TiO2-Ti3C2Tx MXene@CNTs hybrids modified polypropylene separator for high-performance lithium‑sulfur battery

Lithium‑sulfur (Li S) batteries are regarded as a potential candidate of next-generation energy storage devices. However, the poor long-term cycling performance arose from shuttle effect remains a challenge. The recent studies have shown that two dimensional (2D) MXenes have great potential in high efficient Li S cells due to strong adsorption ability for lithium polysulfides (LiPSs) and effective catalytic activity for rapid kinetics. Herein, a polypropylene separator modified by a three-dimensional (3D) TiO 2 -Ti 3 C 2 T x MXene@CNTs heterostructure using sulfur templates combined with H 2 O 2 partial oxidation treatment is proposed to alleviate the shuttle effect and improve the overall utilization efficiency of sulfur in Li S batteries. The as-prepared separator effectively enhances the LiPSs trapping ability and significantly reduces the oxidation overpotential of Li 2 S, demonstrating high catalytic efficiency and sufficient conductivity to promote the transformation of LiPS to Li 2 S and thus accelerating the transformation kinetics of Li S batteries. Remarkably, the TiO 2 -MX@CNTs modified separator with 1.3 mg cm −2 sulfur loading enables a stable capacity of 859 mAh g −1 after 300 cycles at 1C with a capacity decay rate of approximately 0.035 % per cycle, suggesting promising potential for practical applications. This work presents a new method to regulate the electrochemical performance of Li S batteries.