Highly\nAntioxidative Lithium Salt Enables High-Voltage\nEther Electrolyte for Lithium Metal Battery

Ether-based electrolytes\nexhibit excellent compatibility with Li\nmetal anodes, but their instability at high voltages limits their\nuse in high-voltage Li metal batteries. To address this issue, we\nintroduce an alternative perfluorobutanesulfonate (LiPFBS)/dimethoxyethane\n(DME) electrolyte to stabilize DME in a 4.6 V Li∥LCO battery.\nOur study focuses on the formation of solid-electrolyte interphase\n(SEI) and cathode-electrolyte interphase (CEI) layers compared with\nthe LiTFSI/DME electrolyte. We demonstrate that LiPFBS helps maintain\nDME’s compatibility in SEI formation. Additionally, a durable\nCEI layer derived from PFBS<sup>–</sup> enhances the performance\nof the cell at high voltages by forming a robust, inorganic-dominant\nCEI layer. A PFBS<sup>–</sup>-derived CEI significantly enhances\nthe overall performance of the full cell under high voltage conditions.