ABSTRACT
Solid electrolytes based on stabilized zirconia have been studied since the discovery of electrolytic oxygen evolution from ZrO
-Y
O
solid solutions (Nernst glower) by Nernst in 1899. Perhaps this was the first finding which clearly illustrated that ionic conductivity exists in the solid state. The ionic conductivity in those solid solutions occurs via oxide ionic vacancies (V
) generated due to charge compensation. Stabilized zirconia ceramics have been the subject of extensive scientific research during the last 30-35 years owing to the diverse technological applications. These materials have been used in fuel cells, oxygen separators, oxygen pumps, and electrochemical gas sensors, throughout which there have been two primary areas of research: (1) optimization of the manufacturing technology and structure of the stabilized zirconia, and (2) development of knowledge relating to the solid electrolyte-electrode interface. While it is well recognized that both directions reached the level of their maturity, there still seems to be some dispute regarding the explanation of complexity of physical and electrochemical processes on the electrolyte-electrode interface.
