Mixed ionic-electronic conducting (MIEC) oxide ceramics for electrochemical applications

Mixed ion-electron conductors (MIECs) are a special class of electroceramic materials that have significant and comparable ionic and electronic conduction. Because of their excellent electrical and electrocatalytic properties, MIECs have been studied for application in many electrochemical devices such as solid oxide fuel cells (SOFCs), batteries, chemical sensors, membranes for gas separation, and membrane reactors. This chapter gives a brief survey of the basis of mixed ionic-electronic conduction and relates the observed electrical and catalytic phenomena to their crystal and defect structure. Finally, a rational selection of recent MIEC materials used in SOFCs, gas separation membranes, and membrane reactor is presented.