The role of SiO2 and sintering temperature on the grain boundary properties of Ce0.8Sm0.2O2-delta
authors Perez-Coll, D; Nunez, P; Frade, JR
nationality International
journal JOURNAL OF POWER SOURCES
author keywords Ceria; Silica; Impedance spectroscopy; Grain boundary; Electrolyte
keywords YTTRIA-STABILIZED ZIRCONIA; GADOLINIA-DOPED CERIA; ELECTRICAL-PROPERTIES; IONIC-CONDUCTIVITY; SOLID-SOLUTIONS; HIGH-PURITY; IMPEDANCE SPECTROSCOPY; NANOCRYSTALLINE CERIA; SILICEOUS PHASE; CERAMICS
abstract The solid solution Ce0.8Sm0.2O2-delta (20CSO) was synthesized by freeze-drying precursor procedure. Well-crystallized powders with nanometric grain sizes were obtained after calcining the precursor at 375 degrees C for 4 h. The effect of Si02-addition and sintering temperature on the properties of the bulk and grain boundary processes were studied. For this purpose, 20CSO-SiO2 samples were prepared by the addition of 0.05 or 0.5 mol% SiO2 to Ce0.8Sm0.2O2-delta, in the form of tetraethyl orthosilicate (TEOS). Also, 2 mol% Co was added to some of the precalcined compositions with and without silica-addition. Cobalt free samples were sintered at 1400, 1500 and 1600 degrees C and cobalt-added samples were sintered 1150 degrees C, for 10 h to obtain dense pellets. The electrical behaviour of the bulk was revealed to be nearly independent on sintering temperature and/or on the addition of impurities of SiO2 and Co to the grain boundaries. This was explained by the low solubility of impurities in the grain fluorite structure. However, the grain boundary resistance showed important differences as function of sintering temperature and with the presence of impurities. The analysis of grain boundary properties suggests that segregated impurities affect the microstructure and also segregation of Sm at the space charge layer, thus changing both the specific grain boundary conductivity and microstructural parameters. (C) 2011 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0378-7753
year published 2011
volume 196
issue 20
beginning page 8383
ending page 8390
digital object identifier (doi) 10.1016/j.jpowsour.2011.06.075
web of science category Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary
subject category Chemistry; Electrochemistry; Energy & Fuels; Materials Science
unique article identifier WOS:000294739000028
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journal impact factor 6.945
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