Oxyanion doping strategies to enhance the ionic conductivity in Ba₂In₂O₅

Abstract

In this paper we report the successful incorporation of phosphate and sulfate groups into the ionic conductor, Ba2In2O5, with the samples analysed through a combination of X-ray diffraction, NMR, TGA, Raman spectroscopy and conductivity measurements. The results show that such oxyanion incorporation leads to a conversion from an ordered brownmillerite-type structure to a disordered perovskite-type, and hence increases the conductivity at temperatures <800 °C. In wet atmospheres, there is evidence for a significant enhancement of the conductivity through a protonic contribution.