CANCELLED - IMSE Seminar with Shrayesh N. Patel on Interplay between Ion Solvation and Dynamics
Due to unexpected circumstances, the IMSE Seminar and faculty meetings with Dr. Shrayesh Patel have been cancelled.
Polymer electrolytes are important class of solid electrolytes for enabling high-energy density lithium batteries. Fundamentally, ion-polymer coordination, inter-connectivity of solvation sites, and corresponding ion-solvating polymer dynamics are critical in understanding the limits of ionic conductivity. Here, the importance of these effects is highlighted in a series of combined experimental and computational studies on model lithium-ion conducting polymer electrolytes.
First, we focus on graft polymer architectures of poly[(oligo ethylene oxide) methyl ether methacrylate] (POEM) varying oligo side-chain lengths. With addition of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the observed differences in ionic conductivity between the POEM derivatives and linear poly(ethylene oxide) (PEO) cannot be adequately explained by differences in Tg. Importantly, the limits of ionic conductivity are dictated by the segmental mobility of the ethylene oxide units that form effective solvation sites, rather than system-wide dynamics.
Second, we extend our study to copolymers consisting of highly flexible POEM and a high polarity functional group containing poly(glycerol carbonate methacrylate) (PGCMA). Interestingly, conductivity is reduced by the addition of the glassy PGCMA, but no enhancement from its high polarity. This is because the PGCMA groups, despite their high polarity, do not solvate lithium ions. Lastly, the talk will end with results from ongoing work focusing on solvation site formation and ion transport mechanisms in conjugated polymer electrolytes.
Shrayesh Patel completed his undergraduate degree at the Georgia Institute of Technology in Chemical and Biomolecular Engineering in 2007, then received his PhD in chemical engineering from the University of California, Berkeley in 2013. Patel Group focuses on functional polymers (e.g. electronic conductors, ion conductors, redox-active) for energy conversion and storage applications. The current focus is on batteries and thermoelectrics. The group has a strong expertise in the characterization of polymers that allows us to understand charge transport, electrochemical and morphological properties. We frequently leverage synchrotron x-ray scattering and spectroscopy techniques to advance our understanding of functional polymers at the molecular, nano-, and micro-scale.