with σ980 K=1.4×10−2 S cm−1.