Fig. 6: Physicochemical characterization of the cycled high-loading NCM622 cathodes with different electrolytes.

SEM images of the NCM622 cathode surface after 100 cycles in the BE (a) and AFE (d). SEM images of the NCM622 cathodes cross-sectioned after 100 cycles in the BE (b and c) and AFE (e and f). TEM analyses of the NCM622 particles after 100 cycles in the BE (g) and AFE (h). XRD of the NCM622 cathodes (i–k) before and after 100 cycles in the BE and AFE. XPS spectra of the Al 2 p (l) spectrum of the NCM622 cathodes in the AFE. TOF-SIMS 3D reconstruction of the sputtered volume (m) and the depth profiling of several secondary ion fragments (n) of Al⁺, AlO₂C₂HF⁻, LiF₂⁻, AlO₂⁻, AlO₂C₂H₂⁻ and C₂HO⁻ on the NCM622 surface after 100 cycles. All the cells were charged and discharged between 3.0 and 4.3 V at 95 mA g⁻¹ for 100 cycles, and the voltage of the cell was 3.0 V before disassembly.