Working toward fluoride batteries Owing to the low atomic weight of fluorine, rechargeable fluoride-based batteries could offer very high energy density. However, current batteries need to operate at high temperatures that are required for the molten salt electrolytes. Davis et al. push toward batteries that can operate at room temperature, through two advances. One is the development of a room-temperature liquid electrolyte based on a stable tetraalkylammonium salt–fluorinated ether combination. The second is a copper–lanthanum trifluoride core-shell cathode material that demonstrates reversible partial fluorination and defluorination reactions. Science, this issue p. 1144 Fluoride ion–conducting liquid electrolytes enable room-temperature cycling of fluoride ion electrochemical cells. Fluoride ion batteries are potential “next-generation” electrochemical storage devices that offer high energy density. At present, such batteries are limited to operation at high temperatures because suitable fluoride ion–conducting electrolytes are known only in the solid state. We report a liquid fluoride ion–conducting electrolyte with high ionic conductivity, wide operating voltage, and robust chemical stability based on dry tetraalkylammonium fluoride salts in ether solvents. Pairing this liquid electrolyte with a copper–lanthanum trifluoride (Cu@LaF3) core-shell cathode, we demonstrate reversible fluorination and defluorination reactions in a fluoride ion electrochemical cell cycled at room temperature. Fluoride ion–mediated electrochemistry offers a pathway toward developing capacities beyond that of lithium ion technology.

中文翻译：

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金属氟化物电极的室温循环：用于高能氟离子电池的液体电解质

致力于氟化物电池 由于氟的原子量低，可充电氟化物电池可以提供非常高的能量密度。然而，当前的电池需要在熔盐电解质所需的高温下运行。戴维斯等人。通过两次进步，推动可在室温下工作的电池。一个是基于稳定的四烷基铵盐-氟化醚组合的室温液体电解质的开发。第二种是铜-三氟化镧核壳阴极材料，它展示了可逆的部分氟化和脱氟反应。科学，这个问题 p。1144 氟离子导电液体电解质可实现氟离子电化学电池的室温循环。氟离子电池是具有高能量密度的潜在“下一代”电化学存储设备。目前，此类电池仅限于在高温下运行，因为合适的氟离子导电电解质仅在固态下为人所知。我们报告了一种基于干燥的四烷基氟化铵盐在醚溶剂中的具有高离子电导率、宽工作电压和强大化学稳定性的液态氟离子导电电解质。将该液体电解质与三氟化铜-镧（Cu@LaF3）核壳阴极配对，我们证明了在室温下循环的氟离子电化学电池中的可逆氟化和脱氟反应。氟离子介导的电化学为开发超越锂离子技术的能力提供了途径。