Titanium nitride nanorod array/carbon cloth as flexible integrated host for highly stable lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have been regarded as promising energy-storage systems, due to their high theoretical capacity and energy density. However, the carbonaceous sulfur hosts suffer from weak binding force between the hosts and polysulfides, restricting the cyclic stability of sulfur electrode. Meantime, the presence of binder and conductive agent in the traditional electrode reduces its energy density. This study demonstrates that titanium nitride (TiN) nanorod array on carbon cloth (CC) is employed as a flexible host for highly stable Li-S batteries via solvothermal synthesis-nitridation strategy. On the one hand, the flexible integrated network composed of three-dimensional TiN nanorod array and CC significantly improves the conductivity, increases the electron transport and electrolyte penetration of cathode. On the other hand, the 3D structure of TiN/CC and the enhanced polarity of TiN effectively strengthen the physical and chemical double adsorption for polysulfides. As a result, the combination of TiN nanorod array and CC synergistically promotes sulfur utilization and electrochemical performances of S@TiN/CC cathode. A discharge capacity of 1015.2 mAh center dot g(-1) at 0.5C after 250 cycles and 604.1 mAh center dot g(-1) at 3C after 250 cycles is realized. Under a larger current density of 5C, the resulting S@TiN/CC cathode maintains a high discharge capacity of 666.6 mAh center dot g(-1) and the Coulombic efficiency of about 100%.

Automated summary

This study demonstrates that the TiN nanorod array on carbon cloth can be used as a flexible host for highly stable Li-S batteries. The combination of TiN/CC improves conductivity, enhances polysulfide adsorption, and boosts the electrochemical performance of the battery.