Probing the Formation of Lithium Metal in an Inert Atmosphere by Big Data-Driven In Situ Electron Microscopy

The high chemical reactivity of lithium slows down the structural exploration of lithium metals inside batteries. In this paper, in situ gas cell TEM was utilized to study the formation and growth of lithium metal under the argon atmosphere. By electron irradiation, fresh lithium metals could be formed and grown from lithium salts such as lithium fluorides, which was confirmed by electron diffraction and EELS. Minor oxidation of the as-grown lithium metals occurred even in an inert environment. A template matching-based diffraction big-data analysis method was developed and enabled visualization of the phase evolution during the reactions. These results may provide additional understanding of the passivation layers on lithium, and big data processing would facilitate information mining from in situ experiments.