Figure 5: Electrochemical characterization of the electrodes for lithium deposition/dissolution.

(a) Coulombic efficiency of the cells versus cycle number using electrolytes containing different concentrations of Li₂S₈ at a current density of 2.0 mA cm⁻² with a constant lithium deposition capacity of 2.0 mAh cm⁻² (the LiNO₃ additives in these electrolytes are all 1 wt%, ∼0.15 M). (b–d) Cycling performances of the cells using electrolyte containing 0.18 M Li₂S₈ and 5 wt% LiNO₃ (∼0.75 M, close to the saturation concentration of LiNO₃ in 1,3-dioxolane/1,2-dimethoxyethane (DOL/DME) electrolyte) at a current density of 2.0 mA cm⁻² with a deposition capacity of 1, 2 and 3 mAh cm⁻², respectively. The hollow symbols represent data of the control samples using electrolyte with 5 wt% LiNO₃. Comparison of (e) voltage profiles and (f) average voltage hysteresis of the lithium deposition/dissolution process with lithium metal as the reference/counter electrode at 2 mA cm⁻² using electrolyte containing only LiNO₃ (5 wt%) (black line/square) and containing both Li₂S₈ (0.18 M) and LiNO₃ (5 wt%) (red line/square). The voltage profiles are obtained at the second cycle of lithium deposition/dissolution. PS, lithium polysulfide (Li₂S₈).