Intermolecular Interactions Mediated Nonflammable Electrolyte for High‐Voltage Lithium Metal Batteries in Wide Temperature

Abstract

AbstractHigh‐voltage lithium metal batteries are the most promising energy storage technology due to their excellent energy density (>400 Wh kg−1). However, the oxidation decomposition of conventional carbonate‐based electrolytes at the high‐potential cathode, the detrimental reaction between the lithium anode and electrolyte, particularly the uncontrolled lithium dendrite growth, always lead to a severe capacity decay and/or flammable safety issues, hindering their practical applications. Herein, a solvation structure engineering strategy based on tuning intermolecular interactions is proposed as a strategy to design a novel nonflammable fluorinated electrolyte. Using this approach, this work shows superior cycling stability in a wide temperature range (−40 °C to 60 °C) for a 4.4 V‐class LiNi0.8Co0.1Mn0.1O2 (NCM811)‐based Li‐metal battery. By coupling the high‐loading of NCM811 cathode (3.0 mAh cm−2) and a controlled amount of lithium anode (twofold excess of Li deposition on Cu, Cu@Li) (N/P = 2), the Cu@Li || NCM811 full cell can cycle more than 162 cycles with high‐capacity retention of 80%. This work finds that the change of the coordination environment of Li+ with solvent and PF6− by tuning intermolecular interaction is an effective method to stabilize the electrolyte and electrode performance. These discoveries can provide a pathway for electrolyte design in metal ion batteries.