TiN nanocrystal anchored on N-doped graphene as effective sulfur hosts for high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have become prospective candidates for next-generation energy storage owing to the high energy density and low cost. However, the sluggish kinetics of the electrochemical reaction and shuttle effect result in a rapid capacity decay. Herein, a titanium nitride nanocrystal/N-doped graphene (TiN@NG) composite is developed to host elemental sulfur. The TiN nanoparticles decorated on graphene sheets attract Li polysulfides (LiPSx) and catalyze the electrochemical reduction and oxidation of LiPSx in the discharge and charge processes, respectively. These two effects effectively restrain the dissolution of the UPS, and accelerate the electrochemical reactions, thereby, alleviating the shuttle effect. As a result, the cathode composed of TiN@NG/S delivers a remarkable reversible capacity (1390 mA h g(-1) at 0.1 C) and excellent cycling performance (730 mA h g(-1) after 300 cycles). We believe that this work can bring some inspiration for designing high-performance Li-S batteries. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.