Atomic structure of Li4Ti5O12 and its in-situ experiment setup. (a) Structural schematics of Li4Ti5O12 and the projection along the <110> direction. Ti columns with different projection density are labeled with Ti-a and Ti-b, the neighbored oxygen columns are also labeled with Oa and Ob, respectively. (b) In-situ setup for constructed batteries where Li4Ti5O12 serves as positive electrode, the LLZO acts as the electrolyte and Si as the counter-electrode. (c, d) HAADF and ABF images of Li4Ti5O12 viewed along the <110> direction, the Ti, O and Li columns have been identified at atomic scale. Scale bar: 1 nm.