Graphite thin film anodes with a high IR reflectivity have been prepared by a spin coating method. Both ex situ and in situ mi- croscope FTIR spectroscopy (MFFIRS) in a reflection configuration were employed to investigate interfacial processes of the graphite thin film anodes in lithium-ion batteries. A solid electrolyte interphase layer (SEI layer) was formed on the cycled graphite thin film anode. Ex situ MFTIRS revealed that the main components of the SEI layer on cycled graphite film anodes in 1 tool L 1 LiPF6/ethylene carbonate + dimethyl carbonate (1:1) are alkyl lithium carbonates (ROCOzLi). The desolvation process on graphite anodes during the initial intercalation of lithium ion with graphite was also observed and analyzed by in situ MFTIRS.