OxidIonenleiter

OxidIonenleiter, also known as oxide ion conductors or oxygen ion conductors, are a class of solid materials that exhibit significant ionic conductivity, specifically due to the movement of oxide ions (O2-) through their crystal lattice. These materials are typically ceramics and play a crucial role in various electrochemical applications, most notably in solid oxide fuel cells (SOFCs).

The conductivity in oxide ion conductors arises from defects within their crystal structure. When certain elements with lower valence are substituted into the lattice of a metal oxide (e.g., doping zirconia with yttria), oxygen vacancies are created. These vacancies act as hopping sites for oxide ions, allowing them to move under an applied electric field or concentration gradient. The efficiency of this ionic transport depends on factors such as the material's composition, crystal structure, operating temperature, and the concentration of defects.

Key examples of oxide ion conductors include stabilized zirconia, such as yttria-stabilized zirconia (YSZ), and gadolinia-doped ceria (GDC). These materials possess high ionic conductivity at elevated temperatures, typically above 600 degrees Celsius. Their ability to selectively conduct oxide ions makes them indispensable as electrolytes in SOFCs, where they facilitate the electrochemical reaction between fuel and oxidant. Beyond SOFCs, oxide ion conductors are also explored for oxygen separation membranes, sensors, and catalytic applications.