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Item type:Publication, Access status: with files , Electrochemical properties of La₀.₆Sr₀.₄CoO 3 - δ thin films investigated by complementary impedance spectroscopy and isotope exchange depth profiling(Elsevier, 2014-01-22); ; ; ; The oxygen exchange and diffusion properties of La0.6Sr 0.4CoO3 - δ thin films on yttria stabilized zirconia were analyzed by impedance spectroscopy and 18O tracer experiments. The investigations were performed on the same thin film samples and at the same temperature (400 C) in order to get complementary information by the two methods. Electrochemical impedance spectroscopy can reveal resistive and capacitive contributions of such systems, but an exact interpretation of the spectra of complex oxide electrodes is often difficult from impedance data alone. It is shown that additional isotope exchange depth profiling can significantly help interpreting impedance spectra by giving reliable information on the individual contribution and exact location of resistances (surface, electrode bulk, interface). The measurements also allowed quantitative comparison of electrode polarization resistances obtained by different methods.Publicationtype: Journal ArticleScopus© Citations 29 79 153 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Electrical conductivity, thermal expansion and stability of Y- and Al-substituted SrVO3 as prospective SOFC anode materialElectrical conductivity, thermal expansion and redox behavior of Y- and Al-substituted SrVO3 were evaluated for potential use in solid oxide fuel cell anodes. Sr1 - xYxV1 - yAl yO3 - δ (x = 0-0.4, y = 0-0.2) ceramics were prepared by solid state reaction route and sintered in hydrogen-containing atmosphere. Solid solubility limits of yttrium and aluminum cations in SrVO 3 perovskite lattice were found close to ~ 25% of strontium sublattice and 8-10% of vanadium sublattice, respectively. Under reducing conditions, all ceramics exhibit nearly p(O2)-independent metallic-like electrical conductivity slightly decreasing with substitution level. Undoped SrVO3 - δ is characterized with unfavorably high thermal expansion coefficient (TEC = 21.6 × 10- 6 K - 1 at 823-1273 K) impeding thermomechanical compatibility with common solid electrolytes. Substitutions with yttrium and aluminum suppress to some extent oxygen nonstoichiometry variations and thermal expansion decreasing average TEC values down to (14.5-15.1) × 10- 6 K- 1 at 300-1273 K. Substitutions extend also phase stability domain of perovskite phase, enabling processing of Sr(Y)V(Al)O3 - δ electrodes in inert atmosphere with p(O2) ~ 5 × 10- 5 atm. Slow decomposition into V5 +-based phases is observed however at slightly higher oxygen pressure of ~ 10- 4 atm. Oxidative decomposition into Sr2V2O7 and YVO4 phases on heating in air results in significant bulk dimensional changes, contributed by progressive sintering of Sr2V2O7 phase fraction.Publicationtype: Journal Article73