Molecular Design Strategy for Ordered Mesoporous Stoichiometric Metal Oxide

Abstract

A molecular design strategy is used to construct ordered mesoporous Ti³⁺ -doped Li₄ Ti₅ O₁₂ nanocrystal frameworks (OM-Ti³⁺ -Li₄ Ti₅ O₁₂ ) by the stoichiometric cationic coordination assembly process. Ti⁴⁺ /Li⁺ -citrate chelate is designed as a new molecular precursor, in which the citrate can not only stoichiometrically coordinate Ti⁴⁺ with Li⁺ homogeneously at the atomic scale, but also interact strongly with the PEO segments in the Pluronic F127. These features make the co-assembly and crystallization process more controllable, thus benefiting for the formation of the ordered mesostructures. The resultant OM-Ti³⁺ -Li₄ Ti₅ O₁₂ shows excellent rate (143 mAh g^-1 at 30 C) and cycling performances (<0.005 % fading per cycle). This work could open a facile avenue to constructing stoichiometric ordered mesoporous oxides or minerals with highly crystalline frameworks.

Keywords: Li4Ti5O12; co-assembly; lithium ion batteries; mesoporous materials.