Caracterización in-situ de la estructura cristalina y electrónica de óxidos (La,Sr)(Ti,Co)O3 simulando condiciones de operación como electrodo de celda de combustible simétrica

F. NAPOLITANO; A. SOLDATI; J. GECK; L. SUESCUN; L. ACUÑA; A. FERNANDEZ ZUVICH; D. G. LAMAS

Bahía Blanca

Workshop; Workshop Nacional sobre Celdas de Combustible - CCAR3; 2014

Universidad Nacional del Sur

In this work, a combined synchrotron X-ray diffraction (XPD), Xrayabsorption near edge spectroscopy (XANES) and Extended XrayAbsorption Fine Structure (EXAFS) study of LSTC (0 ≤ y ≤0.5), intended as symmetric solid oxide fuel cells electrode, ispresented. Charge compensation mechanisms were characterizedby room temperature measurements; LSTC has a perovskitepseudocubic structure with an A-site vacancy concentration relatedwith Co doping level. This result seems to be triggered by the factthat Ti remains in a higher formal valence (around 4+) independentof the Co concentrations. On the contrary, Co K-edge XANESspectra shows a dependency with the doping level but this seems tobe related to structural changes. In-situ measurements simulatingSSOFC working environment show that LSTC undergoes arhombohedric to cubic perovskite phase transition with criticaltemperature being dependent of the structural distortion level.