Lattice simulation method to model diffusion and NMR spectra in porous materials

Area of Science:

• Materials Science
• Computational Chemistry
• Physical Chemistry

Background:

• Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for characterizing materials.
• Understanding ion diffusion in porous carbons is crucial for applications like energy storage.
• Predicting NMR spectra from fundamental simulations can provide detailed material insights.

Purpose of the Study:

• To develop a coarse-grained simulation method for predicting NMR spectra of ions in porous carbons.
• To correlate NMR spectral features with pore size distribution and spatial arrangement.
• To offer a novel approach for extracting pore structure information from NMR data.

Main Methods:

• Coarse-grained simulation incorporating molecular dynamics (MD) derived free-energy profiles.
• Density-functional theory (DFT) calculations for predicting NMR chemical shifts.
• Modeling of ion diffusion and exchange dynamics within slit pores (2-10 nm width).

Main Results:

• Computed NMR spectra exhibit pore size-dependent chemical shifts for ions in mesopores.
• Simulations accurately reproduce experimentally observed NMR line shapes by including inter-pore exchange.
• Calculated NMR line shapes are sensitive to both pore size distribution and pore spatial arrangement.

Conclusions:

• The developed simulation technique enables prediction of NMR spectra for ions in porous carbons.
• NMR spectra can be used to infer detailed information about pore size distribution and spatial arrangement.
• This method provides a valuable tool for materials characterization, complementing existing techniques.