Molecular Engineering of Polymer Brushes Enables Lithium–Sulfur Battery Stable Operation under Ultra‐Wide Temperature Range

Abstract Achieving stable operation under a wide temperature range is a critical target for the practical applications of lithium–sulfur batteries. However, intense lithium polysulfides (LiPSs) shuttling at high‐temperature, sluggish sulfur species conversion, and inhomogeneous Li ⁺ deposition at low‐temperature severely impair the cycle lifespan of batteries. Herein, the multifunctional polymer brushes are fabricated by grafting anthraquinone‐functionalized poly(glycidyl methacrylate) brushes on graphene surfaces (G‐pGMAAQ) to simultaneously regulate the evolution of sulfur and lithium species. Combining theoretical calculations and experiments, it is revealed that G‐pGMAAQ serves as a redox mediator that reduces the LiPSs conversion energy barrier, and its unique polar brush‐like structure effectively inhibits LiPSs shuttling and homogenizes Li ⁺ flow. Hence, G‐pGMAAQ facilitates lithium–sulfur batteries stable operation in an ultra‐wide temperature range (−40–70 °C). Furthermore, the Ah‐level pouch cell achieves an energy density of 417 Wh kg ⁻¹ , demonstrating the commercial potential of polymer brushes for lithium–sulfur batteries.