Abstract 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 Al 13 ‐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.