Explanation

ceramics with high electric conductivity are produced by ions moving in the direction of electric field. According to the type of conductive ions, it can be divided into two categories: cationic conductive ceramics and anionic conductive ceramics. ZrO2 based ceramics doped with low alkaline earth metals such as Ca2+, Mg2+, Y3+, and rare earth metal metal ions are typical anionic conductive ceramics. It is a fluorite (CaF2) type oxygen ion conductor with a large number of oxygen ion vacancy in the structure. Under the action of electric field, oxygen ions can conduct electricity through the diffusion of oxygen vacancy. It can be used as separator of high temperature fuel cell, electrode materials for MHD power generation channel, high temperature heating element under oxidation atmosphere, oxygen sensitive materials, etc. The oxygen ion conductors with fluorite structure also include terbium oxide based, cerium oxide based, hafnium oxide based and bismuth oxide based solid solution. Similar to ion conductive ceramics with fluorite structure, when cations in perovskite type oxides are partially replaced by low valence cations, oxygen ion vacancy will also be generated to maintain electrical neutrality, thus realizing oxygen ion conduction. There are mainly three systems based on LaAI03, CaTia, and SrTiO3. However, the unit cell of crystal center of fluorite structure has a large gap, which is conducive to the migration of oxygen ions, so its ion conduction performance is better than that of perovskite structure. In addition, there are fluoride ion conductor with fluorite and fluocerite structures.

Classification