Ultralong 2H‐MoS₂ Nanowires from Topological Mo₂S₃ Phase Transformation toward Exceptional Sodium‐Ion Storage

1D transition metal dichalcogenide (TMD) nanowires (NWs) have attracted attention to act as energy storage and information technology materials, but the TMD NWs are unable to directly synthesized rather than hexagonal flakes due to the habit of in-planar isotropic crystal growth. Herein, the topological phase transformation is proposed to synthesize ultralong high-quality 2H-MoS₂ NWs from a surface-to-interior sulfurization of isomorphic Mo₂S₃ NWs. Mo₂S₃ endows a crystal structure with the [MoS] chains inserted into the 2H-MoS₂ crystal structure. The harvested MoS₂ NWs are average in length >150 µm and diameter ≈400 nm, and the electrical conductivity of ≈150 S m^-1 is much higher than the reported 2H-MoS₂ flakes (10^-2 S m^-1). As a sodium-ion battery (SIB) anode, 2H-MoS₂ NWs exhibit a high capacity of 705 mAh g^-1 at 0.2 A g^-1. The capacity retention of 85.6% is achieved after 9500 cycles at 5 A g^-1, superior to any reported TMD-based SIB anodes. Further in-situ structure characterizations reveal favorable reversible redox chemistry for 2H-MoS₂ NWs, and excellent cycling stability stems from the homogeneous surface stress release of the NWs during sodiation/desodiation. This work provides an effective strategy for preparing TMD NWs with excellent electrochemical performance.