TiO₂(B) nanowire arrays on Ti foil substrate as three-dimensional anode for lithium-ion batteries

Highlights: • TiO₂(B) nanowire arrays (TBNA) were synthesized directly on Ti foil substrate by a simple hydrothermal routine as a three-dimensional (3D) anode for lithium ion batteries. • TBNA is composed of numerous uniform TiO₂(B) nanowires, which are distributed regularly on the Ti foil surface forming an unique 3D structure. • The high electrochemical performance is ascribed to the unique 3D structure, which provides good electronic conductivity and accessible lithium ion paths, as well as a large surface area. - Abstract: TiO₂(B) nanowire arrays (TBNA) were synthesized directly on Ti foil substrate as a three-dimensional (3D) anode for lithium ion batteries. The crystal phase of TiO₂(B) in the products was confirmed by X-ray diffraction and Raman spectroscopy. Observations from electron microscopy revealed uniform nanowires that were distributed regularly on the surface of the Ti metal foil forming an unique 3D nanowire array structure. TBNA exhibits promising electrochemical performance, the discharge capacity is extremely high even over the theoretical capacity of TiO₂(B) at C/20, though it decays gradually, it is still high as 124.9 mAh/g at 2C. The dramatic improvement in reversible capacity is ascribed to the unique structure of 3D nanowire array, which provides good electronic conductivity and accessible lithium ion paths, as well as a large surface area.