Enhancement of Lithium Anode Cycleability in Lithium Imide Electrolytes by an Additive Controlling an Anode Interface

Abstract

The addition of aluminum iodide (AlI₃) to binary electrolytes, propylene carbonate mixed with dimethyl carbonate (PC/DMC) or ethylene carbonate mixed with DMC (EC/DMC), containing lithium bis(perfluoroethylsulfonylimide) (LiBETI) improved the charge-discharge cycle efficiency of a Li metal anode; the enhanced efficiency in EC/DMC with LiBETI was about 95% even without the stacking pressure against the anode. In contrast, the AlI₃ addition reduced the efficiency in a PC/DMC electrolyte containing lithium hexafluorophosphate (LiPF₆). The AlI₃ additive in the LiBETI electrolytes provided a low-resistance Li interface without predominant anion-decomposition as well as dendritic or mossy Li deposition.