Slice-Selective NMR Diffusion Measurements - a Tool for the Characterization of Ion Transport Properties in Lithium Ion Battery Electrolytes

The main impediments to the wide-spread acceptance of electric drive vehicles are the cost, energy storage capacity, and durability of Li-ion batteries. The first issue is best addressed within the context of materials and batteries manufacturing, the second by research on the synthesis and characterization of new materials. Successfully tacking of the third issue requires an improved understanding of battery degradation mechanisms and the development of suitable mitigation measures. In situ experimental techniques which can accurately detect and monitor performance degradation mechanisms at the nanoscale, including the identities of short-lived chemical species, or changes in materials properties as functions of temperature, position or time are emerging only gradually, due to their associated difficulties and complex challenges. We show that the combination of in situ one-dimensional imaging and slice-selective NMR diffusion measurements (Fig. 1) is a tool for spatially and temporally resolving the lithium self-diffusion coefficient in a liquid electrolyte during the application of a dc current (Fig. 2). A solution of 1M LiTFSI in propylene carbonate was used for our method development work.