In-situ synthesized carbon-coated Sn-SnO2 nanoparticles embedded in carbon nanotubes on Cu foam as anode material for lithium-ion batteries

Sn-based materials are considered as a prospective anode for lithium-ion batteries because of their high theoretical lithium storage capacity and large reserves. But the application of Sn-based materials is still hampered by their significant capacity decay owing to volume changes during lithiation and delithiation. To address this problem, we propose the in-situ synthesis of amorphous carbon-coated (thickness: -3 nm) Sn-SnO2 nanoparticles (size: -20-50 nm) embedded in helical carbon nanotubes (diameter: -30 nm) grown on Cu foam (C@Sn-SnO2/CNT) via hydrothermal and subsequent chemical vapor deposition process. The 3D hierarchical framework decorated by C@Sn-SnO2 nanoparticles provides enhanced contact between the electrode and electrolyte, and guarantees an efficient reversible conversion reaction. Moreover, the introduction of the carbon layer and carbon nanotubes inhibits large volume changes of Sn and SnO2 during cycling. In comparison with pure SnO2, C@Sn-SnO2/CNT displays superior lithium storage capability, rate performance, and cycle stability. The discharge capacity for C@Sn-SnO2/CNT at 0.2 A g-1 is 1772 mAh g-1 in the first cycle and 856 mAh g-1 after 300 cycles, as well as 480 mAh g-1 at 1 A g-1. Consequently, C@Sn-SnO2/CNT possesses enormous potentiality for practical application in high-performance lithium-ion batteries.