CHARGE/DISCHARGE PERFORMANCE OF A Li METAL ANODE IN CARBONATE-TYPE BINARY ELECTROLYTES WITH METAL SALT ADDITIVES

摘要

The effect of inorganic additives to electrolytes, aluminum iodide (AlI_3) and tin (II) iodide (SnI_2), on charge-discharge coulombic efficiency of a lithium (Li) metal anode has been investigated in binary solvent systems, i.e., propylene carbonate (PC) mixed with dimethyl carbonate (DMC) containing lithium perchlorate (LiClO_4), PC+DMC/LiClO_4, and ethylene carbonate (EC) mixed with DMC containing LiClO_4, EC+DMC/LiClO_4. AlI_3 improved the coulombic efficiency of the Li metal anode in both the binary solvent systems while no obvious improvement of the efficiency was observed for the electrolyte systems with SnI_2. The relationship between the coulombic efficiency and ac impedance behavior of a Li anode interface in the presence of the additives is discussed.