Simultaneous Modification of Dragon fruit-like TiO2 Nanoarchitectures to Enhance Lithium Storage

Titanium dioxide (TiO2) is a promising anode material for lithium-ion batteries with the characteristics of highly stable structure and excellent safety, while the application is constrained by its inferior electrical conductivity and sluggish lithium-ion diffusion kinetics. Herein, H2Ti4O9 was prepared as a precursor, and it was wrapped with polyvinylpyrrolidone (PVP) as the nitrogen and carbon sources. Then, the N-doped carbon-filled TiO2 nanocrystals (N-TiO2/C), which had a unique dragon fruit structure with TiO2 nanocrystals acting as seeds and carbon acting as the flesh, were successfully prepared from PVP-coated H2Ti4O9 by one-step heat treatment. It is noteworthy that four modification methods, including carbon filling, nanosizing, nitrogen doping, and morphological designing, are all accomplished simultaneously during this process. The N-TiO2/C composite exhibits an outstanding stable capacity of 444.6 mAh g–1 after 600 cycles at 1 A g–1, and it possesses a reversible capacity of 146.7 mAh g–1 at 5 A g–1. The superior electrochemical capacity can be attributed to the distinctive dragon fruit structure along with nitrogen doping and carbon filling. The ingenious modification strategy can extend to the investigation on the other oxide anode materials.