Slice-Selective NMR Diffusion Measurements: A Robust and Reliable Tool for In Situ Characterization of Ion-Transport Properties in Lithium-Ion Battery Electrolytes

The main impediments to the widespread acceptance of electric drive vehicles are the cost, energy-storage capacity, and durability of portable electrical energy sources and, in particular, batteries. In situ experimental techniques that can accurately detect and monitor performance degradation mechanisms on the nanoscale, including the identities of short-lived chemical species and changes in materials properties as a function of cycling rate, temperature, or time, are not widely used. Herein we demonstrate the combination of in situ ID imaging and slice-selective NMR diffusion measurements as a tool for the spatially and temporally resolved determination of lithium diffusivities in a conventional liquid electrolyte (1.0 M lithium bis(trifluoromethanesulfonyl)imide solution in propylene carbonate) under application of a constant electrical current. All experiments were carried out using standard NMR equipment, so the proposed technique can be easily implemented in any modern R&D facility.