Attenuating the Polysulfide Shuttle Mechanism by Separator Coating

Abstract

Lithium‐sulfur batteries have a high energy density but lack cycle stability to reach market maturity. This is mainly due to the polysulfide shuttle mechanism, i.e., the leaching of active material from the cathode into the electrolyte and subsequent side reactions. We demonstrate how to attenuate the polysulfide shuttle by magnetron sputtering molybdenum oxysulfide, manganese oxide, and chromium oxide onto microporous polypropylene separators. The morphology of the amorphous coatings was analyzed by SEM and XRD. Electrochemical cyclization quantified how these coatings improved Coulombic efficiency and cycle stability. These tests were conducted in half cells. We compare the different performances of the different coatings with the known chemical and adsorption properties of the respective coating materials.

Advanced Separator Materials for Enhanced Electrochemical Performance of Lithium–Sulfur Batteries: Progress and Prospects

“…These techniques provide valuable insights into the behavior of the sulfur redox reaction and the transformations of polysulfide phases. 155 Ai et al 156 used a homemade in situ separator compression device and a dual beam−focused ion beam−SEM system to investigate the actual microstructural evolution of the separator material and demonstrate its inhomogeneity. They accurately tracked the volumetric and micro−morphological changes of the active material particles during the charge−discharge process using in situ SEM and energy−dispersive X−ray spectroscopy while repeatedly disassembling the battery electrodes.…”

“…However, they can be easily reversed. Chemical capture methods involve a reaction between some materials and LiPSs through polarity–polarity interactions and Lewis acid–base interactions, converting LiPSs into stable compounds and reducing their dissolution and diffusion. − …”

“…These may include in situ transmission electron microscopy, in situ XRD, in situ Raman spectroscopy, and in situ visualization of optical images. These techniques provide valuable insights into the behavior of the sulfur redox reaction and the transformations of polysulfide phases …”