Fully Reversible Conversion between SnO2 and Sn in SWNTs@SnO2@PPy Coaxial Nanocable As High Performance Anode Material for Lithium Ion Batteries

In this report, we designed a novel SWNTs@SnO2@PPy coaxial nanocable as superior anode material for the first time. The nanosized SnO2 particles (2-3 nm) were uniformly distributed between one dimension SWNTs core and PPy shell, as confirmed by XRD, SEM, and TEM characterizations. As an anode material for lithium ion batteries, this composite delivered a high capacity of 823 mAh g(-1) at 150 mA g(-1) after 100 cycles. Even at a high rate of 3000 mA g(-1), a reversible capacity of 480 mAh g(-1) still remained. Furthermore, the SnO2 in this composite exhibited a large capacity of 1486 mAh g(-1) as well as good capacity retention of 95% over 100 cycles. This result indicated the completely reversible reaction between Li4.4Sn and SnO2, greatly improving the theoretical capacity of SnO2 from 782 to 1493 mAh g(-1).