Fluorinated Nonflammable In Situ Gel Polymer Electrolyte for High-Voltage Lithium Metal Batteries

Rechargeable lithium metal batteries (LMBs) offer excellent opportunities for applications requiring high-energy-density battery systems. So far, it has received a lot of interest in pairing higher-energy-density high-voltage nickel-rich cathodes. Here, fluorinated solvents were used instead of the usual carbonate solvents to prepare gel polymer electrolytes (FGPE) by in situ polymerization of polymers introducing the fluorine-containing groups. Theoretically and experimentally, FGPE has proven to be ultra-compatible with the lithium metal anode and LiNi_0.8Co_0.1Mn_0.1O₂ cathode. A stable plating/stripping process of over 2000 h can be achieved for symmetrical lithium cells using FGPE. The Li||FGPE||NCM811 cell has a longer cycle life at a high voltage (4.5 V). In addition, the zero self-extinguishing time indicates that the FGPE has sufficient safety. In summary, the design of this electrolyte provides ideas to improve the safety and energy density of LMBs.