Modified Separator Based on mesoporous carbon/TiO2 composites as Advanced Polysulfide Adsorber for High Electrochemical Performance Li-S Batteries

Highlights: • We develop mesoporous carbon/TiO₂ (MC/TO) composites on the surface of the pure separator. • The modified separator could adsorb the polysulfide and improve the electronic conductivity at the same time. • The MC/TO modified separator display capacity of 658 mAh g⁻¹ at 2 C over 500 electrochemical cycles. -- Abstract: Lithium-sulfur batteries have been drawn much attention for the researchers due to their high energy density low cost, and environmental friendliness. However, the severe polysulfide dissolution and poor electronic conductivity limit the actual electrochemical performance. Separator modification is considered as a promising method to enhance the electrochemical performance of lithium-sulfur batteries. Herein, we develop mesoporous carbon/TiO₂ (MC/TO) composites as the modifying materials on the surface of the pure separator. The polar metal oxide TiO₂ on the modified separator could adsorb the polysulfide while the mesoporous graphitic carbon could improve the electronic conductivity at the same time. Owing to the above merits, the lithium-sulfur batteries with MC/TO modified separator display excellent electrochemical performance with a capacity of 658 mAh g⁻¹ at 2 C over 500 electrochemical cycles. This work provides a promising strategy to design modified separator which could inhibit the polysulfide dissolution and accelerate the sulfur redox kinetics, therefore obtaining high electrochemical performance Li-S batteries.