POTENTIOSTATIC STEP TECHNIQUE TO STUDY IONIC TRANSPORT IN MIXED CONDUCTORS

A potentionstatic step technique was used to measure oxygen transport in the mixed-conducting perovskite SrCo1-xFexO3-delta where x = 0.2, 0 .5 and 0.8. A solid state sealed electrochemical cell configuration wa s employed for this purpose featuring a single crystal yttria-stabiliz ed zirconia solid electrolyte. The chemical diffusion coefficient of o xygen was found to be fast but highly thermally activated. At 850 degr ees C, the chemical diffusion coefficient for oxygen was in the range 10(-7)-10(-6) cm(2)/s With the SrCo0.5Fe0.5O3-delta composition exhibi ting the higher value. Such rapid rate of oxygen transport makes this material attractive for oxygen selective membranes for high temperatur e gas separation applications.