Structure and conductivity of yttria-stabilized zirconia co-doped with Gd2O3: A combined experimental and molecular dynamics study

Yttria-stabilized zirconia (YSZ) samples co-doped with Gd2O3 in the range 0–4 mol% were prepared and their ionic conductivities were investigated as a function of Gd2O3 concentration by impedance spectroscopy. Bulk conductivity of 8 mol% YSZ electrolyte at temperatures <726 K was enhanced by Gd2O3 co-doping up to levels of 2 mol%, while the total conductivity maxima was achieved at a composition of 2 mol% at temperatures not over than 623 K. Based on analyses of results from both molecular dynamics calculation and experimental investigation, the achievement of higher ordered cubic symmetry is suggested as an explanation for the enhanced conductivity at a relatively low temperature arising from co-doping YSZ with Gd2O3.