Figure 4. In situ SEM images of a Si thin flake anode during charge/discharge processes.

(a) The charge/discharge curves of a Si thin flake anode recorded in constant current and constant voltage (CC/CV) mode with cut-off voltages ranging between −3.88 V and −2.40 V (vs. LiCoO₂). The CC rates for the charge and discharge were 0.5 C. (b) In situ SEM images taken before and after the 3rd cycle. (c) Schematic drawings of two expansion models during the lithiation process revealed by in situ SEM. (d,e) In situ SEM images of a Si thin flake taken from the side after (d) the charge and (e) discharge processes.