Synergistic Effect of Mesoporous Carbon‐Based Framework with Sodiophilic Nanoparticles for Stable Sodium Metal Anodes

Abstract Sodium metal anodes (SMAs), featuring high theoretical specific capacity and low redox potential, offer a feasible approach toward next‐generation high‐dense energy storage technology. However, the growth of Na dendrite and the sluggish kinetics of ion transport remain severe challenges for the practical use of SMAs. Herein, a hollow mesoporous carbon nanosheet anchored with sub‐10 nm SnO₂ nanoparticles (SnO₂@HMCNS) is synthesized as an anode host to addresses the above issues. The sodiophilic SnO₂ nanoseeds serve as nucleation sites to guide homogeneous Na deposition. Meanwhile, the open mesoporous channels not only promote the ion transport but also effectively stabilize the sodiophilic seeds and further reduce the nucleation overpotential, facilitating long‐term dendrite‐free Na deposition. Benefitting from these synergistic effects, the SnO₂@HMCNS electrode enables a durable cycling of ≈1800 h for a high area capacity of 2 mAh cm⁻² at 4 mA cm⁻², and a high average coulombic efficiency of 99.8%. Moreover, the SnO₂@HMCNS||NVP full cells delivers superior electrochemical performance. Especially, the anode‐free sodium metal batteries achieved ≈80% capacity retention after 200 cycles at 0.1 A g⁻¹. This work provides valuable insight into the interplay between sodiophilic seeds and porous skeletons, which is beneficial to constructing stable high‐efficiency SMAs.