Fig. 2
From: Environmentally stable interface of layered oxide cathodes for sodium-ion batteries
Oxidation state, composition, and crystalline phase of the local fine structure of the NMTN samples. a HADDF-STEM and EELS mapping images focusing on the Ti and O composition and chemical shift from the core to the shell for a typical location; the numerical marks indicate the selective spots for EELS. b Energy-loss near-edge spectrum (ELNES) of the Ti-L2,3 (vertical brown shading) and O-K (vertical blue shading) edges, wherein the yellow dotted lines show peak A and peak C of the O-K edges. c Chemical composition of Ti and O, in which the vertical yellow shading represents the location of the interface; d STEM-HADDF image, indicative of the zigzag phase boundary; scale bar, 1 nm. e Magnified image extracted from the blue rectangle of d, assigned to the typical layered stacking in the bulk; scale bar, 0.5 nm. f Magnified image extracted from the red rectangle of d, showing the spinel-like stacking at the interface; scale bar, 0.5 nm
