In situ scanning vibrating electrode technique for lithium metal anodes

The effect of the inorganic additives to electrolytes, aluminum iodide (AlI3) and tin (II) iodide, on the charge/discharge coulombic efficiency of a lithium (Li) metal anode has been investigated in binary solvent systems, i.e., propylene carbonate (PC) mixed with 2-methyltetrahydrofuran (2Me-THF) containing lithium perchlorate (LiClO4), PC + 2Me-THF/LiClO4, and PC mixed with 1,2-dimethoxyethane (DME) containing LiClO4, PC + DME/LiClO4. AlI3 improved the coulombic efficiency of the Li metal anode in both the binary solvent systems. Two-dimensional Li ionic currents at the interface of the Li metal anode were monitored by using in situ scanning vibrating electrode technique (SVET) in the representative binary system, PC + 2Me-THF/LiClO4, in the absence and presence of the additives. The relationship between the coulombic efficiency and the Li ionic current distribution on the anode was discussed.