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

Abstract

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.