The performance of La_0.6Sr_1.4MnO₄ layered perovskite electrode material for intermediate temperature symmetrical solid oxide fuel cells

A layered perovskite electrode material, La_0.6Sr _1.4MnO_4+δ (LSMO₄), has been studied for intermediate temperature symmetrical solid oxide fuel cells (IT-SSOFCs) on La_0.9Sr_0.1Ga_0.8Mg _0.2O_3-δ (LSGM) electrolyte. The chemical compatibility tests indicate that no reaction occurred between LSMO₄ oxide and LSGM electrolyte at temperature up to 1000 ^°C both in air and 5% H₂. The lower conductivity in 5% H₂ and higher conduction activation energy than those in air would be caused by poorer overlap of both σ and π bonds. DFT + U calculations also show that oxygen vacancies which formed in reducing atmosphere may block the 3D hopping path for electrons or holes through Mn-O-Mn chains. For LSMO ₄ electrode, SEM results indicate that the electrode formed good contact with the electrolyte after being sintered at 900 ^°C for 2 h. At 800 ^°C, the polarization resistance of the LSMO ₄ cathode is about 0.87 Ω cm² in air, while the polarization resistance of the LSMO₄ anode is about 2.07 Ω cm² in 5% H₂. LSMO₄ exhibits better electrochemical activity for oxygen reduction than that for hydrogen oxidation. A cell with LSGM electrolyte, LSMO₄-LSGM mixture as anode and cathode simultaneously displays a maximum power density of 59 mW cm^{- 2} at 800 ^°C.