Facile hydrothermal synthesis of SnO2/C microspheres and double layered core–shell SnO2 microspheres as anode materials for Li-ion secondary batteries

Abstract

SnO₂/C microspheres and double layered core–shell SnO₂ microspheres have been synthesized by a facile hydrothermal method with a post heat-treatment. The soluble starch used as carbon source and the mass ratio of starch to SnCl₄·5H₂O play key roles in the formation of SnO₂/C microspheres, and the hydrothermal synthesis mechanism of SnO₂/C microspheres has been proposed. SnO₂/C-1.0 microspheres (the mass ratio of soluble starch to SnCl₄·5H₂O is 1 : 1) with good spherical shape and 34.91 wt% of SnO₂ exhibit superior rate capability and cyclic stability, while double layered core–shell SnO₂ microspheres show improved electrochemical performance compared to SnO₂ particles. The electrode based on SnO₂/C-1.0 microspheres delivers a reversible discharge capacity of 568 mA h g⁻¹ at a constant current density of 100 mA g⁻¹ in the second cycle, and 379 mA h g⁻¹ (67% retention) is retained after the 50th cycle, suggesting SnO₂/C microspheres are promising candidates for energy storage.