High-performance lithium-sulfur battery enabled by microgel binders: Simultaneous achievement of robust adhesion and effective polysulfide trapping

Lithium‑sulfur (Li S) batteries have emerged as a promising next-generation energy storage technology owing to their exceptional theoretical specific capacity (1675 mAh g −1 ), high energy density (2600 Wh kg −1 ), natural abundance of sulfur, and environmental benignity. However, the practical implementation of Li S batteries faces several critical challenges, most notably the shuttle effect of soluble lithium polysulfides (LiPSs), which severely compromises cycling stability. Here, a P(MEO 2 MA- co -OEGMA) microgel-based polymeric binder (PMO) was successfully constructed via surfactant-free emulsion polymerization. Comprehensive experimental characterization coupled with theoretical calculations reveal that the PMO binder possesses superior adhesive properties, ensuring robust electrode cohesion throughout prolonged cycling. Furthermore, the three-dimensional network structure of PMO binder facilitates strong chemical interactions with LiPSs through Li O and Li N bonds, which mitigates active material loss. As a result, Li S batteries employing the PMO binder exhibit excellent electrochemical performance, delivering an initial discharge capacity of 920.8 mAh g −1 at 1C and retaining a reversible capacity of 576.6 mAh g −1 after 500 cycles, corresponding to an ultralow capacity fading rate of merely 0.074 % per cycle. This work emphasizes the essential role of microgel binder for addressing the cycling stability challenge plagued Li S batteries, providing significant implications for the development of microgel-based materials in advanced energy storage applications.