Stable Dendrite-Free High-Voltage Lithium Metal Batteries Enabled by Localized High Concentration Fluoroethylene Carbonate Based Electrolytes

Lithium-metal anode has been considered as the Holy Grail anode to achieve high-energy-storage batteries. However, significant challenges still exist in developing the highly stable electrolytes for Li-metal anodes and high-voltage cathodes. In this work, a localized high-concentration electrolyte (LHCE, 1.48 M FEC/EMC/HFE-LiDFOB) is proposed to realize stable dendrite-free cycling with excellent ca. 85% capacity retention and >99.5% Coulombic efficiency (CE) in LiNi0.6Co0.2Mn0.2O2 (NCM622) batteries at 0.5 C after 150 cycles. The cycling stability is largely improved, which can be associated with the formation of the robust solid electrolyte interphase layer on Li-metal anode owing to the preferential decomposition of LiDFOB salt and fluoroethylene carbonate solvent molecules. This study greatly expands knowledge of LHCE and provides a perspective of electrolyte design to achieve high-energy-density LMBs.