Robust ion-transporting ceramic membrane with an internal short circuit for oxygen production

In this work, a novel membrane configuration with an internal short circuit is proposed for air separation based on the fundamental understanding of the working principles of solid oxide fuel cells. The key idea is to use inherently robust ion conducting ceramic membranes to overcome the problem of the low material stability of the existing ceramic membranes under the real application conditions. To experimentally demonstrate this novel design, samarium-doped ceria (SDC) was synthesized and used as the membrane material. Oxygen permeation results clearly demonstrated that one internal short circuit in the membrane was sufficient to enable the membrane to function, thus simplifying the planar membrane design for future scaling up. In addition, the robustness of the membranes was proved by long term exposure to acid gases (CO₂ and CO₂/H₂O) as O₂ fluxes reverted back to their original values of 0.4 ml min^-1 cm^-2 once these acid gases were switched off. Tested under similar conditions, high O₂ flux through conventional perovskite membranes failed, thus clearly indicating the potential adaptability of the novel SDC membrane to real world industrial application.