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

Abstract

Abstract In this study, partially crystalline anodic TiO 2 with SiO 2 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 SiO 2 content is increased from 0% to 25%. The X‐ray diffraction peaks show that the formed oxide contains the anatase and rutile phases of TiO 2 . In addition, X‐ray photoelectron spectroscopy and energy‐dispersive X‐ray analyses confirm that TiO 2 contains amorphous SiO 2 . Anodic oxides of the SiO 2 /TiO 2 composite prepared by PEO in 0.2 m H 2 SO 4 and 0.4 m Na 2 SiO 3 electrolyte deliver the best performance in Li‐ion batteries, exhibiting a capacity of 240 µAh cm −2 at a fairly high current density of 500 µA cm –2 . The composite film shows the typical Li–TiO 2 and Li–SiO 2 redox peaks in the cyclic voltammogram and a corresponding plateau in the galvanostatic charge/discharge curves. The as‐prepared SiO 2 /TiO 2 composite anode shows at least twice the capacity of other types of binder‐free TiO 2 and TiO 2 composites and very stable cycling stability for more than 250 cycles despite the severe mechanical stress.