Multilayer Sulfide‐Electrolyte Engineering Stabilizes Interfaces for Long‐Cycling, Wide‐Temperature Lithium–Organic Solid‐State Batteries

Abstract Interfacial instability remains a key barrier for sulfide electrolyte‐based all‐solid‐state lithium–organic batteries (ASSLOBs). While prior efforts have mainly focused on improving chemical compatibility between active materials and electrolytes, the role of mechanical stress in interfacial degradation has been largely overlooked. Here, we report dibenzo[b,i]thianthrene‐5,7,12,14‐tetraone (DTT) as a conductive organic cathode integrated with a Li 6 PS 5 Cl (LPSC)‐Li 10 GeP 2 S 12 (LGPS)‐Li 6 PS 5 Cl trilayer electrolyte and a lithium metal anode. Linear sweep voltammetry (LSV), operando pressure monitoring, and in situ electrochemical impedance spectroscopy coupled with distribution of relaxation times (EIS‐DRT) reveal that the trilayer design effectively mitigates stress accumulation and suppresses interfacial degradation, while cross‐sectional backscattered scanning electron microscopy (BSEM) and energy‐dispersive X‐ray spectroscopy (EDS) confirm superior structural integrity. Benefiting from this architecture, the ASSLOB delivers 296 mAh g −1 (0.1C) with remarkable long‐term stability (90.2% retention after 4800 cycles at 2 C, 60 °C), together with excellent low‐temperature and high‐loading performance, representing the best results reported for ASSOLBs using lithium anode. Our work establishes electrolyte architecture engineering as a versatile strategy to achieve high‐rate, durable, and temperature‐resilient solid‐state batteries.