The Effect of Thermal Treatment on the Morphology and Structure of SnO 2 /TiO 2 Composite Micro-fibers

Tin oxide and titanium oxide (SnO 2 /TiO 2 ) composite fibers were prepared from polyvinylpyrrolidone (PVP)/SnO 2 /TiO 2 precursor solutions with different SnO 2 to TiO 2 ratios of 1:1, 2:1, 3:1, and 3:2. The precursor fibers were thermally treated using different heating rates to prepare SnO 2 /TiO 2 fibers with micro-belt morphology. The characterization of the SnO 2 /TiO 2 composite fibers was performed using a scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and thermogravimetric analysis (TGA). The SEM images showed that the fibers were flat and had micron-sized diameters. EDS mapping of the precursor fibers showed the fibers to have a distribution of Sn and Ti throughout the surface with areas of high concentration of carbon, nitrogen, and oxygen. The XRD, XPS, and Raman data confirmed the presence of SnO 2 /TiO 2 . Initial electrochemical testing of Li-ion half cells, using SnO 2 /TiO 2 as anode material, showed the composite fibers with different ratios to have higher specific capacity and slower anode pulverization than SnO 2 . The results reported in this work showed that SnO 2 /TiO 2 composite fibers with micro-belt morphology could be achieved, and the synthesis was susceptible to both the temperature ramp rate during calcination of the precursor fibers and the SnO 2 to TiO 2 ratio in the composite fibers.