Facile and Rapid Synthesis of Highly Porous Wirelike TiO2 as Anodes for Lithium-Ion Batteries

Highly porous wirelike TiO2 nanostructures have been synthesized by a simple two-step process. The morphological and structural characterizations reveal that the TiO2 wires typically have diameters from 0.4 to 2 mu m, and lengths from 2 to 20 mu m. The TiO2 wires are highly porous and comprise of interconnected nanocrystals with diameters of 8 +/- 2 nm resulting in a high specific surface area of 252 m(2) g(-1). The effects of experimental parameters on the structure and morphology of the porous wirelike TiO2 have been investigated and the possible formation processes of these porous nanostructures are discussed. Galvanostatic charge/discharge tests indicate that the porous wirelike TiO2 samples exhibit stable reversible lithium ion storage capacities of 167.1 +/- 0.7, 152.1 +/- 0.8, 139.7 +/- 0.3, and 116.1 +/- 1.1 mA h g(-1) at 0.5, 1, 2, and 5 C rates, respectively. Such improved performance could be ascribed to their unique porous and ID nanostructures facilitating better electrolyte penetration, higher diffusion rate of electrons and lithium ion, and variation of accommodated volumes during the charge/discharge cycles.