Two-dimensional Sb@TiO2−x nanoplates as a high-performance anode material for sodium-ion batteries

Abstract

Alloy-based anode materials, including antimony (Sb), with high electronic conductivity and high capacity show great potential for sodium-ion batteries. However, the significant volume change of Sb leads to pulverization of active material and rapid capacity decay. Herein, two-dimensional (2D) Sb@TiO_2−x nanoplates, consisting of an amorphous TiO_2−x layer coated with ultra-small Sb nanocrystals, are prepared by a facile salt-template method. The incorporation of electrochemical/thermally-stable TiO_2−x is helpful to buffer the volume change of Sb and stabilize the SEI layer. In addition, the 2D structure of the Sb@TiO_2−x nanoplates can facilitate sodium ion diffusion and electronic transport during cycling. As a result, the 2D-Sb@TiO_2−x electrodes deliver a high reversible capacity of 568 mA h g⁻¹ at 100 mA g⁻¹, good rate capability (429 mA h g⁻¹ at 3200 mA g⁻¹) and stable cycling performance with a capacity retention of 95.2% after 100 cycles.