High‐Entropy Sulfides Enable Dual‐Pathway Sulfur Conversion in PEO‐Based All‐Solid‐State Li–S Batteries

ABSTRACT All‐solid‐state lithium‐sulfur batteries (ASSLSBs) are promising for safe, high‐energy storage, but their development is limited by lithium polysulfides (LiPSs) dissolution and shuttle effect in poly(ethylene oxide)‐based solid polymer electrolytes, leading to sluggish sulfur conversion and rapid capacity decay. Herein, we report a dual‐phase high‐entropy sulfide system (HES, FeCoNiCuMoS x ) nanoflowers as a multifunctional sulfur host. Owing to lattice distortion and strong d‐p orbital coupling, HES exhibits strong chemical affinity toward LiPSs and accelerates sulfur conversion. Importantly, the dual‐phase HES enables a dual‐pathway sulfur reduction reaction, in which a restrained LiPSs‐mediated “liquid”‐phase route sustains kinetics, while a dominant “solid‐solid” (S to Li 2 S) pathway fundamentally blocks LiPSs dissolution and shuttling. As a result, the S@HES cathode delivers a high specific capacity of 1319.3 mAh g −1 at 0.1 C and maintains remarkable cycling stability with a low capacity decay rate of only 0.0458% per cycle over 1000 cycles at 1 C, along with stable electrochemical performance over the investigated temperature range of 40°C to 60°C. Furthermore, S@HES‐based pouch cells exhibit excellent mechanical flexibility and deliver a high initial capacity of 1365.8 mAh g − 1 with stable cycling performance, collectively underscoring the strong potential of this dual‐pathway regulation strategy for practical advanced ASSLSBs.