Recyclable Covalent Organic Framework Templated Polymer Entanglement for Quasi‐Solid‐State Lithium‐Metal Batteries

Precise modulation of polymer chain entanglements, which governs the core properties of the solid polymer electrolytes (SPEs) in solid‐state lithium batteries, remains challenging due to uncontrolled polymerization processes. Here, this limitation is addressed by designing a self‐triggered single‐Li⁺‐conductive covalent organic framework (COF) with highly crystalline orientation to template the in situ polymerization of 1,3‐dioxolane (DOL). The COF's ordered pores, functionalized with initiators, regulate poly(1,3‐dioxolane) (PDOL) chain entanglement while creating a novel all‐interconnected structure favorable for ion diffusion. The resulting COF‐templated PDOL electrolyte (PDCM) exhibits exceptional ionic conductivity (1.35 mS cm −1 at 20 °C), high Li + transfer number (0.74), remarkable fire safety, and surprising steady lithium deposition even after operation for > 7 months (5000 h). PDCM bears a high‐voltage cathode (LiNi 0.8 Co 0.1 Mn 0.1 O 2 , NCM811) and functions in LiFePO 4 ||Li cells over a wide operating temperature range (−20 °C to 60 °C) and maintains excellent durability even under a large current density of 0.5C in quasi‐solid‐state lithium‐metal batteries. Notably, the COF template is readily recoverable, underscoring its scalability and industrial viability.