Simultaneously tailoring material structure and surface for robust sodium storage: A case study of TiO2

Modulating the atomic structure and surface property represents a pivotal and intriguing approach to tailoring the energy storage performance of battery materials, but their simultaneous modulation via simple processes remains a grand challenge. Taking TiO2 as an example, here we report the structure and surface modulation through a simple two-step operation, hydrogenation and fluorination, which impart high electrical conductivity and robust surface activity to the material. Hydrogenation introduces Ti3+ species in the TiO2 bulk to accelerate electron transport, while surface fluorination speeds up sodium-ion reaction dynamics. This modulated TiO2 exhibits robust Na+ storage, affording 181 mAh g( -1) over 2500 cycles at a high rate of 20 C. In addition, when paring with a commercial Na3V2(PO4)(2)O2F cathode, the designated TiO2 allows the full cell to deliver a remarkable power of 3700 W kg (-1), outperforming most sodium -ion batteries. The correlation between the robust performance and the material property is understood through energy band analysis and density functional theory calculations. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This article reports a simple two-step operation, hydrogenation and fluorination, to modulate the structure and surface of TiO2, resulting in high electrical conductivity and robust surface activity. The modulated TiO2 exhibits strong performance in sodium-ion storage, and when paired with a commercial cathode, it achieves higher power output.