Synergistic Coupling of Li6.4la3zr1.4ta0.6o12 and Fluoroethylene Carbonate Boosts Electrochemical Performances of Poly(Ethylene Oxide)-Based All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) with poly(ethylene oxide) (PEO)-based composites solid-state electrolyte have received much attention in the field of energy storage and conversion owing to their higher energy density and better safety as compared with conventional liquid electrolytes. However, ASSLBs with PEO-based solid-state electrolytes generally suffer from severe capacity degradation and interface transfer obstacle during the change/discharge process. In this work, fluoroethylene carbonate (FEC) is employed as reducing additive to in-situ form LiF-rich and stable solid-state electrolyte interface (SEI). Additionally, active ceramic Li6.4La3Zr1.4Ta0.6O12 (LLZTO) is selected to inhibit the crystallization of PEO, thus improving the ionic conductivity and mechanical strength. Benefiting from the integrated advantages of LLZTO and FEC binary additives, the number of lithium-ion transference increases to 0.48, which facilitates the stable cycling of Li||Li symmetrical batteries over 900 h at 0.1 mA cm-2. Meanwhile, the capacity retention of LiFePO4||Li batteries increases to 93.6% after 100 cycles at 60 °C. The synergistic interplay of LLZTO and PEO constructs a stable LiF-rich SEI film, effectively addressing the interfacial problems caused by lithium dendrites, and also promoting the transport of Li+. Therefore, the high ionic conductivity and self-healing anode-electrolyte interface are achieved. This study provide a facile and economical strategy to solve the problem of lithium anode-electrolyte interface. It is of great scientific significance for the development of dendrite-free solid-state lithium metal batteries.