Effect of zinc oxide as a sintering aid on proton migration across Σ5 (310)/[001] tilt grain boundary of barium zirconate

Abstract

The effect of zinc oxide as a sintering aid on proton migration across a barium zirconate super cell with a Σ5 (310)/[001] tilt grain boundary was investigated using density functional theory. The proton was trapped by high energy barriers in the range of 1.28–1.49 eV near the zinc ion that was substituted for a zirconium ion at the grain boundary. However, there were available pathways for proton migration across the grain boundary away from the zinc ion with relatively low energy barriers in the range of 0.61–0.78 eV. Therefore, the zinc ion located at the grain boundary did not affect the energy barrier for proton migration, although the number of mobile protons could decrease as a result of being trapped near the zinc ion.