Electrodes were harvested from Cu|Li cells cycled at 4.0 mA cm−2 with a 4-M LiFSI-DME electrolyte after: (a) 1st cycle. (b) 100th cycle. (c) 200th cycle. Columns I and II are, respectively, for optical images of Cu and Li electrodes at different cycle numbers, while Columns III and IV show the SEM images of the cross-section and surface morphologies of Li metal anode. The diameter of the Cu substrate shown in Column I and II was 2 cm. The scale bars for Columns III and IV are 100 and 10 μm, respectively.