The nanocomposites of carbon nanotube with Sb and SnSb0.5 as Li-ion battery anodes

Nanocomposites of carbon nanotubes (CNTs) with Sb and SnSb0.5 particles were prepared by chemical reduction of SnCl2 and SbCl3 precursors in the presence of CNTs. SEM and TEM imaging showed that the Sb and SnSb0.5 particles are uniformly deposited on the CNT exterior and in the CNT web. These CNT-metal composites are active anode materials for lithium ion batteries, showing improved cyclability compared to unsupported Sb and Sn-Sb particles and higher reversible specific capacities than CNTs. The reversible capacities were as high as 462 mAh/g for CNT-36 wt.% Sb and 518 mAh/g for CNT-56 wt.% SnSb0.5. After 30 cycles, the capacity was 62.1% of the initial capacity for the former and 67.2% of the initial capacity for the later. In comparison Sb and SnSb0.5 could only retain 17.7 and 23.5%, respectively of their initial capacities in the same number of cycles. The improvement in cyclability may be attributed to the nanoscale dimension of the metal particles and CNTs' role as a buffer in relieving the mechanical stress induced by specific volume changes in electrochemical lithium insertion and extraction reactions. (C) 2002 Elsevier Science Ltd. All rights reserved.