Fluorite-based proton conducting oxides: structures, materials and applications

Abstract

Proton conducting oxides have promising potential for application in solid-state electrochemical devices and have seen significant progress in recent years. At present, perovskite-type proton conductors (e.g., Y-doped Ba(Zr, Ce)O₃) attract much attention. However, in fact, those with a fluorite-based structure constitute another interesting category, including doped zirconia and ceria with a fluorite structure, and lanthanide zirconates, stannates, and titanates with a pyrochlore structure. In this work, we focus on the volume transport of protons in fluorite and pyrochlore oxides, summarize the progress on the development of materials and their applications, and discuss the present problems and challenges ahead.