Three-dimensional hierarchical Li₄Ti₅O₁₂ nanoarchitecture by a simple hydrothermal method

The spinel Li₄Ti₅O₁₂ (LTO) is a promising candidate as a superior electrode material for energy storage devices due to the extremely small volume expansion/contraction during the charge/discharge processes of a battery. There are various synthetic approaches for the nanostructured LTO electrode: sol-gel, sonochemical, solution-combustion, hydrothermal methods, and others. Herein, three-dimensional (3D) high-density heterogeneous LTO architectures are fabricated by employing the TiO₂ nanorods (NRs) branched SnO₂ nanowire (NW) arrays as the template. The TiO₂ NRs were effectively converted by the hydrothermal method into the LTO NRs that have a width of 40-nm and length of 100-nm, which induce branch/backbone structured LTO-SnO₂ composites. Interestingly, the 3D LTO architectures exhibit unique geometrical shapes because the NRs are surrounded by small nanoparticles. We also discuss how the temperature and solvent affect the LTO nanostructure formation in detail. These results suggest that using a template can provide a new method for designing and synthesizing various classes of 3D architecturing synthesis.