Mitigating Electronic Conduction in Ceria_Based Electrolytes via External Structure Design

Abstract

Abstract Doped ceria electrolytes are the state of the art low_temperature solid oxide electrolytes because of their high ionic conductivity and good material compatibility. However, cerium tends to reduce once exposed to reducing environments, leading to an increase in electronic conduction and a decrease in efficiency. Here, the leakage current is mitigated in ceria_based electrolytes by controlling the defect chemistry through an engineered cathode side microstructure. This functional layer effectively addresses the problematic electronic conduction issue in ceria_based electrolytes without adding significant ohmic resistance and increases the ionic transference number to over 0.93 in a thin 20 �m ceria_based electrolyte at 500 �C, compared to a of 0.8 for an unmodified one. Based on this design, solid oxide fuel cells (SOFCs) are further demonstrated with the remarkable peak power density of 550 mW at 500 �C and excellent stability for over 2000 h. This approach enables a potential breakthrough in the development of ceria_based low_temperature solid oxide electrolytes.