Fabrication and characterization of composite YSZ-La_9.33Si₆O₂₆ oxygen-ion conductor

Abstract

To improve the conductivity of Y₂O₃-stabilized ZrO₂ (YSZ) based oxygen-ion conductor, Zr_0.85Y_0.15O_1.925-La_9.33Si₆O₂₆ (YSZ-LSO) composite ceramics with the mass fraction of La_9.33Si₆O₂₆ (LSO) of 15% were prepared by using a modified coprecipitation method. The phases, microstructures and conductivities of the YSZ, LSO and YSZ-LSO were investigated by X-ray diffraction, electron microscopy and complex impedance, respectively. The results show that the as-calcined powder of YSZ-LSO composite has the grain size less than 10 nm, and the as-sintered composite ceramics are composed of YSZ and LSO phases. The conductivity can be enhanced obviously by composite method. At 700 °C, the conductivity of the composite ceramic is 0.125 S/cm, which is one order in magnitude higher than that of the YSZ ceramic and two orders in magnitude higher than that of LSO ceramic. By analyzing the impedance spectra and modulus spectra, the interfacial effect on the conductivity improvement was proposed.

Keywords

oxygen-ion conductor / composite materials / coprecipitation synthesis / conductivity

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