A Fluidic and Sodiophilic Liquid Metal Current Collector for Dendrite‐Free and Stable Anode‐Free Sodium Metal Batteries

ABSTRACT Anode‐free sodium metal batteries (AFSMBs) have garnered significant interest due to their potential to achieve the highest possible energy density among sodium‐based battery systems. However, the high nucleation energy barrier of Na + on conventional current collectors leads to uneven Na deposition and dendrite growth, posing a great challenge to stable device operation. Herein, a scalable modified current collector (LM@Cu) is constructed by leveraging the intrinsic fluidity and sodiophilicity of a Ga‐In‐Sn liquid metal (LM) to realize dendrite‐free Na deposition and stable operation of AFSMBs. During charging, the alloying reaction between LM and Na effectively reduces the nucleation barrier, promotes uniform Na deposition, suppresses dendrite growth, and minimizes the generation of dead Na. This mechanism facilitates highly reversible Na plating and stripping, substantially extending the cycle life of AFSMBs. Moreover, a thin NaF‐rich solid electrolyte interphase is formed, which facilitates Na + transport and enhances interfacial stability. Consequently, AFSMBs constructed with LM@Cu and Na 3 V 2 (PO 4 ) 3 cathode achieve a capacity retention of ∼80% after 100 cycles, significantly outperforming cells based on Cu current collector, which fail within 30 cycles. This work provides a promising strategy for realizing dendrite‐free and stable AFSMBs.