In situ surface enhanced Raman spectroscopic studies of solid electrolyte interphase formation in lithium ion battery electrodes

The use of surfaced-enhanced Raman spectroscopy (SERS) in lithium-ion battery (LIB) and Li-O-2 battery studies has proven to be a powerful tool for observing solid electrolyte interphase (SEI) growth, on the electrode's surface, that is crucial in determining the battery's electrochemical performance. Here, we report the use of SiO2-coated Au nanoparticles for in situ SERS studies during electrochemical cycling to directly observe SEI formation on the electrode. The comparison of silicon electrodes with and without the electrolyte additive vinylene carbonate (VC) shows the formation of VC-related reduction products on the electrode's surface before the reduction of ethylene carbonate. Further observation, using normal Raman and SERS, of the silicon band intensity shows different amorphization rates between bulk and surface. These successful proof-of-concept experiments should allow this technique to be extended to other electrode material studies in conjunction with other surface sensitive techniques to further our understanding of surface reactions that heavily influence overall battery performance. (C) 2014 Elsevier B.V. All rights reserved.