Anion-controlled synthesis of TiO2 nano-aggregates for Li ion battery electrodes

Abstract

Nano-sized anatase TiO2 was synthesized using surfactant-free hydrolysis method by controlling the ratio of anions in solution. The particle sizes of TiO2 were systematically tuned by the molar ratio of the Ti4+ precursors (chlorides and sulfates). Each TiO2 particle consists of an aggregation of 5 nm primary crystallites, resulting in a large specific surface area. TiO2 nano-aggregates (TiO2 NAs) which were 50 nm in size exhibited the best cycle stability. After calcination, the capacity of the TiO2 NA was enhanced to 171 mAh g(-1) at 100 cycles at a rate of 0.2 C due to the removal of impediments such as a hydroxyl group and physisorbed water, indicating that more than 0.5 Li was inserted into TiO2 at 100 cycles, and that these NAs had good rate capability at high current densities. (C) 2014 Published by Elsevier Inc.