Proton Conductivity Studies of Y-Doped Barium Zirconate: Theoretical and Experimental Approaches

Abstract

The proton conductivities of BaZr1-xYxO3-δ (BYZ) pellet samples with x = 0.06 to 0.4 were studied. The analysis showed that the optimum doping concentrations for bulk and grain boundary proton conductivity were at x = 0.1 and 0.2, respectively. The activation energies of the proton conductivity in bulk were between 0.42-0.47 eV, and 0.68-0.82 eV in the grain boundary. To gain more insight into the ionic conductivity mechanism in BYZ, quantum simulations complemented with kinetic Monte Carlo technique was employed to simulate proton and oxide ion migration processes in 8-30 at.% BYZ supercell. The results reveal the effect of defect associations on the proton and oxide ion migration and confirm the domination of proton conductivity on the overall ionic conductivity at all doping concentrations throughout the temperature range of this study. The optimum doping concentrations for the proton and oxide ion conductivities were extracted and compared with the experimental results.