Electrochemical lithiation and de-lithiation of carbon nanotube-Sn 2Sb nanocomposites

Abstract

Nanocomposites of carbon nanotubes (CNTs) with Sn 2Sb alloy nanoparticles were prepared by KBH 4 reduction of SnCl 2 and SbCl 3 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 Sn 2Sb particles. The first cycle de-lithiation capacity of 580 mAh/g from a CNT–56 wt%Sn 2Sb nanocomposite was nevertheless reduced to 372 mAh/g after 80 deep charge and discharge cycles. The uniform dispersion of Sn 2Sb alloy in the CNT web and on the surface of CNTs have substantially improved the usability of the Sn 2Sb particles to the extent that the nanocomposites of CNTs and Sn 2Sb may be considered as a candidate anode material for Li-ion batteries.