Novel fluorine-doped layered perovskites Ba1.1La0.9InO3.95–0.5xFx: structure, water uptake and ionic conductivity

The development of novel materials potentially suitable for electrochemical devices, whether for hydrogen production (solid oxide electrolysis cells) or for hydrogen utilization as a fuel to generate electricity (solid oxide fuel cells), is a highly relevant. Proton-conducting electrolytes constitute an essential component of these devices. One of known strategies for improving the transport properties of proton-conducting materials is anionic (fluorine) doping. The fluorine doping was applied to proton-conducting layered perovskite for the first time. Novel layered fluorine-doped perovskites Ba 1.1 La 0.9 InO 3.95–0.5 x F x were obtained. The effect of fluorine doping on the structure, water uptake and ionic conductivity has been investigated. Fluorine doping causes the increase in the conductivity values around 0.8 order of magnitude. The most conductive composition is the Ba 1.1 La 0.9 InO 3.9 F 0.1 sample ( x = 0.10). All compositions are characterized by mixed ionic-hole conductivity at dry air. The significant contribution of proton conductivity is registered in wet air atmosphere. The conductivity values at wet Ar and wet air are almost the same at 300 °C which indicates the dominance of ionic (protonic) transport.