XPS and impedance spectroscopy of Gd doped CeO2 superionic ceramics

Abstract

Ce_0.9Gd_0.1O_1.95 (CGO-10) and Ce_0.8Gd_0.2O_1.9 (CGO-20) ceramics have been sintered by using commercial powders of Fuel Cell Materials company. The powders of different surface area (BET [m²/g]) were used to prepare the ceramics. Elemental compositions of CGO solid electrolytes' surfaces have been investigated in 10^–7 Pa vacuum by X-ray photoelectron spectroscopy and the ratio Ce⁴⁺/Ce³⁺ has been estimated. Electrical parameters of CGO ceramics were investigated in the frequency range from 1 MHz to 1.2 GHz. Temperature-dependant bulk ionic conductivity (σ_b) was found to follow the Arrhenius law. Ionic conductivity of CGO-10 was higher compared to that of CGO-20. The bulk ionic conductivity of CGO-10 ceramics slightly depended on the grain size of initial powder.
Keywords: CeO₂, ceramics, XPS, ionic conductivity
PACS: 61.10.Nz, 66.30.Hs, 81.05.Je, 82.45.Yz