|About this Abstract
||MS&T23: Materials Science & Technology
||Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
||Which Interfaces Matter Most? Variability in Grain Boundary Defect Chemistry and Conductivity in a Concentrated Solid Electrolyte
||Hasti Vahidi, Alejandro Mejia, Shengquan Xuan, Angel Cassiadoro, Abednego Abdi, David Mebane, William Bowman
|On-Site Speaker (Planned)
The diminished grain boundary (GB) conductivity in polycrystalline oxides remains a significant drawback to highly conductive solid electrolytes for applications including solid oxide fuel/electrolysis cells and solid-state batteries. While current models explain the near-GB defect behavior in dilute solid solutions, incorporate defect-defect interactions (in concentrated solutions), and chemo-mechanical stress, there is yet to be a new model that predicts individual GB conductivities in concentrated solid-solutions via direct experimental measurements of near-GB defect chemistry. Here,  we present a novel experimental-computational approach that predicts which GBs in a polycrystalline solid electrolyte will likely facilitate ionic conductivity. By microscopically measuring the GB-to-GB variability in point defect concentrations and applying a new thermodynamic phase field modeling framework, we revealed a non-monotonic relationship between oxygen vacancy depletion and GB ionic conductivity. This lays the foundation for the design of functional solid electrolytes essential in energy applications.
 H. Vahidi … W.J. Bowman (Submitted)