%A LI Chun, FANG Qian-feng, WANG Xian-ping, ZHANG Guo-guang
%T Oxygen-ion diffusion and electrical conduction
of LaMoFeO systems
%0 Journal Article
%D 2008
%J Front. Mater. Sci.
%J Frontiers of Materials Science
%@ 2095-025X
%R 10.1007/s11706-008-0008-6
%P 42-47
%V 2
%N 1
%U {https://journal.hep.com.cn/foms/EN/10.1007/s11706-008-0008-6
%8 2008-03-05
%X Based on the novel oxygen ion conductor La2Mo2O9, a series of Fe-doped samples of La2Mo2-xFexO9-? (x = 0, 0.025, 0.05, 0.1) was prepared by conventional solid-state reaction method. The structure, phase transition, oxygen ion diffusion and electrical conductivity were studied with X-ray diffraction (XRD), differential scanning calorimeter (DSC), direct current (dc) resistivity, and dielectric relaxation (DR) measurements. One DR peak associated with the short-distance diffusion of oxygen vacancies was observed in both temperature and frequency spectra. The activation energy for oxygen ion diffusion in Fe-doped La2Mo2O9 samples was smaller than that in un-doped samples. Fe doping can increase the ionic conductivity of La2Mo2-xFexO9-? samples as well as the ionic transference number in the temperature range from 680°C to 400°C in comparison with the un-doped samples, although the electronic conductivity slightly increases. It is found that because of the small solubility of Fe2O3 in La2Mo2O9 (<5%), Fe doping cannot suppress the phase transition that occurred around 570°C, but 2.5% K doping at La site at the same time (e.g. in sample La1.95K0.05Mo1.95Fe0.05O9-?) can completely suppress this phase transition and increase conductivity at lower temperatures.