A Series of Molecule-Intercalated MoS₂ as Anode Materials for Sodium Ion Batteries

Molybdenum disulfide (MoS₂) with a graphite-like layer structure has attracted substantial interest as an anode material for sodium ion batteries (SIBs), but its inherent poor electrical conductivity and slow sodium ion transportation are the two important factors that limit its use in SIBs. Here, we report a general approach to synthesize a series of molecule-intercalated MoS₂ with a precisely controlled interlayer distance of 0.62 to 1.24 nm in which the electrical conductivity could be also widely and finely adjusted from 1.3 × 10^-4 to 3.5 × 10^-2 S cm^-1 via the insertion of different molecules. By adjusting the interlayer space and enhancing the electrical conductivity, the highest initial sodium ion storage capacity of 465 mA h g^-1 (vs 195 mA h g^-1 for the pure MoS₂ anode) and the highest capacity of 420 mA h g^-1 (vs 31 mA h g^-1 for the pure MoS₂ anode) after 600 cycles at a rate of 100 mA g^-1 were obtained. The excellent performance is credited to the rapid Na⁺ and electron transport and higher material utilization derived from the synergistic effect of the expanded interlayer space and the higher electronic conductivity. The results provide some inspiration for the design and construction of superior layered anode materials for sodium-ion batteries.