Hydrothermal Growth and Electrochemical Performance of Carbon-Coated Porous SnO₂ Nanospheres

The porous SnO₂ nanospheres were fabricated by hydrothermal method and then the carbon layer was coated as a buffer cushion through a facile hydrothermal process in aqueous D-glucose followed by a subsequent calcination at 500 °C in a nitrogen (N₂) atmosphere. The materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and Raman spectra. Based on the experimental results, the thickness of carbon layer could be well-controlled by hydrothermal time and D-glucose concentration. The typical as-prepared carbon-coated porous SnO₂ nanospheres show an initial discharge capacity of 711.26 mAhg^–1 and a stabilized capacity at 414 mAhg^–1 after 50 cycles. It was shown that the carbon-coated porous SnO₂ nanospheres exhibited better electrochemical properties in terms of high Columbic efficiency and rate performance, which are attributed to the porous structure and the outer carbon layer.