Widening electrochemical window of ether electrolyte via solvent-diluent intermolecular interactions for high-voltage lithium metal batteries

Ether-based electrolytes exhibit excellent compatibility with lithium metal anodes but suffer from poor oxidation stability when paired with high-voltage cathodes. Although the localized high-concentration (LHCE) electrolyte strategy has partially expanded the operational voltage window by modulating anion coordination and incorporating fluorinated diluents, the intrinsic susceptibility of ether solvents to decomposition remains unresolved. Herein, we turn our attention to the potential interactions between solvents and diluents, and identify solvent- diluent complexes through electrostatic potential screening. Within these complexes, intermolecular interaction effectively inhibits electron transfer between the solvent and the cathode. Moreover, the diluent actively draws the solvent away from highly reactive electrode interface, forming a weakly adsorbed configuration that substantially suppresses oxidative decomposition. Electrochemical evaluations demonstrate that a LiN_0.9Co_0.05Mn_0.05O₂||Li cell retains 72.2% of its initial capacity after 200 cycles (compared to 33.0% for counterpart) within 2.8–4.5 V, and maintains stable operation over 200 cycles under harsh conditions (2.8–4.5 V, 45 °C). Assembled pouch-type cells deliver a capacity retention of 88.5% after 400 cycles, versus 80.8% for counterpart. This work provides a new perspective for selecting compatible solvents and diluents within the LHCE framework, aiming to enhance electrolyte oxidation stability from the perspective of solvent itself. © 2026 Elsevier B.V.