Interfacial Bonding and Spatial Confined Architecture Enabling Dendrite‐Free Sodium/Potassium Metal Anodes

ABSTRACT Sodium metal batteries are garnering increasing attention due to their high theoretical capacity and the abundance of sodium resources. However, their practical application is impeded by uncontrolled dendrite growth and unstable solid electrolyte interphases. Herein, a robust interfacial engineering and confined architecture was fabricated via the electrostatic self‐assembly of SnO 2 quantum dots with graphene oxide, followed by a self‐propagating reduction reaction. The SnO 2 acts as highly active nucleation centers, guiding uniform Na nucleation, whereas 3D rGO frameworks provide an efficient electron‐transfer pathway, thereby facilitating effective regulation of Na deposition. Meanwhile, the formation of a strong interfacial Sn─O─C bond enhances electronic coupling and interfacial stability. Consequently, the SnO 2 ‐rGO‐2 electrode delivers outstanding long‐term cycling stability, operating stably for 9000 h at 2.0 mA cm −2 and 1.0 mAh cm −2 in symmetrical cells. The assembled Na@SnO 2 ‐rGO//Na 3 V 2 (PO 4 ) 3 full cells demonstrate remarkable rate and cyclic performance, with negligible capacity decay over 1000 cycles at 5 A g −1 . Moreover, the exceptional flexibility of Na@SnO 2 ‐rGO‐2 enables stable operation under various bending conditions, highlighting its potential for wearable applications. Notably, it can be extended to potassium metal systems and endows the full‐cell configuration with long‐term stability. This work establishes a generalizable design paradigm for next‐generation high‐energy alkali metal anodes.