Abstract
Solid-state lithium-oxygen batteries (SSLOBs) are offering unparalleled safety and exceptional electrochemical performance. Despite their promise, composite solid electrolytes (CSEs) fabricated through mechanical hybridization consistently manifest pronounced ceramic particle aggregation. In this study, a thin and flexible CSE is developed by integrating Li(10)GeP(2)S(12) (LGPS) with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and implementing silane coupling agents to form a bridging framework across the organic-inorganic heterojunction interfaces. The engineered CSE exhibited remarkable room-temperature ionic conductivity reaching 1.05 × 10(-4) S cm(-1), superior electrochemical stability within an expanded voltage window extending to 4.9 V versus Li/Li(+). Furthermore, lithium symmetrical cells revealed uniform lithium deposition/dissolution behavior over 3000 h. Integration of the thin-film CSE into SSLOBs yielded devices achieving specific discharge capacities of 12874 mAh g(-1), coupled with superior long-term operational stability throughout 120 cycles. The enhanced interfacial adhesion forces observed between the heterogeneous phases play a pivotal role in maintaining space charge region stability, subsequently promoting accelerated lithium-ion diffusion kinetics while optimizing charge transfer processes at the electrochemical interfaces. The systematic study presents an innovative synthetic strategy for engineering dimensionally-confined, sulfide-enriched CSEs.