Electrochemical performance of mixed crystallographic phase nanotubes and nanosheets of titania and titania–carbon/silver composites for lithium-ion batteries

Abstract

The role of homogeneity in ex situ grown conductive coatings and dimensionality in the lithium storage properties of TiO₂ is discussed here. TiO₂ nanotube and nanosheet comprising of mixed crystallographic phases of anatase and TiO₂ (B) have been synthesized by an optimized hydrothermal method. Surface modifications of TiO₂ nanotube are realized via coating the nanotube with Ag nanoparticles and amorphous carbon. The first discharge cycle capacity (at current rate = 10 mA g⁻¹) for TiO₂ nanotube and nanosheet were 355 mAh g⁻¹ and 225 mAh g⁻¹, respectively. The conductive surface coating stabilized the titania crystallographic structure during lithium insertion–deinsertion processes via reduction in the accessibility of lithium ions to the trapping sites. The irreversible capacity is beneficially minimized from 110 mAh g⁻¹ for TiO₂ nanotubes to 96 mAh g⁻¹ and 57 mAh g⁻¹ respectively for Ag and carbon modified TiO₂ nanotubes. The homogeneously coated amorphous carbon over TiO₂ renders better lithium battery performance than randomly distributed Ag nanoparticles coated TiO₂ due to efficient hopping of electrons.