Fig. 5: Electrochemical test results of symmetric cells.

a Chronopotentiometry measurements of the pristine (black) and naked (red) Li-Li symmetric cells at a current density of 1 mA cm⁻². b Cell failure time for the pristine (black) and naked (red) Li-Li symmetric cells during chronopotentiometry measurements at various current densities. The dashed line indicates the theoretical depletion time of the Li metal counter electrode with the thickness of 300 μm at each current density. c Nyquist plots of the pristine (black) and naked (red) Li-Li symmetric cells before galvanostatic cycling. Galvanostatic charge-discharge voltage profiles of the pristine (black) and naked (red) Li-Li symmetric cells with operating conditions of d 1 mA cm⁻², 1 mAh cm⁻², e 10 mA cm⁻², 1 mAh cm⁻², f 3 mA cm⁻², 3 mAh cm⁻², and g 5 mA cm⁻², 3 mAh cm⁻². Electrolytes: 1 M LiPF₆ in EC/DEC (50/50 = v/v) with 10 wt % FEC for d−f, and 5.5 M LiFSI in DMC for g.