摘要：SummaryThe structure of lithium (Li) metal anode, including the Li metal and the solid electrolyte interphase (SEI), is critical to the investigation of cycle stability or decay mechanisms. The three-dimensional (3D) visualization of Li metal and SEI, however, has not been demonstrated yet, owing to the lack of 3D characterization techniques and the susceptibility of Li metal anode toward oxygen, moisture, as well as electron beam. Herein, we introduce a successful 3D presentation of deposited Li metal and SEI established via low-dose cryogenic electron microscopy tomography. The Li metal anode is imaged in low-dose mode at different tilt angles and then aligned and reconstructed into a 3D image through an expectation-maximization algorithm. The spherical Li deposits and SEI are confirmed in the 3D tomography of Li metal anode. It is also discovered that the Li metal corrodes and SEI turns concave owing to possible self-discharge after long-time rest.Graphical abstractDisplay OmittedHighlights•We achieved 3D characterization of Li metal and SEI using cryo-STEM tomography•The uniformity and local thickness of the SEI can be accurately measured in 3D•The Li metal corrodes and turns concave due to self-discharge after depositionEnergy materials; Materials characterization; Materials characterization techniques; Materials chemistry; Materials science
