Manipulating Competitive Li Coordination of F-Rich Polymer and High Flash Point Glyme Electrolyte Enabling High Rate and Intrinsically Safe Quasi-Solid-State Li Metal Batteries.

Metal-based batteries incorporating quasi-solid gel electrolytes (QSEs) represent a promising approach to attain both high safety and high energy density. Nevertheless, the issues of limited ionic conductivity and insufficient solid-solid contact interfaces significantly impede their practical applications. In this study, an intrinsically safe QSE synthesized by in situ polymerizing trifluoroethyl acrylate (TFEA) in high flash point tetraglyme (G4)-based electrolyte is developed. Owing to the coordination between carbonyl oxygen atoms within the polymer matrix and Li, solvation cage caused by the "chelating" effect between Li and solvent molecules is disrupted. Molecular dynamic simulations reveal that a solvated structure predominantly characterized by the contact ion pair is formed. Therefore, a robust solid electrolyte interface enriched with anion-derived LiF- and B-species is constructed. As a result, matched with a commercial-level loading LiFePO cathode, a capacity retention of 92.7% is obtained even after 200 cycles. These results elucidate the polymer matrix's pivotal role in QSEs, offering novel pathway for designing advanced quasi-solid-state batteries, such as Li/Na/K/Mg/Ca et al.