Fig. 2. Electrochemical behavior upon Li plating and stripping at 25 °C.

a Potential response upon plating 5 mAh cm⁻² of Li onto a Cu current collector at 0.05 mA cm⁻² and then subsequently stripping at 0.05 mA cm⁻². b The Coulombic efficiency of Li plating and stripping of 3 mAh cm⁻² of Li as a function of cycle number. The potential profiles are shown in Supplementary Fig. S1. c A comparison of the impedance spectra before and after the first Li plating and stripping cycle.