Comparison between SnSb–C and Sn–C composites as anode materials for lithium-ion batteries

Abstract

SnSb–C and Sn–C composites have been fabricated by thermal annealing of the SnO₂–Sb₂O₃ and SnO₂ nanocomposite precursors under a C₂H₂-pyrolysis reducing atmosphere, respectively. Both of the as-formed SnSb intermetallic compounds and Sn particles are uniformly dispersed in the synchronously formed continuous amorphous carbon matrix. As the anode for lithium-ion batteries, the SnSb–C composite shows a high reversible capacity of 672.2 mA h g⁻¹ after 120 cycles at a current density of 100 mA g⁻¹ together with a rate performance of 468.8 mA h g⁻¹ at 500 mA g⁻¹, which are much better than those of the corresponding Sn–C composite (with similar carbon content to the SnSb–C composite; 432.1 mA h g⁻¹ after 120 cycles at 100 mA g⁻¹ and 331.9 mA h g⁻¹ at 500 mA g⁻¹). The better reversible capacity and cyclic performance of the SnSb–C composite can be attributed to the synergistic effect and strong affinity between electrochemical Sn and Sb phases as well as the synchronously formed continuous amorphous carbon matrix.