Sodiophilicity and Sodium Metal Affinity Engineering Enable Stable Sodium Metal Anodes

Abstract The application of sodium metal anode is largely hindered by the volume change and dendrite growth during sodium metal plating/stripping processes. The construction of 3D structure and the introduction of sodiophilic sites can provide the hosts and uniform deposition sites for deposited sodium metal. Meanwhile, the nucleation sites of transition metals that can form an alloy with Na metal will further enhance the binding ability of the 3D framework to sodium metal, allowing sodium metal to better composite with the substrate. Therefore, this work designs a 3D bismuth‐decorated nitrogen‐doped carbon framework (Bi‐NCF) with optimization of sodiophilicity and sodium metal affinity. As a sodium metal anode to regulate the deposition behavior of Na metal on the electrode interface, this carbon framework effectively suppresses the volume change and dendritic growth during sodium metal plating/stripping processes. The half‐cell assembled by Bi‐NCF shows a low growth overpotential of sodium metal (3.3 mV at 0.5 mA cm −2 ) and high reversibility (Coulombic efficiency of 99.7% is maintained after 150 cycles at 2 mA cm −2 ), the symmetric cell stably deposits/strips sodium metal at a deep depth discharge of 85% for over 4500 hours. The assembled anode‐less full cell shows an excellent rate performance (31.3 mAh g −1 at 10 A g −1 ) and long‐term cycling stability (175 stable cycles with more than 80% capacity retention).