Nanostructures and lithium electrochemical reactivity of lithium titanites and titanium oxides: A review

Being inherently safe and chemically compatible with the electrolyte, titanium oxide-based materials, including both Li-titanites and various TiO₂ polymorphs, are considered alternatives to carbonaceous anodes in Li-ion batteries. Given the commercial success of the spinel lithium titanites, TiO₂ polymorphs, in particular in nanostructured forms, have been fabricated and investigated for the applications. Nanostructuring leads to increased reaction areas, shortened Li⁺ diffusion and potentially enhanced solubility/capacity. Integration with an electron-conductive second phase into the TiO₂-based nanostructures eases the electron transport, resulting in further improved lithium electrochemical activity and the overall electrochemical performance. This paper reviews structural characteristics and Li-electrochemical reactivity, along with synthetic approaches, of nanostructures and nano-composites based on lithium titanites and TiO₂ polymorphs that include rutile, anatase, bronze and brookite.