Studies on structural, morphological and electrical properties of Ce1−xGdxO2−(x/2)

The gadolinium-doped ceria (GDC) is considered as one of the most promising electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs). Since the operating temperature of SOFC mainly depends on properties of electrolytes, the structural, morphological and electrical properties of GDC are studied as a function of concentration of 'Gd' and sintering temperature. The lattice parameter, density, surface morphology and conductivity of GDC samples are improved upon sintering. Further an increase in lattice parameter with concentration of Gd confirms the dissolution of Gd2O3 in CeO2. The crystallite size and grain size was observed to decrease with “Gd” concentration. All GDC samples sintered at 1773 K showed uniform and smoother surfaces with conductivity ∼0.1 S cm−1 at 1023 K and activation energies less than 0.9 eV. An impedance study confirms the formation of well-grown grains at higher sintering temperature.