resumo
Gd-doped ceria (GDC)-based composites, including a eutectic mixture of lithium and sodium carbonate (NLC) as second phase, were prepared using several processing routes, namely chemical synthesis, co-firing of both phases, or impregnation of a presintered porous matrix. LiAlO2-based composites were also prepared and used as reference. The structural, microstructural, and electrical properties (impedance spectroscopy in air, up to 700 degrees C) of these materials were assessed in detail. A limited set of compositions was also used in measurements of total electrical conductivity at different oxygen partial pressures (from 0.21 to <10(-25) atm), in the 600 degrees C to 700 degrees C range. The results obtained confirmed the enormous impact of the processing route on the percolation of the ceramic phase. In the exploited range of operating conditions, GDC-NLC composites prepared by infiltration of molten carbonates within a mechanically robust ceramic matrix exhibit a high total ionic conductivity strongly influenced by the contribution of the molten salt while the ceramic phase is decisive in the appearance of a significant component of electronic conductivity under reducing conditions.
categoria
Energy & Fuels; Nuclear Science & Technology
autores
Grilo, JPF; Macedo, DA; Nascimento, RM; Marques, FMB
nossos autores
Fernando Manuel Bico Marques
Professor Catedrático
João Grilo
Investigador Júnioragradecimentos
Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Grant/Award Number: 205102/2014-0; Fundacao para a Ciencia e a Tecnologia, Grant/Award Numbers: CICECO (UIDB/50011/2020 & UIDP/50011/2020), M-ERA.NET2 (MOCO3-0009/2016)