Fermi Potential across Working Solid Oxide Cells with Zirconia or Ceria Electrolytes

Two kinds of electrochemical relevant potentials are important in order to describe several observed phenomena in operating electrochemical cells with solid electrolytes. This paper gives illustrative examples of how the profiles of the two potential types, the Galvani potential, φ, and the electromotive – also called the Fermi potential, π, will vary across the electrolyte, and of how the electron leak current density though the electrolyte, which is related to π, will be affected by temperature and cell voltage across the electrolyte in cells based on gadolinia doped ceria (CGO) and on yttria stabilized zirconia (YSZ) electrolytes.

The nature of the two potential types and the importance of each of them for the cell operation are explained.