Ultrathin\nTiO₂(B) Nanorods with Superior Lithium-Ion Storage Performance

Abstract

The peculiar architecture of a novel\nclass of anisotropic TiO₂(B) nanocrystals, which were synthesized\nby an surfactant-assisted nonaqueous sol–gel route, was profitably\nexploited to fabricate highly efficient mesoporous electrodes for\nLi storage. These electrodes are composed of a continuous spongy network\nof interconnected nanoscale units with a rod-shaped profile that terminates\ninto one or two bulgelike or branch-shaped apexes spanning areas of\nabout 5 × 10 nm². This architecture transcribes into\na superior cycling performance (a charge capacitance of 222 mAh g^–1 was achieved by a carbon-free TiO₂(B)-nanorods-based\nelectrode vs 110 mAh g^–1 exhibited by a comparable\nTiO₂-anatase electrode) and good chemical stability (more\nthan 90% of the initial capacity remains after 100 charging/discharging\ncycles). Their outstanding lithiation/delithiation capabilities were\nalso exploited to fabricate electrochromic devices that revealed\nan excellent coloration efficiency (130 cm² C^–1 at 800 nm) upon the application of 1.5 V as well as an extremely\nfast electrochromic switching (coloration time ∼5 s).