What is Gadolinium-doped ceria?

Gadolinium-doped ceria oxide, gadolinium-doped, and GCO, formula Gd:CeO2] is a ceramic electrolyte used in solid oxide fuel cells. It has a cubic structure and a density of around 7.2 g/cm in its oxidised form. It is one of a class of ceria-doped electrolytes with higher ionic conductivity and lower operating temperatures than those of yttria-stabilized zirconia, the material most commonly used in SOFCs. Because YSZ requires operating temperatures of 800–1000 °C to achieve maximal ionic conductivity, the associated energy and costs make GDC a more optimal material for commercially viable SOFCs.