Tailoring Cobalt-Free La0.5Sr0.5FeO3-δ Cathode with a Non-Metal Cation Doping Strategy for High Performance Proton-Conducting Solid Oxide Fuel Cells

A nonmetal doping strategy was exploited for the conventional La0.5Sr0.5FeO3-δ (LSF) cathode, allowing high performance for proton-conducting solid oxide fuel cells (H-SOFCs). Unlike previous studies focusing on the utilization of metal oxides as dopants, phosphorus, which is a nonmetal element, was used as the cation dopant for LSF by partially replacing Fe ions to form the new La0.5Sr0.5Fe0.9P0.1O3-δ (LSFP) compound. The H-SOFC using the LSFP cathode showed a two-fold peak power density as compared to that using the LSF cathode. Both experimental studies and first-principle calculations were used to unveil the mechanisms for the high performance of the LSFP cells.