Effect of 20 mol % gadolinium doping on oxide ion conductivity of ceria as electrolyte for intermediate temperature solid oxide fuel cells

The gadolinium-doped ceria is investigated as electrolyte materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) due to its oxide ion conductivity. The doping of Gd3+ to Ce4+ can introduce a small strain in the lattice thereby improved conductivity with low activation energy is expected. The 20 mol. % gadolinium doped ceria (Ce0.8Gd0.2O2-delta) nanocrystalline powder is prepared here by citrate -complexation method. The XRD, Rietveld refinement, FTIR, UV-Visible, FESEM/EDX, and a c -impedance techniques are used to characterize this sample. The oxide ion conductivity is determined between 523 -1023 K. The Ce0.8Gd0.2O2-delta shows highest oxide ion conductivity of 6.79 x 10-3 S cm-1 and 1.11 x 10-2 S cm -1 at 973 K and 1023 K, respectively. The Ce0.8Gd0.2O2-delta showed lower activation energies of 1.09, 0.70, and 0.88 eV for grain, grain boundary, and total conduction, respectively. Thus, the nano crystalline Ce0.8Gd0.2O2-delta is proposed as potential electrolyte for ITSOFCs.