Kinetically‐Enhanced Gradient Modulator Layer Enables Wide‐Temperature Ultralong‐Life All‐Solid‐State Lithium‐Sulfur Batteries

Inadequate ionic transport across the electrode/electrolyte interface hampers the lithium-sulfur reaction kinetics, thereby limiting the electrochemical performance of all-solid-state lithium-sulfur batteries (ASSLSBs). Herein, a kinetically-enhanced gradient modulator layer (KEGML) is proposed and fabricated via potential modulation. In situ/ex situ analyses reveal the optimal modulated potential difference driving the chemical reaction between Li ions and the P2S5 pre-interphase product for stabilized KEGML and maintained full-sulfur conversion. Cryo-focused ion beam-scanning electron microscopy characterization and ab-initio molecular dynamics confirm the interfacial reinforcement by gradient uniformization of ion transport and enhanced interface stability by efficiently avoiding the side effects between sulfur/sulfides solid electrolyte/carbon, respectively. As a result, an eightfold increase in ionic transport capability is achieved with KEGML at the end of the 200 cycles. Impressively, KEGML-based ASSLSBs not only accelerate the redox conversions but also display an exceptional cycling stability of a specific capacity of 1578.9 mAh g−1 for ≈1.5 years with a 99.9% capacity retention and a high areal capacity of 13 mAh cm−2 over 200 cycles, which is among the record-level. ... mehrEven in the ambient environment from 60 °C to as low as −30 °C, it exhibits excellent adaptivity attributed to the fast kinetics, shedding light on future practical applications.