LAUSR

Although gel polymer electrolyte (GPE) is one of the promising candidates to address the individual limitations of liquid and solid electrolytes, the extensively development is still hindered due to the veiled Li ions conduction mechanism. Herein, the related mechanism in GPE is extensively studied by developing an in-situ polymerized GPE comprising fluoroethylene carbonate (FEC) solvent and carbonate ester segments (F-GPE). Practically, although with high dielectric constant, FEC is fail to effectively transport Li ions when acts as the sole solvent. By sharp contrast, F-GPE demonstrates superior electrochemical performances and the related Li ions transfer mechanism is investigated using molecular dynamics simulations and 7 Li/6 Li solid state nuclear magnetic resonance spectroscopy. The polymer segments are extended with the swelling of FEC, then an electron delocalization interface layer is generated between abundant electron-rich groups of FEC and polymer ingredients, which works as an electron-rich "Milky Way" and facilitates the rapid transfer of Li ions by lowering the diffusional barrier dramatically, resulting in a high conductivity of 2.47  ×  10-4  S cm-1 and a small polarization of about 20 mV for Li//Li symmetric cell after 8000 h. Remarkably, FEC ingredient provides high flame-retardancy and make F-GPE remains stable under ignition and puncture tests. This article is protected by copyright. All rights reserved.