Comprehensive analysis of oxygen transport properties of a BaFe0.7Zr0.2Y0.1O3–δ-based mixed ionic-electronic conductor

Mixed ionic-electronic conductors (MIECs) represent a convenient means for separating oxygen from air, simultaneously combining high efficiency, low energy consumption and an environmentally safe electrochemical process. In the framework of this study, we propose two effective strategies for fabricating MIEC-based membranes: from a materials science viewpoint, a new perovskite-type BaFe0.7Zr0.2Y0.1O3–δ (BFZY) material was prepared as an alternative to Co-free oxides; from the technological viewpoint, the very simple tape-calendaring method was used to obtain a symmetrical-type membrane with a 150 μm-thick dense BFZY layer separating two porous and well-adhered layers of the same composition. According to experimental results, this membrane achieves maximal oxygen fluxes of 0.13- and 0.28-ml min−1 cm−2 at 750 °C and 850 °C, respectively, which are comparable with those obtained for related Fe- and even Co-containing MIEC membranes. A comprehensive analysis of transport properties conformed that bulk oxygen diffusion is a predominant process in the overall permeation process for the BFZY membrane. These findings provide a fresh approach for the rational design of MIEC materials and membrane cells for supporting the oxygen permeation process, including oxygen separation, oxygen production and electrochemical conversion.