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

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_0.8Mn_0.1Co_0.1O₂ (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.