Nano-SnO ₂ /Carbon Nanotube Hairball Composite as a High-Capacity Anode Material for Lithium Ion Batteries

An ultrafine (6-7 nm) and well dispersed nano-SnO ₂ /carbon nanotube hairball (SnO ₂ /CNTH) composite material with a three-dimensional (3D) hierarchical structure is prepared by spray drying and solvothermal method. This composite material demonstrates much superior electrochemical performance over the bare SnO ₂ and an obviously improved Li-storage performance over the SnO ₂ /CNT composite in respect to specific capacity, rate performance, and cycling stability. It exhibits a high reversible capacity of 1109.5 mAh g ^-1 at 0.1 A g ^-1 , achieves a maximum reversible capacity of 1090.6 mAh g ^-1 when continuously cycled at 0.2 A g ^-1 , and remains at a capacity of 809.2 mAh g ^-1 after 100 cycles with the capacity retention of 74.2%. The improved electrochemical performance is attributed to the increased conductivity and hence the enhanced electrode reactivity as well as the electrode stability due to the particular 3D hierarchical structure of the SnO ₂ /CNTH composite. This structure can also address the large volume change upon cycling.