Synergistic effect of titanium‐oxide integrated with graphitic nitride hybrid for enhanced electrochemical performance in lithium‐sulfur batteries

Lithium-sulfur (Li-S) secondary batteries have been limited by the poor cyclic stability, mainly caused by the dissolution polysulfide species into the electrolyte and subsequent irreversible shuttling effect. Recently, addition of the polysulfide adsorbents within sulfur cathode is effectively improving the electrochemical performance. Herein, TiO2 integrated with g-C3N4 (TiO2@g-C3N4: TOCN) hybrid was prepared by a facile heating treatment from the precursor of urea and TiO2composites, which used as host material for elemental sulfur (TOCN@S) in Li-S batteries. The multifunctional TOCN not only reduced the electrochemical resistance but also provided strong adsorption sites to immobilize sulfur and polysulfide. As a result, the TOCN@S cathode with a sulfur content of 74.5 wt% and a sulfur loading of 3.1 mg cm−2exhibits a high initial capability of 804 mAh g−1 at 0.5°C with capacity retention of 67.2% after 500 cycles. Additionally, the composite cathode also possesses excellent high-rate performance, retaining a remarkable specific capacity of 630 mAh g−1 even at a rate of 2°C.