Liquid Metal‐Modified 3D Cu Foam for Dendrite‐Free Sodium Plating

Abstract Sodium metal is regarded as one of the most promising anode materials due to its high theoretical capacity (1166 mAh g −1 ) and low redox potential (−2.714 V vs standard hydrogen electrode). However, the practical application of sodium metal is hindered by the formation of dendrites during Na stripping and plating, which can degrade performance and cause potential safety hazards. To address this issue, previous work focuses on leveraging either 3D current collectors or liquid metal modification on current collectors. In this work, both strategies are simultaneously leveraged to design a 3D Cu foam with liquid metal modification (LM@Cu) for dendrite‐free sodium plating. The 3D configuration of Cu effectively reduces local current density and evenly distributes electric fields, while the introduction of liquid metal enhances the sodiophilicity of Cu to lower the nucleation barrier for sodium, thereby promoting its uniform plating. As a result, symmetric cells of Na with LM@Cu maintain stable cycling for over 2800 h. Additionally, full cells comprising Na‐LM@Cu and Na 3 V 2 (PO 4 ) 3 sustain 97.5% of the capacity upon 1000 cycles, underscoring the great potentiality of liquid metal‐mediated 3D current collectors in energy storage.