Robust S-doped TiO2@N,S-codoped carbon nanotube arrays as free-binder anodes for efficient sodium storage

Titanium dioxide (TiO2) has been investigated broadly as a stable, safe, and cheap anode material for sodium-ion batteries in recent years. However, the poor electronic conductivity and inherent sluggish sodium ion diffusion hinder its practical applications. Herein, a self-template and in situ vulcanization strategy is developed to synthesize self-supported hybrid nanotube arrays composed of nitrogen/sulfur-codoped carbon coated sulfur-doped TiO2 nanotubes (S-TiO2@NS-C) starting from H2Ti2O5 center dot H2O nanoarrays. The S-TiO2@NS-C composite with one-dimensional nano-sized subunits integrates several merits. Specifically, sulfur doping strongly improves the Na+ storage ability of TiO2@C-N nanotubes by narrowing the bandgap of original TiO2. Originating from the nanoarrays structures built from hollow nanotubes, carbon layer and sulfur doping, the sluggish Na+ insertion/extraction kinetics is effectively improved and the volume variation of the electrode material is significantly alleviated. As a result, the S-TiO2@NS-C nanoarrays present efficient sodium storage properties. The greatly improved sodium storage performances of S-TiO2@NS-C nanoarrays confirm the importance of rational engineering and synthesis of hollow array architectures with higher complexity. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

A self-template and in situ vulcanization strategy was developed to synthesize self-supported hybrid nanotube arrays composed of nitrogen/sulfur-codoped carbon coated sulfur-doped TiO2 nanotubes. The resulting nanoarrays demonstrated efficient sodium storage properties, showcasing the importance of rational engineering and synthesis of hollow array architectures.