Interwoven scaffolded porous titanium oxide nanocubes/carbon nanotubes framework for high-performance sodium-ion battery

Abstract

Porous titanium oxide (TiO 2 ) nanocubes combining with carbon nanotubes (CNTs) framework greatly improve the utilization efficiency and enhance their sodium storage. • An interwoven scaffolded TiO 2 /CNTs framework is designed and constructed for sodium storage. • The TiO 2 /CNTs framework provides abundant channels and shorter diffusion pathways for electrons and ions. • The TiO 2 /CNTs framework demonstrates low strain and superior transport kinetics in Na + intercalation/extraction processes. • The TiO 2 /CNTs framework provides fast channels for Na + insertion/extraction with a much lower energy barrier. Supercapacitor-like Na-ion batteries have attracted much attention due to the high energy density of batteries and power density of capacitors. Titanium dioxide (TiO 2 ), is a promising anode material. Its performance is however seriously hindered by its low electrical conductivity and the sluggish diffusion of sodium ions (Na + ) in the TiO 2 matrix. Herein, this work combines porous TiO 2 nanocubes with carbon nanotubes (CNTs) to enhance the electrical conductivity and accelerate Na + diffusivity for Na-ion batteries (NIBs). In this composite, an interwoven scaffolded TiO 2 /CNTs framework is formed to provide abundant channels and shorter diffusion pathways for electrons and ions. The in-situ X-ray diffraction and cyclic voltammetry confirm the low strain and superior transport kinetics in Na + intercalation/extraction processes. In addition, the chemically bonded TiO 2 /CNTs hybrid provides a more feasible channel for Na + insertion/extraction with a much lower energy barrier. Consequently, the TiO 2 /CNTs composite exhibits excellent electrochemical performance with a capacity of 223.4 mAh g −1 at 1 C and a capacity of 142.8 mAh g −1 at 10 C (3.35 A g −1 ). The work here reveals that the combination of active materials with CNTs can largely improve the utilization efficiency and enhance their sodium storage.