Investigating microstructure evolution of lithium metal during plating and stripping via operando X-ray tomographicmicroscopy

Li metal is considered as the most important negative electrode active material for Li-based batteries because of its high theoretical specific capacity of 3860mAh g-1, which is an order of magnitude higher than the currently used graphite, and by being the most electropositive metal. When coupled with high-capacity cathodes, either Li insertion materials or conversion chemistries, or applied in a solid-sate configuration, a leap in energy density can be obtained. The main challenge in the direct utilization of Li metal as anode is the formation of a mossy and dendritic morphology upon cycling manifested in a low Columbic efficiency and a continuous consumption of the electrolyte through parasitic side reactions, continuous growth of the solid electrolyte interphase (SEI) and irreversible capacity loss on the anode. These issues are a result of processes taking place both during charge (Li plating) and discharge (Li stripping), creating an unstable electrode structure.