Oxygen ionic conductivity of NTE materials of cubic Zr 1− x Ln x W 2− y Mo y O 8− x/2 (Ln = Er, Yb)

• Published in: Solid state sciences Vol. 10; no. 8; pp. 1037 - 1041
• Main Authors: Li, Hai-Hua, Xia, Hai-Ting, Jing, Xi-Ping, Zhao, Xin-Hua
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 2008
• Subjects: AC impedance; Ionic conductibility; Solid electrolytes; Thermal contracting; Thermal contracting; Ionic conductibility; Solid electrolytes; AC impedance
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2007.11.006

Cubic Zr 1− x Ln x W 2− y Mo y O 8− x/2 (Ln = Er: x = 0.01, 0.02, 0.03; y = 0; Ln = Yb: x = 0.02, 0.03; y = 0.4) solid solutions, well-known negative thermal expansion (NTE) materials were prepared by using conventional solid state reactions. The morphology and the composition of the fracture surfaces of the ceramic pellets were determined by SEM and EDX technology. The conductance properties of the pellets, such as conductivity and conductance activation energy, were studied by AC impedance spectroscopy and the materials perform clearly oxygen ionic conduction with the conductivity of about 10 −4 S cm −1 at 673 K, a comparable value to that of ceria based solid electrolytes. The substitution of Mo for W enhanced the thermal stability of ZrW 2O 8, so that the conductivity of Zr 0.98Yb 0.02W 1.6Mo 0.4O 7.99 ceramic can be measured up to 873 K, which is about 5.9 × 10 −4 S cm −1. [Display omitted] The temperature dependence of grain conductivities σ b1's of Zr 1− x Er x W 2O 8− x/2 and Zr 0.98Yb 0.02W 1.6Mo 0.4O 7.99 ceramic pellets. The data demonstrate clearly that oxygen ionic conductivities are about 10 −4 S cm −1 at 673 K, which is comparable to that of ceria based solid electrolytes. The Mo substitution in ZrW 2O 8 enhances the thermal stability, so that the conductivity of Zr 0.98Yb 0.02W 1.6Mo 0.4O 7.99 ceramic was measured up to 873 K which is about 5.9 × 10 −4 S cm −1.