High Performances Oxide Ion Conductors with Covalent Framework and Liquid-Like Ionic Network

Abstract

Depending on their structural dimensionality, bismuth-based oxide ion conductors can be classified in three groups : Bi2O3 itself is the prototype of the three- dimensional oxide ion conductors ; the BIMEVOX family, which particularly generated an increasing interest during the last ten years, belongs to the two-dimensional oxide ion conductors while Bi26Mo10O69 and its related phases, with a structure based on [Bi12O14]∞ columns, can be considered as the first example of mono-dimensional bismuth-based oxide ion conductors. The common feature between these three classes of materials is that oxygen diffusion takes place in a very disordered network, exhibiting a liquid-like structure. The mono and two-dimensional oxide ion conductors have a larger stability range in temperature, since their structure is reinforced by a covalent skeleton. The main feature of the different structural characteristics of these groups of materials are presented and discussed.