Spatially decoupled fluorinated-ether–ester electrolytes for extreme-condition lithium metal batteries

Abstract

Traditional ether-based electrolytes of Lithium metal batteries (LMBs), while enabling stable lithium deposition and low-temperature operation, suffer from insufficient oxidative stability under extreme conditions. Here, we propose a spatially decoupled solvation-shell strategy to construct weakly oriented fluorinated-ether–ester hybrid electrolytes with outer-shell fluorination protection. A spatially decoupled solvation structure is constructed where ether dominates the inner shell for stable Li⁺ coordination, while fluorinated solvents form an oxidation-resistant outer shield. The long-chain anion-coordinated cluster complexes redirect decomposition pathways, enriching both anode and cathode interfaces with LiF and Li₃N, enhancing interfacial stability and Li⁺ transport. Fluorine-induced interactions disrupt solvent ordering, while fluorinated CEI/SEI layers mitigate dendrite growth and cathode degradation. The Li||LiNi_0.8Co_0.1Mn_0.1O₂ full cell retains 85.2% capacity after 100 cycles at −20 °C and 4.5 V. The work establishes a spatially decoupled solvation-shell paradigm for simultaneously addressing thermodynamic and kinetic challenges in extreme-condition energy storage systems.