Room-temperature sodium metal batteries with metallic Na anodes and flammable organic solvent-based electrolytes are breeding severe safety concerns. Herein, by introducing non-flammable, highly-fluorinated ethers as bridge solvents, we enable superior miscibility of an all-fluoride fire extinguishant into fluorinated carbonate electrolytes. Besides the intrinsic non-flammability of the designed electrolyte, the embedded PFMP extinguishant further enhances the battery safety by its efficacy to in situ dissipate the internal heat at an elevated temperature (ΔH = +88.1 J g⁻¹). Moreover, the cyclability is greatly improved by using such an electrolyte. The Na/Na symmetrical cells can cycle for 1100 h at 1.0 mA h cm⁻² and more than 800 h at 5.0 mA h cm⁻². Paired with a high voltage Na₃V₂(PO₄)₂O₂F cathode, the full cell exhibits a high initial coulombic efficiency of 94.7% and a capacity retention of 87.1% after 1000 cycles at 0.5C, which is mainly ascribed to the thin F-rich interphases established on both the Na metal anode and the cathode.

中文翻译：

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将全氟化物灭火剂与高氟化电解质的不混溶性桥接到安全的钠金属电池上

具有金属Na阳极和易燃有机溶剂基电解质的室温钠金属电池正在引发严重的安全隐患。在此，通过引入不易燃的高度氟化的醚作为桥溶剂，我们使全氟化物灭火剂与氟化碳酸盐电解质具有优异的混溶性。除了所设计的电解质固有的不可燃性之外，嵌入式PFMP灭火剂还具有在高温下（ΔH = +88.1 J g ^-1）原位散发内部热量的功效，从而进一步提高了电池安全性。而且，通过使用这种电解质，可循环性大大提高。Na / Na对称电池可在1.0 mA h cm ^{-2的条件下}循环1100 h在5.0 mA h cm ^-2时超过800 h 。与高电压Na ₃ V ₂（PO ₄）₂ O ₂ F阴极配对后，整个电池在0.5C的温度下经过1000次循环后，具有94.7％的高初始库仑效率和87.1％的容量保持率。在钠金属阳极和阴极上都建立了富F的薄相。