Facile synthesis and in situ transmission electron microscopy investigation of a highly stable Sb2Te3/C nanocomposite for sodium-ion batteries

Sb-based anode materials attract a great deal of attention recently due to their high capacity. However, large volume change during sodiation and desodiation leads to poor cyclic performance. Introduction of inactive element would improve the cyclic performance but reduce the capacity significantly. In this work, Na-active Te was introduced and Sb2Te3/C nanocomposite has been successfully prepared by a high energy ball mill method. The Sb2Te3 nanocrystals with a size of about 20 nm embedded in the carbon matrix are produced. The as-obtained Sb2Te3/C exhibits specific capacity of 360 mA h g-1 with capacity retention of 93% after 400 cycles at 1 A g-1. In situ transmission electron microscopy study was carried out to investigate the origin of the high capacity retention. The synergetic effects of carbon matrix and nanosized particles can release stress efficiently during large volume change and suppress the aggregation of the pulverized nanoparticles.