Polysulfide shuttling and dendrite growth are two primary challenges that significantly limit the practical applications of lithium−sulfur batteries (LSBs). Herein, a three-in-one strategy for a separator based on a localized electrostatic field is demonstrated to simultaneously achieve shuttle inhibition of polysulfides, catalytic activation of the Li−S reaction, and dendrite-free plating of lithium ions. Specifically, an interlayer of polyacrylonitrile nanofiber (PNF) incorporating poled BaTiO 3 (PBTO) particles and coating with a layer of MoS 2 (PBTO@PNF-MoS 2 ) is developed on the PP separator. Theoretical calculations and experimental work show that the electric field generated at the membrane facilitates the fast and uniform transport of Li + ions, thereby inhibiting dendrite growth. Additionally, the generated electric field promotes the MoS 2 catalytic activity toward the Li−S redox reactions, particularly by reducing the reaction barriers for both the solid−liquid and solid−solid conversions. As a result, symmetrical Li//PBTO@PNF/PP/PBTO@PNF//Li cells demonstrate remarkable stability over 1200 h, and LSBs with a PP/PBTO@PNF-MoS 2 composite separator maintain a specific capacity of 318.3 mA h g −1 after 4000 cycles at 2C, with an ultralow capacity decay rate of 0.015%. In addition, the PBTO@PNF membrane also enhances the mechanical flexibility and thermal stability of the composite separator.