Sulfur poisoning of La(Ni0.6Fe0.4)O3 cathode material for solid oxide fuel cells

Sulfur poisoning of cathode materials is one of the important factors to cause cathode performance degradation resulting in shortening lifetime of SOFC. The sulfur attacks alkali earth components of the rare earth-transition metal perovskite oxides, such as Ba, Ca, Sr, which reacts with SO2 to form sulfates. In this work, the La(Ni0.6Fe0.4)O-3 (LNF) cathode material without alkali earth elements was employed to investigate the sulfur poisoning behavior by flowing 30 ppm SO2 at different temperatures of 500 degrees C-800 degrees C. It was found that SO2 readily reacts with the La2O3 component in LNF to form La2O2SO4 at 700 degrees C and 800 degrees C. The extent of the chemical reaction is temperature dependent. These results confirm that sulfur poisoning also occurs in cathode materials free of alkali earth components. The study prompts the exploration of new materials and new strategies for the developing new cathode materials with high sulfur tolerance. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.