Switching of the Crystal Structure of the Oxide Ion Conductor Ba3Ti0.9Mo1.1O8.1 with Applied Pressure

Interest in oxide-ion and proton-conducting materials has grown recently due to their application as electrolytes in solid-oxide fuel cells (SOFCs). In order to make SOFCs more economical is highly desirable to move towards lower working temperatures. To reach this goal new electrolyte materials are needed with high oxide ion conductivity at 400 – 600 °C. We have now synthesised a novel phase Ba3Ti0.9Mo1.1O8.1 that exhibits the highest oxide ion conductivity of all hexagonal perovskites at 600 C and has yet to be chemically doped so there is scope for further improvement.

It is hypothesised that increasing the number of interstitial oxide sites will further enhance the oxide ion conductivity. We propose to perform a neutron diffraction on PEARL to see if it’s possible to increase the number of interstitial oxide sites as a function of pressure as has previously been observed in related materials.