fig4

Figure 4. SEM images of (A) pristine graphite anode and cycled graphite anodes in (B) LiDFOB + DMS/HFE/FEC and (C) LiPF₆ + EC/DMC electrolytes. Depth-profiling XPS spectra of the graphite anode at different sputtering times: (D) C 1s, (F) Li 1s and (H) O 1s regions. Normalized relative contents of representative chemical bonds of graphite anodes as a function of sputtering time: (E) C 1s, (G) Li 1s and (I) O 1s. The 3D TOF-SIMS rendering images and corresponding sputtering-time profiles using different electrolytes: (J) LiF₂^-, (K) LiBFO₂^- and (L) PO₂^-. Long-term cycling performance of LiCoO₂||graphite cells with different electrolytes (M) at 25 °C and (N) at -20 °C.