Fig. 2. Homogenous distribution of Li and the layered structure in NCM-pristine.

a APT depth profile showing a homogeneous distribution of the constituent elements, including Li, along the depth. b APT 3D ion map of Li (red), Ni (green), Co (violet), Mn (orange), O (blue), respectively, showing no elemental segregation. Error bars show the standard deviation of each dataset. c, d STEM-HAADF images along [$1\overline{1}0$] zone axis. A layered structure is clearly observed both at the surface (c) and in the interior (inset: magnified image) (d). e HAADF intensity profile along the region enclosed by the dotted square in (d), which shows the absence of TM migration.