Fast sodium storage kinetics of lantern-like Ti_0.25Sn_0.75S₂ connected via carbon nanotubes

Tin disulfide is a promising anode material for sodium-ion batteries because of its advantages of abundant source materials and ultrahigh capacity. To solve the issues of its volume expansion and low conductivity, a moderate amount of elemental titanium was introduced into the crystal structure of SnS₂ to partially replace tin, providing lantern-like Ti_0.25Sn_0.75S₂, which was firmly linked with one-dimensional multi-walled carbon nanotubes (MWCNTs) to produce active materials for sodium-ion battery anodes. The electrochemically inert Ti-containing component provided a stable host structure during the insertion and extraction processes of sodium ions and enlarged the interlayer spacing of SnS₂. The combination of Ti_0.25Sn_0.75S₂ and MWCNTs gave a high-conductivity active material and prevented the dissolution of polysulfide. In particular, the lantern-like architecture with abundant pores and large surface area not only decreased the transmission path of sodium ions but also reserved a large space for volume expansion. Benefiting from these features, the Ti_0.25Sn_0.75S₂@MWCNTs composite exhibited an initial charging capacity of 426 mA h g⁻¹ and its capacity remained at 400 mA g⁻¹ after 1000 cycles. Furthermore, this anode material showed outstanding rate performance, displaying a capacity of 364 mA h g⁻¹ at a high current density of 800 mA g⁻¹.