Figure 2

(a) Cyclic voltammograms of Ca plating/stripping after conditioning cycles at 20 mV s⁻¹ with a three electrode setup using Au as the working electrode and Ca as the reference and counter electrodes at room temperature. Cyclic voltammograms for initial three cycles as conditioning processes are shown in Fig. S6. (b) Coulombic efficiency determined from the cyclic voltammograms. Inset: charge balance for cycles 4–10.