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.

► SnO2/carbon powders with a cauliflower-like particle structure were synthesized. ► Post-annealing can improve the electrochemical properties of SnO2/C composite. ► The 500°C-annealed SnO2/C shows the best electrochemical performance. ► The lithium ion diffusion coefficients of the SnO2/C electrodes were calculated.