Multifunctional TiO2 coating for a SiO anode in Li-ion batteries

A titanium dioxide (TiO2) surface coating was applied to improve both the electrochemical and thermal properties of SiO as a high energy density anode for Li-ion batteries. A nano-scale, thin anatase TiO2 coating was achieved using a facile sol-gel process, and coated and non-coated SiO were characterized using various analytical methods. Increased initial Coulombic efficiency and reversible capacity were observed in the TiO2-coated SiO, which resulted in a 30% increase in the volumetric energy density as compared to that of bare SiO. Furthermore, the TiO2 coating remarkably suppressed the high-rate exothermic reactions observed in lithiated bare SiO and carbon-coated SiO, which could retard thermal runaway and the safety problems that it produces. Hence, an interfacial layer of TiO2 could be an alternative or supplementary coating material to carbon for safety-guaranteed and higher energy density Si-based Li-ion batteries.