Regulating Solvating Sites for Stable High-voltage Lithium Metal Batteries.

Abstract

The long-lasting stability of high-voltage lithium metal batteries (LMBs) critically rely on both the cathodic and anodic stability of electrolytes, which can be enhanced by increasing the salt-to-solvent molar ratio. However, this approach is limited by solubility constraints. In this work, we introduce a dual-anchoring strategy to regulate the solvating sites of glymes via directional atomic interactions. Specifically, Fδ--Hδ+ interactions transform the Li+-glyme coordination and induce more anion coordination within Li+ primary solvation sheath while Hδ+-Oδ- interactions reduce the electron density at free oxygen sites, thus raising the oxidational potential of glyme and enhancing the overall oxidation stabiltiy of electrolytes. This strategy results in an electrolyte with exceptional compatibility with both lithium metal anode (LMA) and high-voltage cathode, enabling LMA with an ultrahigh Coulombic efficiency (CE) of 99.76%. Furthermore, the assembled LMBs exhibit extended lifespans, retaining 80% of their capacity under aggressive conditions: 834 and 370 cycles at 4.4 V and 4.5 V, respectively, for 30-μm-Li||2.0-mAh cm-2 LiNi0.8Co0.1Mn0.1O2 cells, and 100 cycles for anode-free Cu||LiNi0.5Co0.2Mn0.3O2 pouch cells. This work offers novel insights into the advancement of next-generation LMBs based on ether-based electrolytes.