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As for the commonly studied LaSrCoFeO (6428), here, a very low area-specific resistance (ASR) was measured for LaSrCoFeO (6482) cathode deposited on a CeGdO (GDC) electrolyte with addition of a thin (1 μm) dense LSCF film deposited by spin coating at the interface between the GDC electrolyte and a 40-μm-thick screen-printed electrode. The ASR ranged from 1 Ω.cm at 500 °C, 0.11 Ω.cm at 625 °C and value as low as 0.03 Ω.cm at 700 °C. Impedance spectra collected in between 500 and 700 °C were carefully studied. They could all be modelled with two R//CPE in series which are likely associated to the oxygen reduction reaction itself (dissociation/adsorption/ionization) at low frequency and to the oxide ion transfer at the electrode/electrolyte interface at high frequency. [ABSTRACT FROM AUTHOR]

$$\hbox {Ba}_{0.85}\hbox {Sr}_{0.15}\hbox {Ti}_{0.9}\hbox {Fe}_{0.1}\hbox {O}_{3}$$ (BSTF) powder has been synthesized by solid-state reaction in aim to develop lead-free semiconductor gas sensors. Thick BSTF films were therefore deposited on alumina substrates coated by silver-palladium (Ag-Pd) bottom electrodes and then sintered at 1100 °C for 2 h. These films were physically and electrically characterized. The dielectric constant, loss tangent and conductivity evolutions were investigated in extended frequency and temperature ranges and compared to results given by a non doped barium titanate thick film. A huge increase of the BSTF conductivity variation, by a factor of 10,000 at low frequency when the temperature ranges from 25 to 500 °C, was observed. This behaviour, associated to a relaxation mechanism governed by the migration of oxygen vacancies, has led to a drastic change of the BSTF conductivity. [ABSTRACT FROM AUTHOR]

Abstract: LSCF (La0.6Sr0.4Co0.8Fe0.2O3) thick and thin films were synthesized by using a Pechini method for Solid Oxide Fuel Cell cathode realization to make symmetrical half-cells. A dense LSCF thin film was deposited by spin coating between porous thick LSCF cathode film and gadolinium-doped ceria electrolyte in ceramic form. Atomic force microscopy and scanning electron microscopy characterizations were carried out on these materials to observe the microstructure and measure the thicknesses of the films. DC measurements on LSCF pellets showed that the conductivity of the material is optimized as higher than 100S/cm at temperatures above 400°C. Electrochemical Impedance Spectroscopy measurements at 700°C have shown that, thanks to the interlayer thin LSCF film, the Area Specific Resistance of the cathode has decreased by 27%. [Copyright &y& Elsevier]