(196h) Titanium Nitride Nanotube Arrays with Tunable Dimension/Sulfur Composite As Cathode Materials for Lithium Sulfur Battery with Improved Performance

Novel and highly structured materials have been pursued as sulfur-hosting materials to enhance the specific capacity and cycling stability of lithium-sulfur (Li-S) batteries. Herein, structured titanium nitride nanotubes with tunable dimensions are investigated for their performance on Li-S batteries. We firstly develop a facile method to synthesize TiN nanotubes through anodization of Ti foils and nitridation. Surface morphology and BET surface area are characterized. The change of interfacial resistance, electrochemical performance and stability of batteries are evaluated as a function of nanotube length and diameter. The best electrochemical performance in Li-S batteries observed is for the 30 μm long and 65 nm diameter TiN nanotubes, which has a high discharge capacity of 1338 mAh g^-1 after 180 cycles at 0.1 C, and with only 0.064% average capacity decay per cycle. Furthermore, increase in nanotube length from 4.5 to 30 μm and decrease in nanotube diameter from 100 to 35 nm of titanium nitride enhance capacity by 19.1% and 24.7% after 180 discharge/charge cycles, respectively. This study suggests nano-structure with tunable geometry can play a significant role in battery performance and cyclability, and that TiN nanotubes could serve as a very promising cathode material for advanced Li-S batteries.