Electrochemical lithiation and de-lithiation of carbon nanotube-Sn2Sb nanocomposites

Nanocomposites of carbon nanotubes (CNTs) with Sn2Sb alloy nanoparticles were prepared by KBH4 reduction of SnCl2 and SbCl3 precursors in the presence of CNTs. SEM and TEM examinations showed that most of the Sn-Sb alloy nanoparticles were present in high dispersion in the CNT web, while others were deposited directly on the outside surface of the carbon nanotubes. Constant current charge and discharge tests using the nanocomposites as Li+ storage compounds showed higher specific capacities than pristine CNTs and better cyclability than unsupported Sn2Sb particles. The first cycle de-lithiation capacity of 580 mAh/g from a CNT-56 wt%Sn2Sb nanocomposite was nevertheless reduced to 372 mAh/g after 80 deep charge and discharge cycles. The uniform dispersion of Sn2Sb alloy in the CNT web and on the surface of CNTs have substantially improved the usability of the Sn2Sb particles to the extent that the nanocomposites of CNTs and Sn2Sb may be considered as a candidate anode material for Li-ion batteries. (C) 2002 Published by Elsevier Science B.V.