A Comparison of Carbonate-Based and Ether-Based Electrolyte Systems for Lithium Metal Batteries

Electrolytes play a critical role in enabling the stable cycling of rechargeable lithium (Li) metal batteries. While carbonate-based and ether-based electrolytes are widely investigated respectively with notably improved electrochemical performances in Li metal batteries, few works have been conducted for systematical understanding and comparison of these two systems. Here, we side-by-side investigated carbonate-based (dimethyl carbonate, DMC) and ether-based (1,2-dimethoxyethane, DME) electrolyte systems in terms of cathodic chemical/electrochemical stabilities, anodic stability, transport properties, Li morphology, Coulombic efficiency, and full cell performances. The experimental results indicate that ether-based electrolyte systems exhibit all-around superior compatibilities with Li metal anode, although the carbonate-based systems can be significantly improved from the commercial baseline by introducing fluorinated co-solvent. The ether-based systems, even at low concentrations, demonstrate acceptable anodic stability when charged to a reasonable cut-off voltage in practical applications. This work sheds light on advanced electrolyte development toward practical Li metal batteries.