fig4

Figure 4. Morphological evolution and Na⁺ storage kinetics of HEO424 and NFM424 cathodes after 200 cycles. (A-D) SEM and HAADF-STEM images of the cycled electrodes. (E and F) Intensity profiles along the designated lines in (C) and (D). (G and H) Schematic diagrams illustrating the structural changes in HEO424 and NFM424. (A-H) Reproduced with permission^[105]. Copyright 2022, American Chemical Society. HT-XRD patterns (30 °C to 400 °C) and contour maps of (I and K) charged HENM and (J and L) charged NM electrodes. Hy. = hydrated phase, L. = layered structure, and R. = rock salt phase. HAADF-STEM images of (M and O) NM and (N and P) HENM after 50 cycles at different magnifications. (Q) GPA analysis of the HENM cathode. (I-Q) Reproduced with permission^[106]. Copyright 2025, American Chemical Society. SEM: Scanning electron microscope; HAADF-STEM: high-angle annular dark-field scanning transmission electron microscopy; HT-XRD: high-temperature X-ray diffraction; HENM: high-entropy Na_xTMO₂; NM: Na_xTMO₂; GPA: geometric phase analysis.