Preparation and electrical properties of gadolinium-doped strontium tungstate electrolyte for SOFC

Abstract

Gadolinium-doped strontium tungstate (Sr[Formula: see text]GdxWO[Formula: see text]) powders were synthesized by the sol–gel auto-combustion method, and their electrical properties were investigated. The phase formation of Sr[Formula: see text]GdxWO[Formula: see text] powders was studied by the X-ray diffraction (XRD) analysis. The characterization of microstructure was carried out on the sintered ceramic discs. Electrochemical impedance spectroscopy (EIS) was used to estimate the electrical properties. The results displayed that these crystalline powders were scheelite-type tetragonal structures and demonstrated higher sinterability. The Sr[Formula: see text]GdxWO[Formula: see text] electrolyte ceramics with a relative density over 95% of the theoretical density were obtained after the sintering process. The electrical conductivities of Sr[Formula: see text]GdxWO[Formula: see text] increased significantly with increasing of doped-Gd[Formula: see text] content and reached [Formula: see text] S[Formula: see text]cm[Formula: see text] at 800∘C, when the doping amount was [Formula: see text]. At last, this study demonstrated that Sr[Formula: see text]GdxWO[Formula: see text] is an effective strategy to optimize middle or low-temperature SOFC.