Webinar - Prof. Steve Greenbaum: structure and transport in solid electrolytes for lithium batteries
Title of lecture: NMR investigation of structure and transport in solid electrolytes for Li batteries
Authors: Carla Fraenza, Nishani Jayakody, Mounesha Garaga, David Clarkson, Steve Greenbaum; Hunter College of the City University of New York, New York, NY 10065 USA
The major bottleneck in the development of safe and high energy density lithium-based batteries is the lack of a suitable electrolyte needed to eliminate the flammable liquid carbonate electrolyte solvents in use today. Among replacement candidates are a broad array of solid electrolytes based on inorganic oxides and sulfides, ionic liquids (ILs) immobilized in a pseudo-solid matrix, and polymers.
Our laboratory is focused on application of various nuclear magnetic resonance (NMR) techniques to help understand structure and dynamics of energy storage materials, in particular novel electrolytes. In this presentation we discuss two recent collaborative efforts.
(i) In collaboration with UCLA (B. Dunn, D. Ashby), we have investigated ionogels, which are pseudo-solid-state electrolytes consisting of the IL BMIM TFSI plus LiTFSI salt electrolyte confined in a mesoporous silica matrix. We report here NMR measurements of ionic self-diffusion coefficients as well as fast field cycling broadband relaxometry with emphasis on elucidating confinement effects of the silica matrix on ionic transport.
(ii) With Ionic Materials, Inc. (M. Zimmerman, R. Leising), we discuss results for a solid polymeric electrolyte based on semicrystalline polyphenylene sulfide and Li salts such as LiTFSI and LiFSI. This polymer electrolyte can be reliably extruded into thin films, is non-flammable, has attractive mechanical properties for lithium dendrite suppression, is electrochemically stable against Li, and is compatible with a variety of different cathodes, including NMC811. NMR diffuser measurements reveal Li room temperature self-diffusion coefficients that are the highest in any known solid.