High-Capacity C/Sn-Composites as Next-Generation Anodes for Sodium-Ion Batteries

This work investigates carbon/tin composites as anode materials for high-performance sodium-ion batteries (SIBs). The material is prepared by dispersing SnO2 nanopowder in fructose solution, followed by thermal treatment under inert gas, leading to fructose carbonization and carbothermal reduction of SnO2 forming metallic Sn, confirmed by thermogravimetric analysis (TGA) and X-ray diffraction (XRD). Different thermal procedures, including a single-step with extended holding times and a two-step process, are explored; the latter separates fructose carbonization from carbothermal reduction, with the second step conducted under conventional heating conditions or via an ultrafast heating method. The composite with low carbon content exhibits a sodiation capacity of 749.2 mAh g–1 in the first cycle with a high initial cycle efficiency (ICE) of 83.2%. After 100 cycles at 37.2 mA g–1, it retains a capacity of 351 mAh g–1. The material demonstrates excellent rate capability, maintaining a capacity of 344.5 mAh g–1 at a rate of 2380 mA g–1.