and Si-SiOx@C in the initial discharge process, respectively, which both show similar results. In the first scan at OCV, the spectra show the silicon peak and D and G band from the carbon frameworks. The intensity of the silicon band at about 520 cm -1 shows a decreasing tendency with lithiation. As shown in Fig. and Fig. , the normalized intensity of Si band clearly exhibits a decreasing tendency. This indicates the conversion of silicon from crystalline to amorphous Lithium-Si alloys, which matches the XRD results (Fig. , Fig. ). Moreover, the existence of crystalline silicon rather than fully amorphous under current electrochemical conditions is similar to other studies with the band remaining even after discharge to 0 V . New bands show up after 0.8 V, which corresponds to the reduction of the electrolytes. The ring breathing and skeletal deformation peaks of EC are located at 715 and 893 cm -1 . The peaks at 740 and 903 cm -1 belong to PF6 -and ring deformation of FEC, respectively .