About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
|
Advanced Materials for Energy Conversion and Storage VII
|
Presentation Title |
Direct Correlation of Anion Conductivity with Grain Boundary Defect Chemistry in Concentrated Oxide Solid Solutions |
Author(s) |
Hasti Vahidi, Shengquan Xuan, William Bowman |
On-Site Speaker (Planned) |
William Bowman |
Abstract Scope |
Ionic conductivity of polycrystalline oxides is impacted by grain boundaries (GBs), which can exhibit substantially lower conductivity than grains. This is due to space charge layers (SCLs) at the GBs, where mobile charge carrier, i.e. oxygen vacancies, depletion has been observed. Modeling of the SCLs has been mainly focused on dilute solutions, using dilute-solution thermodynamic approximations, with only few studies on concentrated solid solutions where point defect concentrations exceed ~ 1 at%. This work aims to bridge the gap between GB ionic conductivity and defect chemistry in heavily Gd-substituted CeO2 (GdxCe1-xO2) using direct measurements of chemical and functional properties over a range of compositions. Electrochemical impedance spectroscopy (EIS) is used to measure grain and GB conductivity, and TEM-based electron energy-loss spectroscopy (EELS) is used to quantify the local defect chemistry. Together, these data contribute to development of models of GBs and interface transport ion mechanisms in concentrated solid solutions. |
Proceedings Inclusion? |
Planned: |