Electrochemical performance of La_0.65Sr_0.35MnO₃ oxygen electrode with alternately infiltrated Sm_0.5Sr_0.5CoO_3-δ and Sm_0.2Ce_0.8O_1.9 nanoparticles for reversible solid oxide cells

La_1-xSr_xMnO₃ is a well-known oxygen electrode for reversible solid oxide cells (RSOCs). However, its poor ionic conductivity limits its performance in redox reaction. In this study, we selected Sm_0.5Sr_0.5CoO_3-δ (SSC) as catalyst and Sm_0.2Ce_0.8O_1.9 (SDC) as ionic conductor and sintering inhibitor to co-modify the La_0.65Sr_0.35MnO₃ (LSM) oxygen electrode through an alternate infiltration method. The infiltration sequence of SSC and SDC showed an influence on the morphology and performance of LSM oxygen electrode, and the influence was gradually weakened with the increasing infiltration time. The polarization resistance of the alternately infiltrated LSM-SSC/SDC electrode was 0.08 Ω cm² at 800 °C in air, which was 3.36% of the LSM electrode (2.38 Ω cm²). The Ni-YSZ/YSZ/LSM-SSC/SDC single cell attained a maximum power density of 1205 mW cm⁻² in SOFC mode at 800 °C, which was 8.73 times more than the cell with LSM electrode. The current density achieved 1620 mA .cm⁻² under 1.5 V at 800 °C in SOEC mode and the H₂ generation rate was 3.47 times of the LSM oxygen electrode.