Assessment of Grain Boundary Compositional Effects in Concentrated Ceramic Oxides*

Ceramic oxides are used for a wide variety of technologically relevant applications from gas sensing systems to catalysis. For device applications such as novel resistive switching devices or oxygen sensors. Applications such as these typically rely upon the ability of oxides to conduct ions efficiently through the lattice. Recent nanoscale compositional characterization of the grain boundary composition has shown different nominal concentrations of solutes could result in orders of magnitude increase in grain boundary ionic conductivity relative to the undoped samples. Our work investigates the impact that concentrated solutes, located at the grain boundary, play in modulating the grain boundary properties. Computational modeling is employed using density functional theory. This study further develops our understanding of high solute grain boundary composition enabling the development of methods such as selective doping to improve macroscopic ionic conductivity for both the grain and grain boundary.