Functionalizing Separator by Coating a Lithiophilic Metal for Dendrite‐Free Anode‐free Lithium Metal Batteries

Abstract A stable anode‐free lithium metal battery (AFLMB) is accomplished by the adoption of a facile fabricated amorphous antimony (Sb)‐coated separator (SbSC). The large specific surface area of the separator elevates lithium (Li)‐Sb alloy kinetic, improving Li wetting ability on pristine copper current collector (Cu). When tested with LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) as cathode, the full cell with SbSC demonstrates low nucleation overpotential with compact, dendrite‐free and homogeneous Li plating, and exhibits a notable lithium inventory retention rate (LIRR) of 99.8 % with capacity retention of 93.6 % after 60 cycles at 0.5 C‐rate. Conversely, full cells containing pristine separator/Cu (i. e., SC) and pristine separator/Sb‐coated current collector (i. e., SSbC) display poor cycling performances with low LIRRs. Density functional theory corroborates the nucleation behaviours observed during in‐situ half‐cell Li deposition. Functionalizing polymeric separator by metallic coating in AFLMB is a novel approach in improving the cycle life of an AFLMB by promoting homogeneous Li plating behavior. This innovative approach exemplifies a promising applicability for uniform Li‐plating behavior to achieve a longer cycle life in AFLMB.