M-fluoroiodobenzene electrolyte additive with multifunctional groups for protecting lithium metal anode

Lithium metal battery can satisfy the demands of high energy density. The high reactive activity of fresh lithium metal results in lithium dendrite and 'dead lithium', hindering its further application. Herein, a simple but effective method, M-fluoroiodobenzene (CFI) electrolyte additive, is adopted to protect lithium metal anode. DFT calculation and XPS results prove the M-fluoroiodobenzene additive will prior to being adsorbed on lithium anode surface and constructing LiF-rich solid electrolyte interface (SEI) instead of solvent molecules. Electrochemical results further confirm that M-fluoroiodobenzene passivates the lithium anode interface by forming stable SEI and prevents severe side reactions of lithium metal with the electrolyte. SEM and in-situ optical visualization microscopy results prove that the additive indeed benefits the lithium dense deposition and reduces the loss of inactive lithium, which obviously improves the performances of batteries. It provides new insights into optimizing the lithium metal anodes with simple strategy from multiple aspects.