Our group found that inner strain appears in the fluorite-perovskite dual-phase oxygen-permeable membrane due to the different thermal expansion coefficients (TECs). The fluorite phase with low TECs is slightly stretched and the perovskite phase with high TECs is compressed in dual-phase membranes. Tensile and compressive strains can promote and inhibit the oxygen ionic transport, respectively. The comprehensive results show that the oxygen ionic transport of the dual-phase membrane is significantly limited by the compressive strain of the perovskite phase. The inner strain inhibits chemical expansion of perovskite phase by limiting the redox of B-site cations. Therefore, in view of the vital role of inner strain to the chemical expansion and oxygen transport, it cannot be ignored during the design and mechanism discussion of oxygen permeable membranes.This work has been published in Journal of Membrane Science.

The article links：https://doi.org/10.1016/j.memsci.2021.120142