Strategies for improving oxygen ionic conducting in perovskite oxides and their practical applications

Perovskite oxides with high oxygen ionic conductivity have played major roles in five important devices of significance for clean energy future and automated manufacturing, i.e., solid oxide fuel cell, solid oxide electrolysis cell, oxygen permeable membranes, gas sensors, and oxygen pumps, all of which exhibit different performance requirements and challenges. Although improving the oxygen ion transport within the perovskite lattice serves as the key to increasing the efficiencies of perovskites’ components in these devices, the different criteria, structures, and/or physicochemical properties often become the complicating factors. It is understood that the oxygen ion transport performance of perovskite is mainly determined by the crystal structure, the A/B-site cations and their content, and the oxygen vacancies. This perspective overviews these factors, which can be manipulated to adapt the needs for different devices. Brief discussions are then made on the concepts, status, and outlook of each device together with the strategies for improving the device performance. The summaries and insights provided in this review are anticipated to promote more strategic research and development directions and activities in these important applications.