Phase stability o f the mixed-conduction Sr-Fe-Co-O system

摘要

Mixed-conducting ceramic oxides have potential uses in high-temperature electrochemical applications such as solid oxide fuel cells, batteries, sensors, and oxygen-permeable membranes. The Sr-Fe-Co-O system conbines high electronic/ionc conductivity with appreciable oxygen permeability at elevated temperatures. Dense ceramic membranes made of this material can be used to separate high-purity oxygen from air without the need for external electrical circuitry, or to partially oxidize methoane to produce syngas. Samples of Sr_2Fe_(3-x)Co_xO_y (with x chemical 0, 0.6, 1.0, and 1.4) were prepared by solid-state reaction method in atmospheres with various oxygen partial pressures (pO_2) and were characterized by X-ray diffraction, scanning electron microscopy, and electrical conductivity testing. Phase components of the sample are dependent on cobalt concentration and pO_2. Electrical conductity increases with increasing temperature and cobalt content in the material.