STEM images and EEL spectra of Li4-x2Ti5O12-y2 under 2.7 V. (a) ABF and (b) HAADF images of the oxygen-vacancy ordered Li-deficient LTO. (c) Enlarged ABF image from the red frame in (a). (d) Line profile of inversed ABF contrast along the [Ti-b]-[Ob]-[Ti-b] chain. (e) Ti L edges and (f) O K edge of O1 sites and O2 sites, which are normalized by peak a. Scale bar: 1 nm.