1D Sub-Nanotubes with Anatase/Bronze TiO<sub>2</sub> Nanocrystal Wall for High-Rate and Long-Life Sodium-Ion Batteries.

Chen, Biao; Meng, Yuhuan; Xie, Fangxi; He, Fang; He, Chunnian; Davey, Kenneth; Zhao, Naiqin; Qiao, Shi-Zhang · Adv Mater · 2018

basic_science · Level V

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Abstract

The development of 1D nanostructures with enhanced material properties has been an attractive endeavor for applications in energy and environmental fields, but it remains a major research challenge. Herein, this work demonstrates a simple, gel-derived method to synthesize uniform 1D elongated sub-nanotubes with an anatase/bronze TiO<sub>2</sub> nanocrystal wall (TiO<sub>2</sub> SNTs). The transformation mechanism of TiO<sub>2</sub> SNTs is studied by various ex situ characterization techniques. The resulting 1D nanostructures exhibit, synchronously, a high aspect ratio, open tubular interior, and anatase/bronze nanocrystal TiO<sub>2</sub> wall. This results in excellent properties of electron/ion transport and reaction kinetics. Consequently, as an anode material for sodium-ion batteries (SIBs), the TiO<sub>2</sub> SNTs display an ultrastable long-life cycling stability with a capacity of 107 mAh g<sup>-1</sup> at 16 C after 4000 cycles and a high-rate capacity of 94 mAh g<sup>-1</sup> at 32 C. This a high-rate and long-life performance is superior to any report on pure TiO<sub>2</sub> for SIBs. This work provides new fundamental information for the design and fabrication of inorganic structures for energy and environmental applications.