A new class of mono-dimensional bismuth-based oxide anion conductors with a structure based on [Bi12O14]∞ columns

Bi26Mo10O69, i.e. [Bi12O14]2[Bi2Mo10O41] is a pure oxide anion conductor. It can be considered as the first member of the bismuth-based mono-dimensional oxide anion conductors with a skeleton built upon [Bi12O14]∞ columns. In order to modulate its electrical performances, attempts of substitutions in bismuth sites and molybdenum sites were performed. Several dopants have been checked: (i) PbII, CaII, SrII, BaII for bismuth sites, (ii) PV, WVI for molybdenum sites. Six solid solutions, formulated Bi26−xMexMo10O69−0.5x with Me=Pb, Ca, Sr, Ba, Bi26Mo10−xPxO69−0.5x and Bi26Mo10−xWxO69, were characterized. The substitution ratio in bismuth site is systematically limited to two, indicating that the bismuth atoms located in the columns were not affected. In a general way, introduction of oxygen vacancy in the parent compound led to a small decrease of its performances. However the electrical performances of these materials were considerably enhanced by partial substitution for molybdenum with tungsten, giving rise to very attractive properties.