Rational Design and Controllable Synthesis of Multishelled Fe2O3@SnO2@C Nanotubes as Advanced Anode Material for Lithium-/Sodium-Ion Batteries.

Hierarchical Fe2O3 and SnO2 nanostructures have shown great potential for applications in high-performance ion batteries because of their superiority, including wide resources, facile preparation, environmental friendliness, and high energy density. However, some severe challenges, such as rapid capacity decay due to volume expansion upon cycling and poor conductivity, limit their rate performance. To address this issue, multishelled Fe2O3@SnO2@C (FSC) nanotubes were designed and synthesized by using a template method and Ostwald interaction. The as-prepared FSC nanotubes can deliver a high capacity of 1659 mA h g-1 at a current density of 200 mA g-1 and a high reversible capacity of 818 mA h g-1 at 2000 mA g-1 for lithium-ion batteries. Particularly, a high specific capacity of 1024 mA h g-1 is still maintained after 100 charging/discharging cycles at 200 mA g-1. Applied in sodium-ion batteries, the multishelled FSC nanotubes manifest a high specific capacity of 449 mA h g-1 after 180 cycles at 50 mA g-1. Such excellent performances of the as-fabricated FSC nanotubes may be due to the unique multishelled tubular structure, porous characteristics, and high specific surface area. Therefore, the present work provides an outstanding method to improve the energy storage performance of metal oxide composites and other types of nanocomposites.