Proton Conduction in Perovskite Solid Electrolyte for Proton Ceramic Fuel Cell Application at Intermediate Temperatures: A Short Review

Proton-conducting ceramics based on perovskite-type oxides have been significantly applied in a wide range of electrochemical devices such as fuel cells, hydrogen sensors, and steam electrolysers. One of the emerging applications of these ceramic proton conductors is as an electrolyte component in a solid oxide fuel cell (SOFC), where the proton is mobilized from the anode to the cathode side via these conductors. The proton (hydrogen ion) diffusion mechanisms and activation energies (Ea) in these materials are heavily influenced by their composition, stoichiometry, and crystal structure. Hence, this review presents and discusses the mechanism of hydrogen ion movement for proton-conducting solid oxide fuel cells or known as proton ceramic fuel cells (PCFCs), based on experimental and modelling data, including the vehicular and the Grotthuss mechanisms. This review will provide a brief understanding of the connection between experimental and modelling evidence for proton mechanisms in perovskite electrolyte materials.