Conducting Polymers Meet Lithium-Sulfur Batteries: Progress, Challenges, and Perspectives

Lithium-sulfur (Li-S) batteries have attracted increased interest because of the high theoretical energy density, low cost, and environmental friendliness. Conducting polymers (CPs), as one of the most promising materials used in Li-S batteries, can not only facilitate electron transfer and buffer the large volumetric change of sulfur benefiting from their porous structure and excellent flexibility, but also enable stronger physical/chemical adsorption capacity toward polysulfides (LiPSs) when doped with abundant heteroatoms to promote the sulfur redox kinetics and achieve the high sulfur loading. This review firstly introduces the properties of various CPs including structural CPs (polypyrrole (PPy), polyaniline (PANi), polyethylene dioxothiophene [PEDOT]) and compound CPs (polyethylene oxide (PEO), polyvinyl alcohol (PVA) and poly(acrylic acid) [PAA]), and their application potential in Li-S batteries. Furthermore, the research progress of various CPs in different components (cathode, separator, and interlayer) of Li-S batteries is systematically summarized. Finally, the application perspective of the CPs in Li-S batteries as a potential guidance is comprehensively discussed.