Effect of Annealing Temperature and Dopant Concentration on the Conductivity Behavior in (DyO 1.5 ) x –(WO ₃ ) y –(BiO 1.5 ) 1−x−y

Cubic‐stabilized ((DyO 1.5 ) x –(WO 3 ) y –(BiO 1.5 ) 1− x − y ) electrolytes (DWSB) having higher conductivity than (ErO 1.5 ) 0.2 (BiO 1.5 ) 0.8 (20ESB) were developed. However, this DWSB composition also experienced a conductivity degradation like other cubic stabilized bismuth oxides in intermediate temperature (IT) ranges, i.e. 500°–700°C. Several DWSB compositions with the same 2:1 dopant content ratio (Dy:W) were annealed to determine the conductivity behavior in the IT range with time. All DWSB compositions maintained their initial conductivity at 700°C, but underwent conductivity degradation at ≤600°C. The effect of total dopant concentration on the conductivity degradation behavior was investigated at 600° and 500°C. It was also found that 8D4WSB, which is the highest conductivity composition, has promise as an electrolyte for an isothermal operation above 650°C or below 400°C.