Development of mixed ionic and electronic conducting materials for gas separation membranes: A critical overview

Abstract

Coupling simultaneous mixed ionic (i.e. O2−) and electronic conductivity in a single inorganic membrane has been demonstrated as a very promising approach for gas separation applications. This paper discusses the state-of-the-art materials used on mixed ionic and electronic conducting (MIEC) oxides including cubic fluorite, perovskite, spinel, and multi-phase composites and the underlying interface chemistry for capturing and separating CO2, O2 and H2. The applications for MIEC materials for such separations have been reviewed with an emphasis on the corresponding permeation mechanism. Designing novel MIEC materials with an enhanced permeation performance is critical for reducing the operational costs in large-scale applications of membrane modules, while reduction of the associated energy penalties via renewable energy solutions is of great importance in the future for achieving the net zero targets for greenhouse-gas emissions.