Revealing the working mechanism of a multi-functional block copolymer binder for lithium-sulfur batteries

The lithium-sulfur (Li-S) battery is one of the most promising substitutes for current energy storage systems because its low cost, high theoretical capacity, and density. However, solubility intermediate products (i.e., lithium polysulfides) resultant shuttle effect lead to rapidly fading capacity a coulombic efficiency, which hinder practical application Li-S batteries. In this study, block copolymers are constructed with both an ethylene oxide unit styrene then used as binders Electrochemical performance improvements attributed synergistic effects contributed by different units copolymer. traps polysulfide, bonds strongly enhances transport ions reach capacity. Meanwhile, maintains cathode integrity improving mechanical properties elasticity copolymer accommodate large volume changes. By enabling multiple functions via in polymer chain, sulfur utilization achieved, polysulfide diffusion confined, suppressed during cycle life batteries, revealed operando ultraviolet–visible spectroscopy S K-edge X-ray absorption spectroscopy.