A Keggin Al-13-Montmorillonite Modified Separator Retards the Polysulfide Shuttling and Accelerates Li-Ion Transfer in Li-S Batteries

The commercialization of Li-S batteries as a promising energy system is terribly impeded by the issues of the shuttle effect and Li dendrite. Keggin Al13-pillared montmorillonite (AlMMT), used as the modified film of the separator together with super-P and poly (vinylidene fluoride) (PVDF), has a good chemical affinity to lithium polysulfide (LiPS) to retard the polysulfide shuttling, excellent electrolyte wettability, and a stable structure, which can improve the rate capability and cycling stability of Li-S batteries. Density function theory (DFT) calculations reveal the strong adsorption ability of AlMMT for LiPS. Consequently, the modified film allows Li-S batteries to reach 902 mAh g(-1) at 0.2C after 200 cycles and 625 mAh g(-1) at 1C after 1000 cycles. More importantly, a high reversible areal capacity of 4.04 mAh cm(-2) can be realized under a high sulfur loading of 6.10 mg cm(-2). Combining the merits of rich resources of montmorillonite, prominent performance, simple operation and cost-effectiveness together, this work exploits a new route for viable Li-S batteries for applications.

Automated summary

This study demonstrates the use of modified montmorillonite as a separator film to enhance the performance of Li-S batteries. The modified film effectively retards the shuttle effect and improves the rate capability and cycling stability of Li-S batteries. The results show that the modified Li-S batteries exhibit higher energy density and cycling stability under different cycling conditions.