Development of La0.6Sr0.4Co0.2Fe0.8O3-δ cathode with an improved stability via La0.8Sr0.2MnO3-film impregnation

Uniform, dense and continuous coatings of La0.8Sr0.2MnO3-delta (LSM) have been successfully deposited on dense/porous La0.6Sr0.4CO0 2Fe0.8O3-delta (LSCF) substrates via a one-step drop-coating process using a water-based solution in order to improve the operating stability of solid oxide fuel cell cathode. The processing conditions were optimized by precise control of the composition of infiltrating solution, including chelating agents (glycine, citric acid and ethylene glycol), surfactants (polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP)) and pH values (5.25, 4.29, 3.01 and 2.09). Ethanol was found to improve the wetting ability of the water-based solution significantly, but unfortunately causing precipitation. The symmetrical and full cells tests demonstrated that both performance and stability of LSCF cathode can be enhanced by surface modification with an optimized LSM film coating, leading to similar to 31% reduction in cathodic polarization resistance and similar to 45% improvement in power density (without observable degradation) for almost 350 h operation at 750 degrees C under a constant voltage of 0.7 V. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.