Ultrahigh initial coulombic efficiency for deep sodium storage enabled by carbon-free vanadium-doping MoS₂...

Molybdenum disulfide (MoS₂) has garnered attention as a promising anode material for sodium-ion batteries due to its high theoretical capacity and unique lamellar texture. Nevertheless, unmodified MoS₂ suffers from inferior electrical conductivity, poor reaction reversibility, and suboptimal cycle life upon repeated sodiation/desodiation. In this study, a novel carbon-free V-heteroatom doping MoS₂ composite (abbr. VMS) with hierarchical laurustinus-like structure was synthesized by a facile one-step hydrothermal process. Specifically, the rational doping of V-atoms can effectively modulate the intrinsic electronic structure of pure MoS₂, resulting in enhanced Na-ion diffusion rate, improved reaction kinetics and reduced activation energy compared to bare MoS₂. Additionally, the hierarchical structure of the VMS composite, with sufficient spacing, effectively mitigates mechanical stress and ensures the integrity of active materials. Consequently, the prepared VMS composite possesses exceptional reaction reversibility (average ICE value of 92 %) and remarkable capacity retention (92.1 % after 450 cycles at 10 A/g). These findings contribute valuable insights into the development of advanced MoS₂-based anode for sodium ion batteries.