Sn-based halide perovskites are expected to solve the problems of shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs) in lithium-sulfur batteries (LSBs) due to its high conductivity and electrocatalytic activity, but its intrinsic catalytic mechanism for LiPSs remains to be explored. Herein, halide perovskites of Cs2SnX6 (X = Cl, Br, I) with varying halide anions are purposefully designed to unveil the halogen-induced regulatory mechanism. Theoretical calculations demonstrate that increasing the halogen atomic number induces the shift of p-band center closer to the Fermi level, which results in the localized charge distribution around halide anions, and rapid charge separation/transfer at Sn sites, enhancing the adsorptive-catalytic activity and redox kinetics of LiPSs. Experimental investigations exhibit that LSBs assembled with the Cs2SnI6 modified separator deliver a high initial capacity of 1000 mAh g‒1 at 2 C, with a minimum decay rate of 0.068% per cycle after 500 cycles. More impressively, the Cs2SnI6 battery with high sulfur loading (6.1 mg cm‒2) and low electrolyte/sulfur ratio (5.5 μL mg‒1) achieves a remarkable reversible capacity of 768.8 mAh g‒1, along with robust wide-temperature-tolerant cycling performance from −20 to 50 ºC. These findings underscore the critical role of p-band center regulation in rationally designing advanced LSBs.
