Related Experiment Video
Updated: May 12, 2026

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging
Published on: September 2, 2016
Two-dimensional diffusion in Li0.7NbS2 as directly probed by frequency-dependent 7Li NMR.
1Graz University of Technology, Institute for Chemistry and Technology of Materials, Graz, Austria. viktor.epp@tugraz.at
Nuclear magnetic resonance (NMR) spectroscopy revealed Li ion diffusion in Li0.7NbS2. The study characterized Li self-diffusion dynamics and dimensionality within the van der Waals gap, showing a 2D diffusion process.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Physical Chemistry
Background:
- Layered transition metal dichalcogenides like Li0.7NbS2 are promising for energy storage applications.
- Understanding ion diffusion mechanisms is crucial for optimizing material performance.
- Nuclear magnetic resonance (NMR) spectroscopy offers atomic-scale insights into dynamic processes.
Purpose of the Study:
- To investigate Li ion diffusion in Li0.7NbS2 using NMR spectroscopy.
- To characterize the self-diffusion process, including jump rates and activation energy.
- To determine the dimensionality of Li ion diffusion and the effect of annealing on dynamics.
Main Methods:
- Utilized (7)Li NMR spin-lattice relaxation (SLR) rates (R1ρ) in the rotating frame.
- Performed temperature-variable SLRρ measurements to determine dynamic parameters.
- Conducted frequency-dependent measurements to assess diffusion dimensionality.
Main Results:
- SLRρ rates showed a diffusion-induced relaxation peak at 320 K for an annealed sample.
- Deduced a Li jump rate of approximately 1.3 × 10^5 s⁻¹ at 300 K and an activation energy of 0.43(2) eV.
- Observed a logarithmic frequency dependence of relaxation rates, indicating low-dimensional (2D) diffusion.
Conclusions:
- NMR spectroscopy effectively probes Li self-diffusion in layered materials.
- Li ion diffusion in Li0.7NbS2 occurs predominantly in two dimensions within the van der Waals gap.
- Annealing influences Li ion distribution and dynamics, impacting overall diffusion behavior.
More Related Videos
11:25In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries
Published on: November 10, 2014
08:42High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions
Published on: October 10, 2014
Related Concept Videos
Two-Dimensional (2D) NMR: Overview
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
2D NMR: Overview of Homonuclear Correlation Techniques
COSY90 is the standard two-dimensional (2D) COSY experiment that...
NMR Spectroscopy: Chemical Shift Overview
For instance, the proton...
Other Nuclides: 31P, 19F, 15N NMR
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
Chemical Shift: Internal References and Solvent Effects
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...