Chemical stability and oxygen transport properties of La1−xCaxFe1−yByO3−δ (with B = Co, Ni, Mg) perovskite membranes

The mixed conductive perovskite La1−xCaxFeO3−δ (LCF) exhibits high oxygen permeability. For further improvement of the oxygen permeability as well as the chemical stability, this study investigates the impact of the doping elements on the perovskite B-site. The cobalt (Co) doping of the LCF improved both the oxygen diffusion and the oxygen surface exchange. However, the oxygen semi-permeation flux of the Co-doped LCF sample was not stable at high temperatures under the high oxygen partial pressure difference (air/argon). The magnesium (Mg) doping in the B-site significantly improved the chemical stability of the LCF membranes, with the oxygen semi-permeation performances close to those obtained with the Co-doped LCF membranes. Thus, the Mg-doped LCF presented the best compromise between chemical stability and oxygen semi-permeation performance, which is applicable to the oxygen transport membranes or the cathodes in solid oxide fuel cells.