Electrochemical lithiation and de-lithiation of carbon nanotube-<f>Sn2</f>Sb nanocomposites

Nanocomposites of carbon nanotubes (CNTs) with <f>Sn2</f>Sb alloy nanoparticles were prepared by <f>KBH4</f> reduction of <f>SnCl2</f> and <f>SbCl3</f> 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 <f>Li+</f> storage compounds showed higher specific capacities than pristine CNTs and better cyclability than unsupported <f>Sn2</f>Sb particles. The first cycle de-lithiation capacity of 580 mAh/g from a CNT–56 wt%<f>Sn2</f>Sb nanocomposite was nevertheless reduced to 372 mAh/g after 80 deep charge and discharge cycles. The uniform dispersion of <f>Sn2</f>Sb alloy in the CNT web and on the surface of CNTs have substantially improved the usability of the <f>Sn2</f>Sb particles to the extent that the nanocomposites of CNTs and <f>Sn2</f>Sb may be considered as a candidate anode material for Li-ion batteries. [Copyright &y& Elsevier]