Terminally fluorinated ether as a solvent for high-performance lithium metal battery electrolyte

Terminally fluorinated ether 5FDEE shows exceptional compatibility with LiPF₆, enabling high-performance Li-metal batteries. Li‖NMC811 cells with a 1 M LiPF₆ in 5FDEE : FEC (9 : 1 v/v) electrolyte demonstrate remarkable cycling stability with an average coulombic efficiency exceeding 99.9% and no capacity fading over 550 cycles at 2.7-4.3 V vs. Li⁺/Li.