Closed-loop recyclable interfacial growth polymerization enables scalable and economical quasi-solid-state lithium metal batteries

In situ polymerization enables a scalable path to quasi-solid-state lithium metal batteries (SSLMBs), yet conventional initiators face stability, interface, and energy consumption issues. We report an interfacial growth polymerization (IGP) strategy, operating ambiently without external energy. Using molybdenum disulfide (MoS₂) to trigger 1,3-dioxolane (DOL) polymerization, we fabricate organic-inorganic composite gel electrolytes. IGP ensures high storage stability and enables closed-loop MoS₂ recycling (>95% recovery, multi-cycle reuse). The S-Mo charge gradient at composite interfaces regulates ion transport and promotes an inorganic-rich solid electrolyte interphase (SEI), suppressing dendrites and improving stability. The resulting electrolyte shows high ionic conductivity and extends Li metal cycling over 3,000 h. Roll-to-roll coating allows industrial IGP separator production at $0.67 m⁻². Ah-level pouch cells achieve stable cycling with an energy density of 418 Wh kg⁻¹. This work provides a scalable, economical, and sustainable paradigm for high-performance quasi-solid-state batteries.