abstract
Ce0.5Yb0.5O1.75 was prepared for the first time through high temperature (1600 degrees C for 5 h) solid state reaction, after high energy milling to enhance the mechano-chemical interaction of precursor oxides (CeO2 and Yb2O3). Single phase formation was confirmed by powder X-ray diffraction. Impedance spectroscopy data obtained under wide temperature (300-800 degrees C) and oxygen partial pressure (0.21 to about 10(-25) atm) ranges indicates that this material exhibits predominant oxide-ion conductivity under oxidizing conditions while n-type electronic conductivity prevails at low oxygen partial pressure. The mixed oxide shows modest ionic conductivity (1.1 x 10(-3) S cm(-1) at 800 degrees C) with activation energy of 1.3 eV in the 600-800 degrees C temperature range. When combined with molten carbonates (Li2CO3+Na2CO3, 1:1 molar ratio) to produce composite electrolytes, Ce0.3Yb0.5O1.73 slightly decomposed. However, the composite electrical performance is still acceptable and closely matches the conductivity of similar materials (>0.1 S cm(-1) immediately above 500 degrees C). (C) 2015 Elsevier Ltd. All rights reserved.
keywords
LATTICE THERMAL-EXPANSION; ORDER PHASE-TRANSITION; OXIDE FUEL-CELLS; IONIC-CONDUCTIVITY; MIXED OXIDES; SYSTEM; PERFORMANCE; STABILIZATION; GADOLINIA; SM
subject category
Materials Science
authors
Martins, NCT; Rajesh, S; Marques, FMB
our authors
Fernando Manuel Bico Marques
Full professor
Natércia da Conceição Tomé Martins
Junior Researcher
Rajesh Surendran Nair
Post-doc FellowshipGroups
G1 - Porous Materials and Nanosystems
G3 - Electrochemical Materials, Interfaces and Coatings
acknowledgements
Funding from FEDER/ COMPETE and FCT, projects NANOMFC (New-INDIGO/0001/2013) and CICECO-FCOMP-01-0124-FEDER-037271 (PEst-C/CTM/LA0011/2013) is greatly appreciated. S. Rajesh thanks FCT for the postdoctoral grant (SFRH/BPD/76228/2011).