Fig. 4.

Characterizations of cycled Li metal anodes. Ar⁺-sputtering XPS profiles of SEI layers on Li metal surfaces from a Li|PVH|Li and b Li|PVH-IM|Li cells after cycling for 50 h at 0.1 mA cm⁻². ToF–SIMS results of SEI layers on Li metal surfaces from Li|PVH|Li and Li|PVH-IM|Li cells after cycling for 50 h at 0.1 mA cm⁻²: c depth profiles and d 3D reconstruction images. SEM images of Li metal anode surfaces from e Li|PVH|Li and g Li|PVH-IM|Li cells after cycling for 50 h at 0.1 mA cm⁻². In situ optical microscope images of f Li|PVH|Li and h Li|PVH-IM|Li cells during Li plating. The scale bars in f and h are 1 mm