abstract
A comparative microstructural study between Ni-Ce0.9Gd0.1O1.95 (Ni-CGO) anodes obtained from NiO-CGO nanocomposite powders prepared by in situ one-step synthesis and by mechanical mixture (two-step synthesis) of NiO and CGO powders is reported. The open porosity and microstructure of sintered and reduced pellets were investigated as a function of the citric acid content used as pore forming agent. Nanosized crystallites for the one-step and two-step routes were around 18 nm and 24 nm against 16 nm and 37 nm, for CGO and NiO, respectively. Overall results show that both routes provided suitable microstructures either for anode-support, or for functional anodes for solid oxide fuel cells (SOFCs), with more versatile characteristics in the case of the one-step route. The electrical characterization of selected NiO-CGO samples, carried out between 90 and 260 degrees C by impedance spectroscopy, confirms electrical percolation of both phases in the composites. However, based on combined microstructural and impedance data, it seems clear that the one-step processing route is the best approach to make SOFC anodes with improved performance. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
keywords
OXIDE FUEL-CELLS; ANODE MATERIALS; ELECTRICAL-PROPERTIES; SOFC ANODES; MICROSTRUCTURE; PERFORMANCE; COMPOSITES; BOUNDARY; ELECTROLYTE; FABRICATION
subject category
Materials Science
authors
Macedo, DA; Souza, GL; Cela, B; Paskocimas, CA; Martinelli, AE; Figueiredo, FML; Marques, FMB; Nascimento, RM
our authors
Fernando Manuel Bico Marques
Full professor
Filipe Miguel H Lebre R Figueiredo
Principal Researcheracknowledgements
The authors acknowledge PPGCEM-UFRN, CAPES (PRO-ENGENHARIAS and PDEE program - BEX 6775/10-1), and FCT (Portugal) for their financial support.