Oxygen‐Doped Carbon Monolayer Intercalation and Selenization Stabilizing 1T‐Rich MoS ₂ to Enable Fast and Durable Sodium‐Ion Storage

Abstract Metallic 1T‐MoS ₂ is a promising anode for sodium‐ion batteries (SIBs) due to its excellent conductivity, abundant active sites, and low adsorption barrier for Na ⁺ . Unfortunately, intrinsic metastable features and defect‐caused poor structure stability pose an unparalleled challenge in cycle life. Herein, a synergetic strategy of carbon intercalation and selenization is proposed to construct stable 1T‐rich MoS _2‐x Se _y , which is covalently bonded to intercalated carbon monolayers via C─S/Se and C─O─Mo bonds on reduced graphene oxide (MoS _2‐x Se _y /m‐C@rGO). The heterostructure expands the interlayer distance for fast Na ⁺ diffusion, provides confined atomic‐thickness spacing stabilizing the layered structure, induces the formation of the 1T phase, and promotes charge transfer from carbon monolayers to S atoms. Selenization remediates sulfur vacancies while enabling the stabilization of the 1T phase due to induced lattice strains and electronic structure modulation. Consequently, the electrode delivers a capacity of 242.3 mAh g ⁻¹ after 2500 cycles at 5 A g ⁻¹ , corresponding to a capacity retention of 82.6% relative to the initial capacity at 5 A g ⁻¹ . The full cell delivers an appealing energy output of 167.7 Wh kg ⁻¹ at 183 W kg ⁻¹ . An atomic‐level mechanism of reversible reconstruction is proposed. This work provides valuable insights toward the design of durable, high‐rate electrodes in SIBs.