resumo
Ceria-based composite electrolytes (50 and 70 vol%) including one mixture of Li and Na carbonates (1:1 molar ratio) were prepared using either pure CeO2 (modest conductor) or Gd-doped ceria (excellent oxide-ion conductor) as ceramic matrix. The composite electrolytes and their phase constituents were tested under pure CO2, air, and H-2 diluted in N-2, at temperatures ranging from 300 to 580 degrees C, to study their electrical performance. Impedance spectroscopy measurements performed under these working conditions were complemented by microstructural characterization. Low temperature (below melting) impedance shows in a clear manner the relevance of the matrix functionality on the performance of these composites, but also reveals additional microstructural and even unusual composite effects. These data were used to test equivalent circuit models derived from the composite constituent properties, and to assess their potential to design composites for target functionalities at higher temperature. (C) 2013 Elsevier Ltd. All rights reserved.
palavras-chave
PERCENT EUTECTIC MIXTURE; DOPED CERIA; CARBON-DIOXIDE; ELECTRICAL-PROPERTIES; IONIC-CONDUCTIVITY; ITSOFC APPLICATIONS; TRANSITION POINTS; SODIUM-CARBONATE; FUEL-CELLS; 973 K
categoria
Electrochemistry
autores
Rondao, AIB; Patricio, SG; Figueiredo, FML; Marques, FMB
nossos autores
Fernando Manuel Bico Marques
Professor Catedrático
Filipe Miguel H Lebre R Figueiredo
Investigador Principal
Sónia Gonçalves Patrício
Investigador AuxiliarGrupos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
G5 - Materiais Biomiméticos, Biológicos e Vivos
Projectos
NANOCELL - Nanocomposite Electrolytes for Intermediate Temperature Fuel Cells (PTDC/CTM/098486/2008)
agradecimentos
Financial support from Project NANOCELL (PTDC/CTM/098486/2008), CICECO (PEst-C/CTM/LA0011/2011), FCT/COMPETE/FEDER (Portugal) is greatly appreciated. S Patricio thanks FCT for the post-doctoral grant (BPD/75943/2011).