From Electrolyte and Electrode Materials to Large‐Area Protonic Ceramic Fuel Cells: A Review

Abstract Fuel cells can efficiently convert the chemical energy in fuels like hydrogen and methane into electricity and are an important component for the forthcoming hydrogen society. Compared with conventional solid oxide fuel cells (SOFCs) and proton exchange membrane fuel cells (PEMFCs), protonic ceramic fuel cells (PCFCs) using proton conducting solid oxides as the electrolyte operate at intermediate temperature (400–700 °C), enabling the reduction in cost by using inexpensive catalysts and structural materials. In the last couple of decades, the development of electrolyte and electrode materials for PCFCs has seen significant advances, including fabrication of large‐size cells, promoting PCFCs to step out of the lab toward real applications. This review provides a historic overview of the development of proton conducting oxides, summarizes recent progress on the development of electrolyte and electrode materials and large‐size cells, and discusses present problems and challenges ahead.