High performance binder-free Sn coated carbon nanotube array anode

We report a binder-free Li-ion battery anode based on a tin (Sn) coated vertical-aligned carbon nanotube (VACNT) array. In this anode, the VACNT array, acting as a robust core matrix to support high theoretical capacity active material Sn, offers large inter-wire spacing for Sn expansion during the lithiation/de-lithiation processes and forms direct conductive pathways for electrons transporting. A remarkable enhancement in the capacity retentions abilities of this anode compared with pure Sn film anode has been achieved. A reversible capacity as high as 900 mAh g−1 over 400 cycles at 0.2 C and nearly 400 mAh g−1 over 1000 cycles at 0.5 C has been demonstrated respectively.