Synthesis of Yttria Stabilized Bismuth Oxide by DC Reactive Magnetron Sputtering (RMS) for SOFC Electrolyte

Abstract

In this work, the compound of Bi1.5Y0.5O3 was deposited from two metallic targets, respectively, Bi and Y; for a power fixed on the target of Y, the power on the target of Bi was adjusted in order to obtain the desired composition. The effects of atomic ratio of Bi to Y and annealing temperature on the film morphology and crystal structure were investigated. The X-ray diffraction (XRD) results showed different crystal structure as a function of the Y content in the film after annealing at 500 °C for 2 h. The Bi1.5Y0.5O3 was obtained with the atomic ratio of Bi to Y adjusted to 3.1. An impurity phase (Bi1.55Y0.45O3, Rhombohedral) appears in the cubic Bi1.5Y0.5O3 after annealing at 600 °C. The field-emission scanning electron microscopy (FESEM) result showed that the Bi1.5Y0.5O3 film after annealing at 800 °C for 2 h is denser than the as-deposited film, despite the presence of some holes. The ionic transport properties of Bi1.5Y0.5O3 film was measured by electrochemical impedance spectroscopy (EIS), and the conductance activation energy was obtained on this basis. The synthesized Bi1.5Y0.5O3 film with higher ionic conductivity (0.13 S/cm at 650 °C) is suitable for SOFC electrolyte.