Ultrathin TiO₂(B) Nanorods with Superior Lithium-Ion Storage Performance

Abstract

The peculiar architecture of a novel class of anisotropic TiO₂(B) nanocrystals, which were synthesized by an surfactant-assisted nonaqueous sol–gel route, was profitably exploited to fabricate highly efficient mesoporous electrodes for Li storage. These electrodes are composed of a continuous spongy network of interconnected nanoscale units with a rod-shaped profile that terminates into one or two bulgelike or branch-shaped apexes spanning areas of about 5 × 10 nm². This architecture transcribes into a superior cycling performance (a charge capacitance of 222 mAh g^–1 was achieved by a carbon-free TiO₂(B)-nanorods-based electrode vs 110 mAh g^–1 exhibited by a comparable TiO₂-anatase electrode) and good chemical stability (more than 90% of the initial capacity remains after 100 charging/discharging cycles). Their outstanding lithiation/delithiation capabilities were also exploited to fabricate electrochromic devices that revealed an excellent coloration efficiency (130 cm² C^–1 at 800 nm) upon the application of 1.5 V as well as an extremely fast electrochromic switching (coloration time ∼5 s)