Counting lithium ions in the diffusion channel of an LiV2O4 crystal

As a new microscopic method to reveal lithium ion behavior in lithium ion batteries, we demonstrated that lithium atoms in the diffusion channel of the spinel structure (LiV2O4 crystal) were visualized and their number was countable one-by-one by using annular bright field imaging method in conjunction with a spherical aberration corrected electron microscope: the lithium column intensity varied by a step of single lithium atom in correlation with the thickness change of the LiV2O4 crystal, in accordance with theoretical image simulations.