S-doped porous carbon confined SnS nanospheres with enhanced electrochemical performance for sodium-ion batteries

Abstract

Stannous based anode materials have been extensively studied for sodium ion batteries due to their high theoretical capacities. However, the large volume changes upon repeated cycling always cause their structural pulverization and capacity fading. Herein, we report the fabrication of S-doped porous hollow carbon confined SnS nanospheres particles and their good electrochemical performance as an anode material for sodium ion batteries. Unlike previous reports, stanniferous solid carbonaceous nanospheres are novelly prepared by a hydrothermal process, and they can be converted into yolk–shell structured Sn@C nanospheres after thermal annealing in a H₂/Ar atmosphere. The subsequent sulfidation process can produce S-doped carbon confined SnS hollow nanospheres with high porosity. The obtained SnS@SPC nanospheres possess a large Brunauer–Emmett–Teller (BET) surface area of 135.8 m² g⁻¹. As an anode material for sodium ion batteries, the obtained yolk–shell SnS@SPC exhibits a high reversible capacity of 512 mA h g⁻¹ at 100 mA g⁻¹ and good cycling stability. The void space between the carbon shell and the SnS yolk can accommodate the volume changes during the charge/discharge process. Meanwhile, the porous carbon shell can serve as a conductive skeleton and a reservoir for the electrolyte.