Electrochemical Properties of Spherical Hollow SnO₂-TiO₂-C Composite Powders Prepared by Spray Pyrolysis

摘要

Hollow spherical SnO2-TiO2-C composite powders with uniform compositions are prepared by spraypyrolysis from precursor solutions containing Sn and Ti compounds along with citric acid and ethyleneglycol. The prepared composite powders are subsequently heat-treated at various temperatures.Samples treated at 400 C show the presence of amorphous structures and fine crystallites with sizesranging to a few nanometers. Crystalline peaks corresponding to rutile-like crystal structures areobserved in the XRD patterns of the composite powders treated at 600 C. The peaks in the XRDpatterns of the SnO2 phase with the rutile structure marginally shift to higher angles because of theformation of the SnO2-TiO2 solid solution. Crystals with sizes below 10 nm present in compositepowders treated at 600 C are coated with a layer of amorphous carbon. Phase separation of Sn and Ticomponents dose not occur during the crystallization of the composite powders by heat-treatment. Thecycle performances of the SnO2-TiO2-C composite powders are better than that of pure SnO2 powders-1 at a constant charge and discharge rate of 700 mA g in the voltage range 0.01.0 V. The dischargecapacities after 50 cycles for the composite powders treated at 600 C are 394, 396, 327, and 244 mAh-1 -1 g at discharge rates of 300, 1400, 2100, and 3500 mA g , respectively.