Fast ion conduction is one of the key requirements to achieve technological advances in oxide-based energy applications, including solid oxide fuel cells, batteries, and catalysts. Recently, with the development of nanoscale thin film technologies, oxide heterostructures have attracted growing attention for enhancing ionic conductivity due to the effect of interfacial lattice strain. However, conventional straining along the lateral direction of the substrate surface is impractical as many practical devices require ions to move across the interfaces between electrodes and electrolytes. This project aims to develop a new design concept for oxide heterostructures with an exceptionally large number of interfaces that are designed to direct energy flow by controlling the orientation of interfaces for fast ion transport along the interfaces. We will synthesize vertical heteroepitaxial nanostructures with fluorite Gd-doped CeO2 (GDC) and bixbyite RE2O3 (RE = Y and Sm) by pulsed laser deposition and understand fast ion transport properties by modulating interfacial strain. This project will establish an atomic-scale foundation for controlling and tuning interfacial ion transport by strain. In addition, the proposed vertical heteroepitaxial nanostructures will significantly improve oxygen ion conduction by providing a high-density ion flux along the interfaces.
Dr. Dongkyu Lee is an assistant professor of Mechanical Engineering at the University of South Carolina. His current research interests lie at the intersection of synthesizing functional oxide materials by atomic control, understanding energy conversion and storage mechanisms as well as the physicochemical properties of materials, and applying a fundamental understanding to design advanced energy devices. He received his Ph.D. in Mechanical Engineering from MIT in 2014, and then moved to a postdoctoral position in the Materials Science and Technology Division at the Oak Ridge National Laboratory.August 2020