Fig. 3: Operando impedance spectroscopy experiment during the first half cycle of Li metal stripping and plating on Li | |µAu | |Li three-electrode cell.
a Operando EIS spectra (black points, scale on top and right) and overpotential (red curve, scale on bottom and left) during stripping with LP40 electrolyte and 0.1 mA/cm2 current density. Symbols mark peak frequencies of the 1st, 14th and 27th spectrum and (b) plating during the same half cycle as in a). The red curves correspond directly to the values in Fig. S3e. The first value of the red curve is the overpotential value that was measured simultaneously with the first (high) frequency point (1 MHz) in the first impedance spectrum. The subsequent overpotential values were measured together with the last (low) frequency points (20 mHz) in the measured spectra. c, d The percentage contribution of Rel (dark grey area), RHF (light grey area), and RLF (white area, marked with blue arrow) resistance to the total resistance for stripping and plating, respectively. e Evolution over time of the electrolyte resistance (black lines), the high frequency arc resistance (red lines) and the low frequency resistance (blue lines) contributions for the whole cell. Contributions for the electrode undergoing striping are plotted in full lines and dots, contributions for the electrode undergoing plating are plotted in dotted lines and open circles. Note that the noise visible in d) is due to the instability of the ECE potential measurement during the three-electrode operando impedance experiment.
