A coarse-grained simulation method to predict NMR spectra of ions diffusingin porous carbons is proposed. The coarse-grained model uses input frommolecular dynamics simulations such as the free-energy profile for ionicadsorption, and density-functional theory calculations are used to predict theNMR chemical shift of the diffusing ions. The approach is used to compute NMRspectra of ions in slit pores with pore widths ranging from 2 to 10 nm. Asdiffusion inside pores is fast, the NMR spectrum of an ion trapped in a singlemesopore will be a sharp peak with a pore size dependent chemical shift. Toaccount for the experimentally observed NMR line shapes, our simulations mustmodel the relatively slow exchange between different pores. We show that thecomputed NMR line shapes depend on both the pore size distribution and thespatial arrangement of the pores. The technique presented in this work providesa tool to extract information about the spatial distribution of pore sizes fromNMR spectra. Such information is diffcult to obtain from other characterisationtechniques.
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