Decoupling Kinetic and Shuttle Limitations in Li─S Batteries Enabled by Temperature Responsive Functional Interlayer

ABSTRACT Lithium‐sulfur batteries (LSBs) face intertwined challenges of sluggish Li ₂ S nucleation and polysulfide shuttling, which are strongly temperature‐dependent. Here, we demonstrate that an electrocatalytic MXene interlayer can decouple these limitations by functioning differently under low, room, and elevated temperatures. Using potentiostatic nucleation studies, post‐cycling FESEM, and ex situ XPS, we reveal that at low temperatures, the MXene accelerates Li ₂ S nucleation and enhances reaction kinetics, while at high temperatures it effectively anchors polysulfides, suppressing shuttle‐induced degradation. This temperature‐responsive behavior enables stable cycling, improved sulfur utilization, and mitigates dendrite formation across a wide thermal range (−10°C–55°C). These findings provide a mechanistic framework for designing interlayers that adaptively address kinetic and shuttle limitations, offering a new strategy for high‐energy‐density LSBs capable of stable operation under diverse thermal conditions.