Structural and electrochemical features of fast oxide ion conductors

New fast oxide ion conductors for low temperature applications (400–600°C) have been proposed during recent years. These materials exhibit structural features rather different from that of the well-known zirconia-based electrolytes. The aim of this paper is to analyse the main structural characteristics of these various classes of materials to propose them as a guideline for designing new oxide ion conductors. The development of efficient low temperature devices also implies association of a fast electrolyte to a very active electrode system which must be able to support oxygen molecule dissociation and recombination at high current densities. The BIMEVOX materials offer the unique opportunity of being able to act both as the electrolyte and the electrodes, overcoming many chemical and mechanical problems. This point will also be discussed.