Preparation And Characterization Of The(SDC/YSZ)_N Superlattice Electrolye

In this paper, SDC/YSZ (Ce0.8Sm0.2O2-δ/ZrO2:8mol%Y2O3) electrolyte bilayer films were deposited by pulsed laser deposition on MgO single wafer. By X-ray diffraction (XRD), scanning electron microscopy morphology (SEM), electrochemical performance testing, explored the influence of annealing temperature on the properties of films. SDC/YSZ electrolyte films were preferential growth along the (111) direction. Increasing the annealing temperature, the crystalline qualities of the films were improved, the intensity of (111) diffraction peak became larger, preferential growth orientation was much clearer, the incorporation between the substrate and films was more closely, the uniformity and density of films were also improved. Epitaxial growth conditions had been improved with the increased of annealing temperature. Thereby obtaining the optimum annealing temperature for good epitaxial growth. The conductivity of SDC/YSZ electrolyte bilayer films were much higher than the conductivity of bulk YSZ, single SDC and single YSZ films.Multilayers epitaxial thin-film heterostructures of 20 mol% samarium-oxide-doped ceria (Ce0.8Sm0.2O2-δ, SDC) and 8 mol% yttria-stabilized zirconia (8YSZ) were grown using pulsed laser deposition (PLD). Five different superlattice (SDC/YSZ)N films were fabricated, keeping the total thickness constant (300 nm), but with a different number of heterointerfaces (between 6 and 40). To remove any potential contribution of the deposition substrate to the total conductivity, the heterostructures were grown on (110)-oriented MgO single-crystallinewafers. As revealed by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) analysis, the samples having excellent structural and transport properties. Electrochemical measurements showed a size-able increase in conductivity with increasing number of SDC/YSZ interfaces. Oxygen ion conductivity greatly increased with an increasing number of layers compared to bulk polycrystalline yttria-stabilized zirconia and samarium-oxide-doped ceria electrolytes. YSZ and SDC both belong to cubic fluorite structure and have similar lattice parameters, the lattice constant of YSZ is 5.14 A, the lattice constant of SDC is 5.41A. Compatible crystal properties, oxygen ion conductivity, and great matching defects, leading to a semi-coherent interface between the ZrO2 and CeO2 layers (as shown in electron diffraction pattern). Therefore, it appears that a combination of interface tensile strain effect and extended defects due to lattice mismatch between the superlattice structures may contribute to the enhancement of oxygen ionic conductivity in this layered oxide system.