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Mapping the Various Li + Jump Pathways in Li 10 GeP 2 S 12 : From Ultraslow Exchange to High-Temperature Diffusion

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The solid electrolyte Li 10 GeP 2 S 12 is known to exhibit exceptionally fast Li + diffusion within its tetragonal crystal structure. Experimentally, however, the various Li + hopping processes remain incompletely understood. In this study, we employed 7 Li spin-alignment echo (SAE) NMR and complementary NMR techniques to resolve lithium-ion dynamics in LGPS over nearly 12 orders of magnitude in jump rates, from ultraslow local exchange at 90 K to fast long-range diffusion close to room temperature. Our data reveal a sequence of dynamic regimes and activation energies that reflect the dimensional evolution of Li + transport, from localized 1D hopping to full 3D diffusion. The SAE NMR decay rates, which directly reflect slow Li + jump rates, on the order of one jump every three seconds (0.32(2) s –1 ) at 90 K, reveal two distinct dynamic regimes with activation energies of 0.09 and 0.18 eV, suggesting a transition from 1D to 2D diffusion. At higher temperatures, a third regime emerges, characterized by an activation energy of 0.28 eV, detected by NMR relaxation and SAE NMR. This regime likely corresponds to 3D Li + transport, and the measured rates are in excellent agreement with those from pulsed field gradient NMR, quasi-elastic neutron scattering, and theoretical predictions.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c10283