Nanostructured LnBaCo2O6-d (Ln = Sm, Gd) with layered structure for Intermediate Temperature SOFC cathodes

摘要

We evaluated for the first time the use of nanostructured layered perovskitesof formulae LnBaCo2O6-d with Ln = Sm and Gd (SBCO and GBCO, respetively) asSOFC cathodes, finding promising electrochemical properties in the intermediatetemperature range (~700{\deg}C). The synthesis of these nanomaterials, notreported before, was achieved by using porous templates to confine the chemicalreagents in regions of about 200 nm and 800 nm. The performance ofnanostructured SBCO and GBCO cathodes for the oxygen reduction reaction wasanalyzed in symmetrical cells using Gd2O3-doped CeO2 (GDC) as electrolyte. Forthis purpose, nanostructured SBCO and GBCO cathodes were deposited on bothsides of the electrolyte by a simple thick-film procedure and evaluated byElectrochemical Impedance Spectroscopy technique under different operatingconditions. We found that cathodes synthesized using smaller template poresexhibited better performance. Besides, SBCO cathodes displayed lowerarea-specific resistance than GBCO ones.