TiNb2O7/RGO composites as anode materials for high-performance lithium-ion batteries

Abstract

TiNb₂O₇ is regarded as an auspicious anode material for next generation lithium-ion batteries because of its high theoretical specific capacity (387 mAh/g) and operating potential (1.6 V vs. Li⁺/Li). However, the inherent problems of TiNb₂O₇ are poor rate capability and low intrinsic conductivity. Herein, a simple solvothermal and subsequent calcination method is proposed to prepare the composite of TiNb₂O₇ porous microspheres with reduced graphene oxide (RGO). The porous microsphere structure significantly reduces the Li⁺ transport resistance of the material. Due to the introduction of graphene, the electrochemical impedance of the composite is much reduced, which greatly increases the electronic/ionic conductivity. TNO/RGO₆ has long cycling stability and higher conductivity. A reversible discharge-specific capacity of 248.8 mAh/g was retained after 500 cycles at a current density of 2 C and a reversible capacity of 152.7 mAh/g at 5 C.