Electrochemical properties of SnO2/carbon composite materials as anode material for lithium-ion batteries

SnO₂/carbon composite anode materials were synthesized from SnCl₄·5H₂O and sucrose via a hydrothermal route and a post heat-treatment. The synthesized spherical SnO₂/carbon powders show a cauliflower-like micro-sized structure. High annealing temperature results in partial reduction of SnO₂. Metallic Sn starts to emerge at 500 °C. High Sn content in SnO₂/carbon composite is favorable for the increase of initial coulombic efficiency but not for the cycling stability. The SnO₂/carbon annealed at 500 °C exhibits high specific capacity (∼400 mAh g⁻¹), stable cycling performance and good rate capability. The generation of Li₂O in the first lithiation process can prevent the aggregation of active Sn, while the carbon component can buffer the big volume change caused by lithiation/delithiation of active Sn. Both of them make contribution to the better cycle stability.