Computational and Experimental Study on the Combined Sulfur and Chromium Poisoning Mechanism of LSM, LSCF and LNO Cathodes

Abstract

Perovskites (La,Sr)MnO3 (LSM) and (La,Sr)(Co,Fe)O3 (LSCF) phases and Ruddlesden-Popper phase La2NiO4 (LNO) as solid oxide fuel cell (SOFC) cathodes, have been used due to its high efficiency and low emissions. To further understand the long-term degradation mechanism of the LSM, LSCF, and LNO phase in SO2 and Cr vapor gas impurities, they were prepared, sintered, and heat-treated at 800, 900, and 1000 ℃ in the sulfur, chromium, and water vapor-containing atmospheres, respectively. Later, XRD, SEM, and TEM techniques were applied to the samples, and corresponding simulations were made by the CALPHAD approach based on the same experimental conditions to verify the formation of the detrimental secondary phases. Results showed good agreement among the predictions and experiments. More importantly, extensive simulations were conducted under different conditions (temperature, the partial pressure of oxygen, and impurities) to understand the long-term degradation mechanism and optimize the operating conditions.