Preparation And Electrical Characterization Of The (GDC/YSZ)_N Superlattice Electrolyte

In this thesis, GDC/YSZ (Ce0.9Gd0.1O2-σ/ZrO2 8 mol % Y2O3) electrolyte bilayer films were deposited by pulsed laser deposition (PLD) on Al2O3 single wafer. By scanning electron microscopy morphology (SEM) to observe the microstructure of thin films, it can be seen that with the increase of annealing temperature, the film became more uniform, the incorporation between the substrate and thin film became more closely, the density of thin film also became better, the epitaxial growth of thin films was also optimized. By X-ray diffraction (XRD), it can be seen that with the increase of annealing temperature, the crystallinity of film was optimized, the films were preferential growth along (111) direction, (111) diffraction peak’s intensity gradually improved, had a more pronounced preferential growth orientation. Therefore, through the analysis of the above results, we can know that when the annealing temperature is 850℃, the film had better epitaxial growth. The conductivity of GDC/YSZ electrolyte bilayer films was higher than the conductivity of single-layer YSZ film, single-layer GDC thin film and bulk YSZ.Using pulsed laser deposition (PLD) fabricated(GDC/YSZ)N(Ce0.9Gd0.1O2-δ/ZrO2.8 mol% Y2O3) superlattice electrolyte thin film on Al2O3 single wafer. By adjusting the number of heterointerfaces, but the total thickness was controlled to a constant value (300 nm), then fabricated five different (GDC/YSZ) N superlattice electrolyte film samples (N= 4,6,10,20,30). Al2O3 has the very high chemical stability, very low electronic conductivity and ionic conductivity. As a result, substrate of the Al2O3 single wafer can eliminate the conductivity of the substrate on the total conductivity of the film. According to the scanning electron microscope to observe the microstructure of thin films (SEM) and transmission electron microscope, it can be seen that the density and uniformity of particles on the surface of the (GDC/YSZ) N superlattice electrolyte film was very good, each layer of thin films associativity was closely, and the film epitaxial growth condition was also good, the interface between the layers was clear, showed that there is no diffusion phenomenon in (GDC/YSZ) N superlattice electrolyte. Through analyzing the thin film X-ray diffraction spectrum (XRD) and high-resolution transmission figure (HR-TEM), the results showed that the structure properties and transport properties of (GDC/YSZ) N superlattice electrolyte were excellent. Through research and analysis of its films’ electrochemical performance test, the result showed that with increasing of (GDC/YSZ) N superlattice electrolyte thin films’layers, its conductivity would increase. The oxygen ionic conductivity of (GDC/YSZ) N superlattice electrolyte thin films is larger than YSZ and GDC electrolyte.