Insight into Lithium–Sulfur Batteries with Novel Modified Separators: Recent Progress and Perspectives

Lithium-sulfur (Li-S) batteries have been found to have sky-scraping theoretical gravimetric energy density and have gained a lot of interest. However, owing to low electrical conductivity, a conducting substance must be coupled with the sulfur cathode. The first important concern in Li-S is diffusion of lithium polysulfides (PSs), resulting in a shuttle linking both the cathode and anode and rapid capacity of degradation. Plating conventional separators is a kind of alleviation of the shuttle issue. To achieve an advanced Li-S battery, understanding of the structure of PSs needs to be considered to design efficient separator coating materials. The main object of this work is to review the most promising recent challenges and address the application of modified coatings on the polypropylene (PP), polyethylene (PE), and glass fiber (GF) separators for high-performance Li-S batteries. The particular focus has been placed on functioning of various functional layers on the surface of PP, PE, and GF, including polymers, carbons, nanomaterials, and their composites. Finally, the polar host materials in the cathode that influence the Li-S performance are summarized. © 2021 American Chemical Society. All rights reserved.