The Solid Oxide Fuel Cell is a particular case in which an oxide is used as a conductor. Once i've heard that oxides usually aren't good conductors but it turned out that a lot of oxides are conductors. What i am asking is :
How can i know if a oxide is a conductor or not?
If there isn't any conduction band since it's not a metal, how do the electrons move and how does the SOFC work?