Thermal stability, oxygen non-stoichiometry, electrical conductivity and diffusion characteristics of PrNi_(0.4)Fe_(0.6)0_(3-δ), a potential cathode material for IT-SOFCs

摘要

The potential use of a double B mixed-perovskite as a promising cathode material in intermediate temperature solid oxide fuel cells (IT-SOFCs) has been anticipated as a result of this work. A thorough investigation of some important parameters like thermal stability, thermal expansion, oxygen non-stoichiometry, electrical conductivity and diffusion characteristics of the PrNi_(0.6)Fe_(0.4)O_(3-δ) ceramic sample have been investigated as functions of temperature (20-1000℃) and oxygen partial pressure (0.6-21,000 Pa). According to the measurements, the composition was phase stable at pO_2 ＞ 1 Pa up to 1000℃ and shows p-type semiconductivity with a low conductivity versus pO_2 dependence. The perovskite has been found to have comparable thermal expansion coefficients with those of commonly used solid electrolytes like CeO_2 and ZrO_2 based oxides, in case of the chemical diffusion experiments higher oxygen diffusion mobility observed during reduction processes in comparison with those during oxidation have been explained by the already known formation of neutral defect clusters.