fig13

Figure 13. (A) In-situ observation of a micro-electro-mechanical system device nanochip using the focused ion beam to apply the electric field (from left to right are the anode, SSE and cathode) and the (B) corresponding schematic. (C) Annular bright-field (ABF) and (D) high-angle annular dark-field (HAADF) images of a pristine cathode annular. The corresponding line profile acquired at the red dashed line rectangular zone is shown in panel (C) with both lithium and oxygen contrast. Lithium, oxygen and cobalt ions are represented as green, purple and cyan balls, respectively, in panels (B) and (C). (E) HAADF image of the delithiated cathode colored in blue using the GPA method and two orientations colored with green and red. Panels (F) and (G) are zoomed-in micrographs of the yellow, dashed-line, rectangular area. Panels (H) and (I) are zoomed-in micrographs of the pink, dashed-line, rectangular area. For both boundaries, a contrast in the lithium layer in both the HAADF and the ABF micrograph is shown, suggesting heavy atoms are present in the lithium layer. The basal planes of the two crystals that meet at an angle of 112° are shown in panels (F) and (G) (reproduced with permission from^[201]).