Construction of sheet–belt hybrid nanostructures from one-dimensional mesoporous TiO2(B) nanobelts and graphene sheets for advanced lithium-ion batteries

Abstract

TiO₂(B) is considered as a new kind of anode material, and an alternative to graphite, for high-power lithium ion batteries (LIBs) due to its characteristic pseudocapacitive energy storage mechanism. Herein, we firstly report the synthesis of one-dimensional (1D) mesoporous TiO₂(B) nanobelts by hydrothermal treatment of commercial TiO₂ (P25) powders in NaOH medium. The as-prepared TiO₂(B) nanobelts, with typical sizes of 50–100 nm in width and several micrometers in length, have mesopore channels in the range of 10–30 nm. Moreover, we demonstrate the use of graphene as an excellent mini-current collector to in situ construct unique hybrid sheet–belt nanostructures (G–TiO₂(B)) to optimize the performance. Such a 1D mesoporous TiO₂(B) structure can provide numerous open channels for the electrolyte to access and facilitate the ultrafast diffusion of lithium ions. In addition, the introduced graphene layers will both be favorable for the fast electron transport in the electrode and make a great contribution to the specific capacity. As a consequence, this G–TiO₂(B) hybrid can deliver an ultrahigh reversible capacity (over 430 mA h g⁻¹ at a low current density of 0.15 A g⁻¹), and present a superior rate capability (210 mA h g⁻¹ at 3 A g⁻¹).