The Research Of YSZ And YSZ/STO/YSZ Electrolyte Three-Layer Film Structure And Electrical Properties

Solid oxide fuel cell (SOFC) was a friendly low pollution energy conversion device that could convert the energy of a chemical reaction directly into electrical energy. The size of the ionic conductivity in low temperature electrolyte materials is the most main factors that decide the performance of SOFC, In this paper, reducing the thickness of the electrolyte film and building new superlattice electrolyte membrane material to reduce battery operating temperature were studied in detail. Pulsed laser deposition technique on the porous NiO-YSZ anode substrate preparation YSZ film and MgO (110) single-crystal substrates for preparing nanoscale YSZ film and YSZ/STO/YSZ three layer superlattice electrolyte film. Using X-ray diffraction (XRD), scanning electron microscope (SEM) and AC impedance spectroscopy analysis of flim phase structure, surface morphology and electrical properties. The results showed that YSZ thin films on NiO-YSZ anode substrates were polycrystalline cubic fluorite structure with columnar structure at300-500℃, Polycrystalline layers with a preferential (111) orientation. The conductivity of YSZ thin films showed slightly higher performance than bulk YSZ. YSZ thin film deposited on MgO (110) single-crystal substrates, with only (220) diffraction peak, the film surface grains smaller, dense better, activation is0.68eV, the conductivity of thin film higher three orders of magnitude than YSZ bulk material, and with the decrease of thin film thickness, thin film conductivity increased. YSZ/STO/YSZ three layer superlattice electrolyte film, interlayer STO thickness unchanged,62nm thick film on the MgO single-crystal substrate appears YSZ (220) diffraction peak, When thickness reaches more than100nm, thin film appears YSZ (111) diffraction peak, but the STO has grown along the (110) orientation. The electrical conductivity of superlattice electrolyte film curve appears an inflection point at500℃, temperature below500℃, the activation energy of0.64eV, temperature higher than500℃, the activation energy of0.95eV, and the conductivity of superlattice electrolyte film is higher3.3orders of magnitude than YSZ bulk material. From the above results shows that, with the decrease of film thickness and the increase of the film layers, the conductivity of superlattice electrolyte film increased.