Triple-walled SnO2@N-doped carbon@SnO2 nanotubes as an advanced anode material for lithium and sodium storage

Abstract

Triple-walled SnO₂@N-doped carbon@SnO₂ nanotubes are synthesized by a facile process with high-quality PPy nanotubes as the template. This structure has SnO₂ nanoparticles closely attached to both the external and internal surfaces of N-doped carbon nanotubes, thus assuring good charge-transfer kinetics to all the SnO₂ nanoparticles. Meanwhile, it doubles the loading density of SnO₂ in the nanocomposite, and offers adequate room to accommodate the volume deformation of SnO₂ on/in the nanotubes. All these features make the nanocomposite well fitted for lithium or sodium storage. It is found that this nanocomposite as an anode material for lithium ion batteries can deliver a reversible capacity of 935 mA h g⁻¹ after 100 cycles at 200 mA g⁻¹, or 658 mA h g⁻¹ after 300 cycles at 2000 mA g⁻¹. In the case of sodium ion batteries, its capacity could be still preserved at 492 mA h g⁻¹ after 50 cycles at a current density of 25 mA g⁻¹.