Proton conduction of new brownmillerite type compounds Ba₂(Zn_2/3B'_1/3)₂O₅ (B'= Nb and Ta) and Ba₂(Zn_3/4W_1/4)₂O₅

Abstract

In order to obtain high ionic conducting materials based on perovskite structure for the electrolyte of Solid Oxide Fuel Cells (SOFCs), Ba₂(Zn_2/3B'_1/3)₂O₅ (B'= Nb and Ta) and Ba₂(Zn_3/4W_1/4)₂O₅ systems were synthesized by solid state reaction. Powder X-ray diffraction analysis revealed that the samples with B' = Nb and Ta in Ba₂(Zn_2/3B'_1/3)₂O₅ had a cubic and a hexagonal perovskite-type structures, respectively, and that Ba₂(Zn_3/4W_1/4)₂O₅ had a cubic NaCl structure. These materials exhibited the uptake of large amount of H₂O and the appearance of high proton conductivity.