SiO2/TiO2 Composite Film for High Capacity and Excellent Cycling Stability in Lithium-Ion Battery Anodes

In this study, partially crystalline anodic TiO2 with SiO2 well-distributed througout the entire oxide film is prepared using plasma electrolytic oxidation (PEO) to obtain a high-capacity anode with an excellent cycling stability for Li-ion batteries. The micropore sizes in the anodic film become inhomogeneous as the SiO2 content is increased from 0% to 25%. The X-ray diffraction peaks show that the formed oxide contains the anatase and rutile phases of TiO2. In addition, X-ray photoelectron spectroscopy and energy-dispersive X-ray analyses confirm that TiO2 contains amorphous SiO2. Anodic oxides of the SiO2/TiO2 composite prepared by PEO in 0.2 M H2SO4 and 0.4 M Na2SiO3 electrolyte deliver the best performance in Li-ion batteries, exhibiting a capacity of 240 mu Ah cm(-2) at a fairly high current density of 500 mu A cm(-2). The composite film shows the typical Li-TiO2 and Li-SiO2 redox peaks in the cyclic voltammogram and a corresponding plateau in the galvanostatic charge/discharge curves. The as-prepared SiO2/TiO2 composite anode shows at least twice the capacity of other types of binder-free TiO2 and TiO2 composites and very stable cycling stability for more than 250 cycles despite the severe mechanical stress.