Engineering TiO2-TiS2 heterostructure decorated on S, O-functionalized MXene as multifunctional interlayer for high-performance lithium-sulfur batteries

A TiO 2 -TiS 2 heterostructure decorated on S, O-MXene was successfully constructed. • TiO 2 -TiS 2 heterostructure mitigates MXene stacking and facilitates Li + diffusion. • The design of TiO 2 /TiS 2 ratio can balance the adsorption-catalysis trade-off. • S, O functional groups on MXene offer additional anchoring and catalytic sites. • The SM-TT interlayer enhances the cycle and rate performance of Li-S batteries. The practical application of lithium-sulfur (Li-S) batteries is impeded by polysulfides shuttling and sluggish sulfur redox kinetics. Although Ti 3 C 2 T x MXene has demonstrated great potential for polysulfides adsorption and conversion, its restacking tendency significantly diminishes its practical effectiveness. To address this critical issue, we designed and fabricated a TiO 2 -TiS 2 heterostructure decorated on sulfur and oxygen-functionalized MXene (SM-TT) through a controlled sulfurization strategy. This well-engineered architecture not only suppresses MXene restacking but also constructs abundant heterointerfaces that synergistically facilitate electron and Li + transport. Moreover, the rationally designed TiO 2 /TiS 2 ratio can well balance the adsorption-catalysis trade-off of polysulfides. Additionally, the sulfur and oxygen functional groups on MXene surface provide additional active sites for polysulfides anchoring and catalytic conversion. When employed as multifunctional interlayer in Li-S batteries, the SM-TT interlayer enables the cell to deliver a high initial capacity of 1292.8 mAh g −1 at 0.1C, maintain 768.6 mAh g −1 after 100 cycles, and exhibit 604.7 mAh g −1 at 1 C. Even under 5 mg cm −2 high sulfur loading, the cell still retains stable capacity of 722.7 mAh g −1 after 100 cycles. This work demonstrates an effective heterointerface engineering strategy for developing high-performance Li-S batteries. Download: Download high-res image (163KB) Download: Download full-size image