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High Resolution Image Download MS PowerPoint Slide Interfaces and interphases play a crucial role in lithium-ion batteries, often determining cell-level performance such as rate capability, safety, and lifetime. Probing chemical and physical processes that occur in these regions is difficult, resulting in a limited understanding of the myriad relevant physicochemical processes and, notably, the properties of the solid-electrolyte interphase (SEI). Operando shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) offers the chemical sensitivity and spatial resolution required to investigate these regions. In this study, we develop a method to quantitatively monitor the lithium-ion concentration at battery interfaces in 2032-format coin cells, using composite electrodes and commercially available materials. With this method we observe transport limitations in the graphite electrode in graphite/lithium iron phosphate full cells─in real time─with a model organic carbonate-based electrolyte solution. The potential applications and versatility of this approach is demonstrated by studying lithium-ion solvation shells and directly observing solid-electrolyte interphase (SEI) changes using the same method. It is hoped that this method will find further adoption in the battery research community for the development and validation of new modelling efforts, the optimization of cell formation and cycling protocols, and the development of new cell chemistries for new battery applications.
Holthuijsen et al. (Tue,) studied this question.