IR Near-Field Study of the Solid Electrolyte Interphase on a Tin Electrode.

There has been a dearth of suitable techniques for studying the chemical composition of solid electrolyte interphase (SEI) on Li-ion negative electrodes at a resolution of its basic building blocks' length scale. Infrared apertureless near-field scanning optical microscopy (IR aNSOM) is an emerging tool in the chemical characterization of interfacial layers on the nanometer scale. This work demonstrates an IR aNSOM imaging of the SEI layer on a model Sn electrode. IR aNSOM images reveal significant chemical contrast variations tied to specific topographic features and possible corresponding distribution of lithium carbonate and lithium ethylene dicarbonate on the Sn electrode surface.