Hosts: Jessica Schiffman (email@example.com) and Sarah Perry (firstname.lastname@example.org)
Metal-ion rechargeable batteries are the technology of choice for numerous applications, yet the energy density and safety of commercial devices is often limited by using organic liquid electrolytes with high flammability and poor stability of electrode/electrolyte interfaces during operation. Ionic liquids are a class of functional liquid salts that address both voltage and thermal stability concerns. Incorporation of ionic liquid moieties onto a polymer to form polymeric ionic liquids (PILs) synergistically combines the functionality of ionic liquids with the mechanical robustness and mesostructured control imparted by the polymer backbone. I will discuss the design of ionic liquid-metal cation interactions and overall polymer design to create all solid-state polymer electrolytes with high ionic conductivity of Li+ as well as higher valency metal cations relevant to next generation batteries. These metal ion-IL interactions are frequently metal-coordination bonds that simultaneously act as reversible cross-links, lending additional mechanical strength. The metal-ligand bond lifetime therefore determines both the ionic conduction and the time-dependent mechanical properties. Further, this lifetime is shown to dominate performance to a much greater extent than other variables including polymer dielectric constant.
Rachel A. Segalman received her B.S. from the University of Texas at Austin and Ph.D from the University of California, Santa Barbara. She was a postdoctoral fellow at the Université Louis Pasteur before joining the faculty of UC Berkeley and Lawrence Berkeley National Laboratories from 2004-2014 during a portion of this time she also served as the Materials Science Division Director at Lawrence Berkeley National Laboratories. In 2014, she moved to UC Santa Barbara to be the Kramer Professor of Chemical Engineering and Materials and became Department Chair of Chemical Engineering in 2015. In 2018 she also became the Schlinger Distinguished Chair of Chemical Engineering and the Associate Director of the UT/UCSB/LBL EFRC: Center for Materials for Water and Energy Systems. Segalman’s group works on controlling the structure and thermodynamics of functional polymers including polymeric ionic liquids and semiconducting and bioinspired polymers. Among other awards, Segalman received the Journal of Polymer Science Innovation Award, the Dillon Medal from the American Physical Society, the Presidential Early Career Award in Science and Engineering, is an Alfred P. Sloan Fellow and a Camille Dreyfus Teacher Scholar. She is also a Fellow of the American Physical Society, an elected member of the American Academy of Arts and Sciences and the National Academy of Engineering.