Solvation layers, also called electric double layers (EDLs), crucially modulate all the electrochemical processes at electrode-electrolyte interfaces, and serve as "precursors" for the nucleation and growth of interphasial species. However, the molecular structure of EDLs remains largely elusive. In this talk, I will discuss our recent efforts on characterizing the EDL structure via scanning probe microscopy and vibrational spectroscopy. Furthermore, I will show our efforts on imaging the nucleation and growth processes of solid-electrolyte interphases (SEIs) on graphite electrodes. In the end, I will discuss about the correlation between EDL and SEI, and the implications on the design of battery electrolytes.