Fluorine-doped nanocrystalline SnO₂ powders prepared via a single molecular precursor method as anode materials for Li-ion batteries

Fluorine-doped nanocrystalline tin dioxide materials (F:SnO₂) have been successfully prepared by the sol-gel process from a single molecular precursor followed by a thermal treatment at 450-650 °C. The resulting materials were characterized by FTIR spectroscopy, powder X-ray diffraction, nitrogen adsorption porosimetry (BET) and transmission electron microscopy (TEM). The mean particle size increased from 5 to 20 nm and the specific surface area decreased from 123 to 37 m²/g as the temperature of heat treatment was risen from 450 to 650 °C. Fluorine-doped nanocrystalline SnO₂ exhibited capacity of 560, 502, and 702 mA h/g with 48%, 50%, and 40% capacity retention after 25 cycles between 1.2 V and 50 mV at the rate of 25 mA/g, respectively. In comparison, commercial SnO₂ showed an initial capacity of 388 mA h/g, with only 23% capacity retention after 25 cycles.