Fig shows the FE SEM

Fig. 1 shows the FE-SEM and FE-TEM images of pristine Si and Si@C. The representative FE-SEM image of pristine Si revealed a flat and smooth surface, whereas those of Si@C revealed Si particles that 6XHis were fully covered with carbon carbonized at 1000 °C. The FE-TEM image of Si@C shows that the thickness of the carbon layer was ∼100 nm. Furthermore, the carbon layer was confirmed to be amorphous by the XRD of the Si@C and pristine Si particles (Fig. 2). Compared to pristine Si particles, the Si@C particles exhibited a broad peak of amorphous carbon at 2θ in the range 20°–30°, with all the other distinct diffraction peaks being observed at 28.4°, 47.2°, 56.0°, and 68.9°, corresponding to the (1 1 1), (2 2 0), (3 1 1), and (4 0 0) planes of the '6XHis' pristine Si phase (JCPDS 01-0787), respectively. No peaks corresponding to the bulk SiO2 and SiC crystalline phases were observed in the diffraction pattern of Si@C, indicating cristae the SiO2 and SiC crystalline phases did not form during carbonization.