fig8

Figure 8. (A) Intensity contour maps (bird’s eye view) showing the evolution of the main characteristic diffraction peaks; Schematic illustration of the crystal structural evolution during the cycling (Reproduced with permission from Ref.^[99]. Copyright 2022, John Wiley and Sons); (B) Contour plots of in-situ XRD patterns at various temperatures, and evolution of lattice parameters upon Na⁺ extraction (Reproduced with permission from Ref.^[80]. Copyright 2023, Elsevier); (C) Operando XRD patterns during the charge/discharge process in the voltage range of 1.5-4 V (vs. Na⁺/Na). Black asterisks represent peaks from Al window; Corresponding intensity contour maps (bird’s eye view) concerning the evolution of the main characteristic diffraction peaks (Reproduced with permission from Ref.^[100]. Copyright 2021, John Wiley and Sons); (D) In-situ synchrotron-based XRD patterns collected during the first cycle at 0.1 C, with the corresponding charge/discharge curve on the right; Intensity contour map and corresponding three-dimensional (3D) maps (Reproduced with permission from Ref.^[61]. Copyright 2020, John Wiley and Sons).