Fig. 5: Characterizations of cathode interface evolution.

a HRTEM images of NCM523 cathode particles before and after 200 cycles. b 2D TOF-SMIS measured LiF images of NCM523 cathode surface before and after 200 cycles. c–e XPS analysis of F 1s (c), C 1s (d), and N 1s (e) spectrum of the NCM523 cathode before and after 200 cycles.