From Order to Disorder: NMR Insights into Ionic Conduction in Li-Ion Solid Electrolytes

Abstract

Nuclear magnetic resonance (NMR) spectroscopy provides detailed insights into the working principles of ionic and mixed conductors used in rechargeable battery applications. Notably, NMR is sensitive to crystalline, disordered or even amorphous phases that arise during electrochemical cycling, and can provide atomic-level structural information, as well as insights into the dynamics of ion motion. In this talk, I will present our recent work on Li-ion conducting rocksalt halides [1] and Li-conducting polymeric ionic liquids [2]. Using a combination of synchrotron X-ray diffraction/scattering, electrochemical impedance spectroscopy (EIS), solid-state NMR, pulsed field gradient NMR (PFG-NMR), NMR relaxometry, and first principles calculations, we provide a multiscale understanding of ion diffusion processes and link these findings to local structure features, crystallinity, and materials synthesis/processing conditions.[1] Sebti, E., Evans, H., Chen, H., Richardson, P., White, K., Giovine, R., Koirala, K. P., Xu, Y., Gonzalez-Correa, E., Wang, C., Brown, C., Cheetham, A., Canepa, P., Clément, R.*, "Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor", J. Am. Chem. Soc., accepted. DOI: 10.1021/jacs.1c11335.[2] Jones, S., Nguyen, H., Richardson, P., Chen, Y.-Q., Wyckoff, K., Hawker, C., Clément, R., Fredrickson, G., Segalman, R., "Design of Polymeric Zwitterionic Solid Electrolytes with Superionic Lithium Transport", ACS Cent. Sci., 8(2), 169-175 (2021). DOI: 10.1021/acscentsci.1c01260.