A Novel Green Approach to Synthesis of Nanostructured Li_4Ti_5O_(12) Anode Material

摘要

Li_4Ti_5O_(12)(LTO), which is strongly advocated as anode material for lithium ion batteries destined for land transport and grid-integration PV applications, was prepared via a novel low-temperature aqueous synthesis followed by annealing route using only inorganic compounds, including lithium hydroxide and inexpensive titanium tetrachloride as precursors. The synthesis of nanostructured LTO is done via the thermal transformation (annealing) of the aqueous synthesized intermediate phase, Li_(1.81)H_(0.19)Ti_2O_5·2H_2O (LTH). The nanostructure of the prepared LTO material was found to depend on the preceding intermediate phase formation conditions and applied annealing protocol. Thus nanoflower-structured LTO with "petals" 17-50 nm thick was produced by annealing the LTH intermediate phase at 400 °C. However, the morphology changed from flower structure into particulate, when annealing was done at a temperature higher than 500 °C. Finally, after annealing at 700 °C an LTO-rutile TiO_2 composite with average particle size of 100 nm was obtained. Possible mechanisms responsible for the different LTO nanocrystal morphologies are proposed.