Advancing the Probing of Li Dynamics in NMR: Isotope Dilution Effects on Spin-Alignment Echo Generation
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Solid-state diffusion plays a critical role in materials science, particularly in the precise measurement of ion dynamics in materials with structural disorder. Spin-alignment echo (SAE) nuclear magnetic resonance (NMR), which is comparable to exchange spectroscopy, has proven to be a powerful technique for probing (ultra)slow Li dynamics, even in amorphous materials. However, 7 Li NMR Jeener-Broekaert echoes can be influenced by the simultaneous generation of dipolar and quadrupolar order. In many cases, the dipolar interactions can be suppressed by selecting evolution times ( t p ) shorter than 20 μs. In this study, glassy Li 2 Si 3 O 7 is used as a model system to investigate the positive impact of isotope dilution on 7 Li SAE NMR. Specifically, we explore how the reduction of homonuclear dipole–dipole interactions through spatial separation of spin-3/2 probe nuclei influences the results. Two samples were analyzed: one with 100% 7 Li and the other with 5% 7 Li (95% 6 Li). The samples were studied using mixing-time and preparation-time dependent 7 Li SAE NMR. Jeener-Broekaert echoes and their Fourier transforms reveal that, for sufficiently short t p, dipolar interactions can be entirely suppressed in the diluted sample with reduced 7 Li– 7 Li dipolar interactions. Fortunately, at sufficiently high temperatures, the activation energies and decay rates of the diluted sample closely match those of the 100% 7 Li sample, demonstrating the robustness of SAE NMR in accurately determining dynamic parameters that characterize slow Li + ion dynamics in condensed matter.
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funder: Deutsche Forschungsgemeinschaft
Award: G28549651
OpenAlex ID: W4414205993