Synergistic Montmorillonite Channels and Heteroatom‐Doped Carbon Networks Enabling Fast Ion Transport and Uniform Deposition for Stable Sodium Metal Anodes

Abstract The sodium metal batteries (SMBs), characterized by their high theoretical capacity and cost‐effectiveness, are regarded as a promising candidate for the development of high‐energy‐density metal batteries. However, challenges such as dendrite formation and unstable solid electrolyte interphase (SEI) hinder cycling stability and safety. Herein, a heterogeneous composite material, C‐MMT, is constructed by integrating acid‐etched montmorillonite (MMT) with nitrogen/sulfur co‐doped carbon. This design leverages the rigid, layered framework of inorganic MMT to provide low‐impedance diffusion pathways for rapid sodium‐ion transport, while the elastic nitrogen/sulfur‐doped carbon provides sodiophilic nucleation sites, thereby promoting a uniform interfacial electric field distribution and buffering volume changes. As a result, the symmetric C‐MMT@Na cell exhibits an exceptional cycling lifespan exceeding 3000 h and significantly enhances the rate performance and capacity retention of Na ₃ V ₂ (PO ₄ ) ₃ cathodes, maintaining 83.7% of the initial capacity after 2000 cycles at 5 C. This study combines rational material design with computational simulations to propose an effective strategy that exploits the synergistic effects between layered MMT and doped carbon, offering new insights into the stabilization of sodium metal anodes.