Fig. 7: Physicochemical characterization of the cycled high-loading NCM811 cathodes with different electrolytes.

SEM images of the NCM811 cathode surface after 50 cycles in the BE (a) and AFE (d). SEM images of the NCM811 cathodes cross-sectioned after 50 cycles in the BE (b and c) and AFE (e and f). TEM analyses of the NCM811 particles after 50 cycles in the BE (g) and AFE (h). XRD of the NCM811 cathodes (i–k) before and after 50 cycles in the BE and AFE. Al 2 p (l) XPS spectra of the NCM811 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 NCM811 surface after 50 cycles. All the cells were charged and discharged between 3.0 and 4.5 V at 60 mA g⁻¹ for 50 cycles, and the voltage of the cell was 3.0 V before disassembly.