Design of an Ultra-Highly\nStable Lithium–Sulfur\nBattery by Regulating the Redox Activity of Electrocatalyst and the\nGrowth of Lithium Dendrite through Localized Electric Field

Polysulfide shuttling and dendrite growth are two primary\nchallenges\nthat significantly limit the practical applications of lithium–sulfur\nbatteries (LSBs). Herein, a three-in-one strategy for a separator\nbased on a localized electrostatic field is demonstrated to simultaneously\nachieve shuttle inhibition of polysulfides, catalytic activation of\nthe Li–S reaction, and dendrite-free plating of lithium ions.\nSpecifically, an interlayer of polyacrylonitrile nanofiber (PNF) incorporating\npoled BaTiO<sub>3</sub> (PBTO) particles and coating with a layer\nof MoS<sub>2</sub> (PBTO@PNF-MoS<sub>2</sub>) is developed on the\nPP separator. Theoretical calculations and experimental work show\nthat the electric field generated at the membrane facilitates the\nfast and uniform transport of Li<sup>+</sup> ions, thereby inhibiting\ndendrite growth. Additionally, the generated electric field promotes\nthe MoS<sub>2</sub> catalytic activity toward the Li–S redox\nreactions, particularly by reducing the reaction barriers for both\nthe solid–liquid and solid–solid conversions. As a result,\nsymmetrical Li//PBTO@PNF/PP/PBTO@PNF//Li cells demonstrate remarkable\nstability over 1200 h, and LSBs with a PP/PBTO@PNF-MoS<sub>2</sub> composite separator maintain a specific capacity of 318.3 mA h g<sup>–1</sup> after 4000 cycles at 2C, with an ultralow capacity\ndecay rate of 0.015%. In addition, the PBTO@PNF membrane also enhances\nthe mechanical flexibility and thermal stability of the composite\nseparator.