A Highly Reversible, Dendrite-Free Lithium Metal Anode Enabled by a Lithium-Fluoride-Enriched Interphase.

Metallic lithium is the most competitive anode material for next-generation lithium (Li)-ion batteries. However, one of its major issues is Li dendrite growth and detachment, which not only causes safety issues, but also continuously consumes electrolyte and Li, leading to low coulombic efficiency (CE) and short cycle life for Li metal batteries. Herein, the Li dendrite growth of metallic lithium anode is suppressed by forming a lithium fluoride (LiF)-enriched solid electrolyte interphase (SEI) through the lithiation of surface-fluorinated mesocarbon microbeads (MCMB-F) anodes. The robust LiF-enriched SEI with high interfacial energy to Li metal effectively promotes planar growth of Li metal on the Li surface and meanwhile prevents its vertical penetration into the LiF-enriched SEI from forming Li dendrites. At a discharge capacity of 1.2 mAh cm , a high CE of >99.2% for Li plating/stripping in FEC-based electrolyte is achieved within 25 cycles. Coupling the pre-lithiated MCMB-F (Li@MCMB-F) anode with a commercial LiFePO cathode at the positive/negative (P/N) capacity ratio of 1:1, the LiFePO //Li@MCMB-F cells can be charged/discharged at a high areal capacity of 2.4 mAh cm for 110 times at a negligible capacity decay of 0.01% per cycle.