Examples of the application of electron blocking microelectrodes to the study of ion transport and electrode processes in mixed electronic and ionic conductors were given for a mixed conducting oxide perovskite. Emphasis was placed on the analysis of steady-state current–voltage and cyclic voltammetric curves. Yttria-stabilized zirconia was used as the O-ion conducting micro-contact material. The measurements were performed between 500 and 750C on both encapsulated and non-encapsulated oxide surfaces in order to detect the relative importance of surface O exchange as compared to bulk O ion transport and changes of stoichiometry. The Gd0.8Sr0.2CoO3-δ proved to be a typical mixed conductor with medium O ion conductivity. There was an increasing ion conductivity for decreasing O activities indicating a typical vacancy transport mechanism of O ions. At 700C in air, a value of 2 x 10-4S/cm was obtained for the O ion conductivity of Gd0.8Sr0.2CoO3-δ; with a very weak dependence upon the O partial pressure.

Studies of Ionic Transport and Oxygen Exchange on Oxide Materials for Electrochemical Gas Sensors. H.D.Wiemhöfer, H.G.Bremes, U.Nigge, W.Zipprich: Solid State Ionics, 2002, 150[1-2], 63-77