Understanding the Physical Properties of Pr-Gd Co-Doped Ceria and Its Role As the Interlayer in Solid Oxide Cells

Abstract

In solid oxide cells, a doped ceria interlayer is widely applied between the state-of-the-art yttrium-stabilized zirconia electrolyte and the oxygen electrode to mitigate thermal expansion mismatch and chemical interactions for extended durability. The conventional gadolinium doped ceria is usually a pure ionic conductor and blocks electronic currents under oxidative atmosphere. Adding electronic conduction to the interlayer may increase triple phase boundary areas, thus decrease charge transfer resistance and improve electrode stability. The addition of Pr in Gd-doped ceria results in unique physical properties such as an oxygen partial pressure (pO2) dependent ionic conductivity and electronic conduction in a wide range of pO2. In this study, Pr/Gd co-doped ceria (PGCO) is prepared with varying doping levels and its physical properties such as ionic and electronic conductivities are measured under different oxygen partial pressures and temperatures. PGCO with varying Pr/Gd doping is investigated as interlayer for solid oxide cell applications.