Nanocrystalline Ti_2/3Sn_1/3O_2 as anode material for Li-ion batteries

摘要

We prepared nanocrystalline Ti_(2/3)Sn_(1/3)O_2 by a coprecipitation method starting from Ti(isopropoxide)4 and SnCl_4-5H_2O followed by calcination at 600 C. TEM and XRD measurements reveal crystallite sizes of about 5 nm and a crystal structure equivalent to those of TiO_2 rutile and SnO_2 cassiterite. The local structure was investigated with ~119Sn NMR and Sn Mossbauer spectroscopy. The material was cycled with C/20 at voltages between 3.0 and 0.02 V against Li metal. Specific capacities of 300mAhg~(-1) were obtained for 100 cycles with voltage profiles very similar to those of pure SnO_2. Faster cycling leads to strong decrease of the capacities but after returning to C/20 the initial values are obtained.