Modifying La0.5Sr0.5MnO3 with the U element leads to the formation of nanocomposites as a cathode for proton-conducting SOFCs

Abstract

Sr-doped LaMnO3 (LSM) is a conventional cathode material for traditional solid oxide fuel cells (SOFCs), but its application in proton-conducting SOFCs is unsatisfactory due to the lack of catalytic activity of LSM at intermediate temperatures. Various strategies have been employed to optimize LSM performance, but no radiative element has been utilized. In this study, uranium was used to modify LSM. The U-doped LSM (LSMU) was not a pure phase but rather a mixture of LSM and SrUO4. The formation of oxygen vacancy was promoted at the LSM/SrUO4 interface, as indicated by first-principles calculations and experimental studies, potentially enhancing the oxygen reduction reaction (ORR) activity of the material. Using LSMU as the cathode, the proton-conducting SOFC (H–SOFC) reaches a peak power density of 1206 mW cm−2 at 700 °C, significantly greater than the LSM cell, which reached only 522 mW cm−2 under the same testing conditions. In addition, the current LSMU cell demonstrated the highest power output for LSM-based H–SOFCs to date, proving the LSUM to be an effective cathode for H–SOFCs. This study demonstrated a potential method for immobilizing uranium in a perovskite cathode oxide with improved performance for H–SOFCs.