A High‐Voltage Lithium‐Metal Batteries Electrolyte Based on Fully‐Methylated Pivalonitrile

Abstract Nitrile‐based electrolytes with high‐voltage have emerged as attractive candidates for high energy intensive lithium‐metal batteries (LMBs). But they are still hampered by the inherent instability of reductive lithium anodes. Herein, we propose a fully methylated pivalonitrile (PN) as a stable electrolyte solvent for LMBs. This nitrile‐based electrolyte achieves a wide electrochemical window and desired compatibility towards LMB, the assembled Li||Li symmetric cells can achieve satisfying electrochemical performance with low overpotential and high durability (500 h). The uniform and dense Li deposition investigated by operando monitoring during the Li metal plating process reveals the high Coulombic efficiency (CE) and long‐term durability. Furthermore, the full cell coupled with LiNi 0.6 Mn 0.2 Co 0.2 O 2 using this optimized electrolyte displays enhanced capacity retention (75.3 % after 300 cycles at 1 C) together with better stability and less CO 2 gas production. This study provides new insights in the development of high safety electrolytes and promotes the practical application of high‐voltage lithium‐metal batteries.