Fig. 7. Influence of naked Li surface on the deposition layer.

a Photographs of the naked (left) and pristine (right) Li metal foils after 100^th Li plating. Cycling conditions: 1 mA cm⁻², 1 mAh cm⁻². b SEM images of the active Li layer (left) on the previously naked Li metal foil and the dead Li layer (right) on the previously pristine Li metal foil after 100 cycles at 1 mA cm⁻² with 1 mAh cm⁻². c Schematic illustration of layer of columnar Li deposit grown on the naked Li foil. d Exchange current density of the naked (red) and pristine (black) Li-Li symmetric cells before (dashed line) and after (solid line) 100 cycles at 1 mA cm⁻² with 1 mAh cm⁻². e Reconstructed XTM images of the naked Li metal foil after 100 cycles at 1 mA cm⁻² with 1 mAh cm⁻².