Weakly Solvating Cyclic Ether Electrolyte for High-Voltage Lithium Metal Batteries

The commercialization of high-voltage lithium (Li) metal batteries (LMBs) has been severely hindered due to the lack of advanced electrolytes that can simultaneously support a stable lithium metal anode (LMA) and high-voltage cathode (>4 V vs Li+/Li). Here, we propose a tetrahydropyran (THP)-based weakly solvating electrolyte (WSE) to regulate Li+ solvation structures and interfacial behaviors. The anion-rich Li+ solvation in THP-based WSE effectively promotes the formation of inorganic-rich solid electrolyte interphase (SEI) layers, firm cathode electrolyte interphase (CEI) films, and protective passivation films on an Al current collector. The optimized interfacial behaviors contribute to the highly compact Li deposition, high-voltage stability, and inhibition of transition metal ion dissolution and Al corrosion. Finally, the Li||LiNi0.5Co0.2Mn0.3O2 full cell delivered stable cycling performance at high cutoff voltages of 4.3 and even 4.5 V. This study demonstrates an exciting approach to enable ether-based electrolytes for high-voltage LMBs and could be developed for other battery systems.