This is a webinar event.
Speaker: Nicholas H. Bashian, Department of Chemistry, University of Southern California – Los Angeles
Title: On the Role of Polyhedral Rotations in Mediating Ion Insertion Processes for Energy Storage Materials
Abstract: Understanding the structural transformations that materials undergo during the insertion and deinsertion of ions is crucial for designing next-generation intercalation electrode materials. Using a combination of operando measurement techniques, including X-ray diffraction and X-ray absorption spectroscopy, it is possible to paint a detailed picture of crystallographic changes that occur in battery electrodes during cycling. This allows for a more complete description of the atomic motion and structural rearrangement occurring in intercalation hosts. By combining careful electrochemical measurements with detailed structural characterization and analysis, it is possible to understand the relationship between crystal structure and physical properties in energy storage materials. I will present a study of the structural distortions of the metallic defect perovskite ReO3 upon lithiation, demonstrating that phase transformations during alkali ion intercalation are the result of local strains in the lattice. These phase changes ultimately degrade the reversible capacity of this material. This will be followed by examining the isostructural NbO2F and its shear derivative Nb3O7F to probe the role of edge-sharing octahedral planes in suppressing phase changes. These planes modulate structural stability and ionic transport pathways playing an intimate role in the mechanism of ion insertion and cycling performance of shear compounds.
Bio: Nicholas Bashian recently completed his Ph.D. at the University of Southern California, where he worked with Professor Brent Melot. His research focused on understanding the relationship between structural rearrangement in intercalation electrode materials and their electrochemical properties. To do this, he has employed a mix of structural characterization techniques such as X-ray diffraction, X-ray absorption spectroscopy, and solid state nuclear magnetic resonance measurements. Prior to his Ph.D. work, Nicholas began his scientific career at The Ohio State University where he received his B.S. in chemistry in 2016 and was inspired to pursue academic research. During his time at Ohio State, Nicholas worked with Professor Anne Co studying lithium-tin conversion electrode materials as well as the effects of gamma radiation on Li-ion battery cycling performance. Nicholas has been the recipient of several awards, both from graduate and undergraduate work, including the 2020 Kenneth Nobutoshi Wachi Award for outstanding research and excellence in service for his mentorship of undergraduate researchers.
Seminar Host: Steve Martin
Zoom Link: https://iastate.zoom.us/j/94333291152