Introduction: Mixed ionic–electronic conductors (MIECs) have been and continue to be of interest for strategic applications related to energy conversion and environmental monitoring including batteries, fuel cells, permeation membranes, and sensors. Within solid oxide fuel cells (SOFCs), for instance, nanostructured ionic and electronic conducting materials can increase the electrochemical performance of the cathode and thus could potentially facilitate lower-temperature operation and thereby provide faster start-up times, improved stability, and less complicated thermal management. .
