Solid-state NMR studies of chemical exchange in ion conductors for alternative energy applications

Here we describe the selective inversion methodology for quantifying the rates of site-specific ion exchange in materials such as lithium ion battery cathode frameworks. This strategy is shown to be robust in the presence of paramagnetic centers and viable and efficient for the evaluation of hopping rates, in spite of varying initial conditions for the NMR experiment. This is contrasted with 2D EXSY methodology, and selective inversion is shown to be preferable for a number of reasons articulated herein. Work in this area in our group was guided by insights into chemical exchange processes provide by our friend and colleague, Prof. Alex D. Bain. We dedicate this short review to him.