Protonic and Oxygen-Ion Conduction in Solid Oxide Electrolytes: Final Report, January 1, 1985-March 31, 1988.

摘要

This project has focused primarily on protons in perovskite-related oxides. Particular attention has been given to KTaO sub 3 containing acceptor (transition-metal ion) dopants, which is available as high quality single crystals, and for which the H sup + concentration can be monitored through IR absorption. Techniques used for this study were: electrical conductivity, low-temperature dielectric relaxation, isotope effect on the conductivity (by substituting deuterons for protons), IR absorption and EPR Measurements on the dopants ions. We have observed several dielectric loss peaks, due to Ni, Co, and Mn dopants. No evidence for conduction by the oxygen-ion vacancy was found, but in the reduced state it is possible to obtain electronic small-polaron hopping processes. Other work included the study of ceramic samples of Yb-doped SrCeO sub 3 , for which a low activation energy for protonic migration of 0.65 eV was found. Finally, an approach to analyzing the pre-exponentials of conductivity was developed and applied in an extensive survey of different fast-ion conductors. (ERA citation 13:054262)