Preparation And Characterization Of The Superlattice Electrolyte Films On SrTiO₃ Buffer Layer

In this paper, thin films of 20 mol% samarium-oxide-doped ceria (Ce0.8Sm0.2O2-δ, SDC) are grown by pulsed laser deposition(PLD) on MgO single-crystal substrates. SrTiO3 (STO) prepared by PLD is used as a buffer layer on the MgO substrates to enable epitaxial grown of the fluorite-structured SDC film. The properties of films were explored by X-ray diffraction (XRD), scanning electron microscopy morphology (SEM). It was known that SDC、SDC/STO electrolyte films were preferential growth along the (111) direction. The STO layer provides a proper crystalline match between SDC and MgO, resulting in highly crystalline, epitaxial SDC films grown well. In conclusion, STO is conducive to the growth of thin films as a buffer layer, and it can reduce the lattice mismatch as well.Multilayer electrolyte thin film of STO, SDC and 8 mol% yttria-stabilized zirconia (8YSZ) were grown using PLD. By SEM, XRD, energy dispersive X-ray spectrometer(EDX), explored the influence of deposition temperature on the properties of films. Can be concluded that 700℃ is advantageous to the film epitaxial growth. At this temperature, the film had cross section, dense and uniform.Fabrication of epitaxial superlattice electrolyte (SDC/YSZ)N thin film on STO-buffered MgO substrate. Four different superlattice (SDC/YSZ)N films were fabricated with a different number of hetero-interfaces (between 8 and 40), keeping the total thickness constant (400 nm). In order to make (SDC/YSZ)N superlattice electrolyte have larger conductivity, so we should ensure the thickness of the SDC is twice of YSZ. The phase, structural, surface morphology and electrical properties of the superlattice electrolyte film STO/(SDC/YSZ)n were characterized through XRD、 SEM、high-resolution transmission electron microscopy(HR-TEM)、energy dispersive spectrometer (EDS) and precision impedance analyzer. The results show that the superlattice electrolyte film STO/(SDC/YSZ)N having excellent structural and transport properties; The thin film did not appear crack no element diffusion at the interfaces, growing uniform, dense and smooth. Electrochemical measurements showed a size-able increase in conductivity with increasing number of SDC/YSZ interfaces. Therefore, it is the ideal of solid fuel battery electrolyte materials at low temperature.