The composition, morphology and thickness of solid electrolyte interphase (SEI) on silicon anodes are dictated by multiple factors such as surface chemistry, electrolyte composition, chemical passivation effects etc. Further the SEI constantly evolves, as it is electrochemically lithiated (delithiated) during the enormous volume changes. SEI on silicon typically is reported to be in the range of tens of nanometers and can be compositionally heterogeneous. Normal vibrational spectroscopy techniques such as micro-Raman and FT-IR while pretty useful, provide chemical information at a relatively bulk scale, typically much > 100 nm from the sample surface.This makes it harder for getting information from the real SEI, which can be only order of tens of nanometer. Tip Enhanced Raman Spectroscopy (TERS) is based on the field enhancement of Raman active signal locally at regions close to the tip. The Raman cross section is enhanced at least several orders of magnitude due to resonance coupling between surface plasmon modes (of the tip) and the electromagnetic field of the excitation laser. TERS enables simultaneous chemical mapping and topography at a nanoscale spatial resolution. TERS mapping of cycled amorphous silicon show the SEI composition and morphology changing as a function of electrochemical cycles. These observations will be compared with results from other techniques such as X-ray photoelectron spectroscopy