New facile synthesis of TiO2 hollow sphere with an opening hole and its enhanced rate performance in lithium-ion batteries

With the aid of the slow release of water from esterification reactions, a simple one-step solvothermal method was developed to prepare TiO2 hollow spheres with an opening hole. Organic carboxylic acids (CA) were exploited as not only the reactant to conduct esterification with ethanol, but also the coordination agent to modify titanium n-butoxide (TNB) to manipulate its hydroxylation and condensation process. The specific TiO2 morphologies prepared by this CA-assisted method significantly depend on the molecular structure and relative concentration of the carboxylic acids used. Appropriate carbon chain length of the CA molecule and the optimal molar ratio of CA/TNB are the essential factors to fabricate well-developed TiO2 hollow spheres with an opening hole. The surface hole facilitates active material transportation into the hollow interior, so this structure of TiO2 has been utilized in lithium-ion batteries and exhibits superiority in rate performance compared to closed spheres.