Fig. 5.

Morphologies of Li metal anodes after cycling. a Schematic illustration of symmetric cell structure consisting of Li metal electrodes based on E-Cu and P-Cu with a Li metal foil counter electrode. b Surface top-view SEM image of E-Cu after cycling for 150 cycles at 0.5 mA cm⁻²; the inset is the magnified image of the edge of the pinholes in the PI film from the selected area in a. c Overview SEM image of P-Cu after cycling. d Overview SEM image of E-Cu after peeling off the upper PI film. e Magnified overview SEM image of P-Cu after cycling. The scale bars in b, c, d and e are 50 μm, 2 μm, 50 μm and 500 nm, respectively. The scale bar in the inset of b is 10 μm