Ceria-based electrolytes have been widely researched in intermediate-temperature solid oxide fuel cell (SOFC), which might be operated at 500 similar to 600 degrees C. Gd0.1Ce0.9O1.95(GDC10) powders were prepared by a modified chemical co-precipitation process with Gd(NO3)3 and Ce(NO3)3 as precursors, and ammonia and hydrogen peroxide as precipitants. The precursors of GDC10 were fired at 350 degrees C for 2 h, then the fluorite structure cerias were identified by X-ray diffraction. The powders are well crystallized, with the size about 5 nm and surface area of 148.3 m2/g. Loading lmol% cobalt oxide as additive, the GDC10 were succeeded to densify at 950 degrees C by liquid phase sintering mechanism. The grain size of 1C0GDC10 is small, about 100 nm. The electrical conductivity of samples sintered at 950 degrees C is about 0.01S/cm at 600 degrees C. The existence of cobalt oxide and smaller grain size of 1CoGDC10 don't affect the electrical conductivity. (C) 2010 Elsevier B.V. All rights reserved.