In situ polymerized PDOL-based electrolytes for lithium batteries: polymerization mechanisms, structural engineering...

Solid and quasi-solid polymer electrolytes have been widely investigated for lithium batteries because of their enhanced safety and potential compatibility with high-energy-density systems. Nevertheless, practical application remains constrained by limited ion transport, insufficient electrode/electrolyte contact, and unstable interfacial evolution. Poly(1,3-dioxolane) (PDOL)-based electrolytes differ from conventional polymer electrolytes because ring-opening polymerization of 1,3-dioxolane (DOL) enables conformal polymer networks to be generated in situ from low-viscosity precursors after cell assembly. Compared with pre-formed polymer electrolytes, PDOL provides intimate electrode/electrolyte contact while minimizing electrolyte leakage. However, the electrochemical performance of PDOL electrolytes remains limited by insufficient ionic conductivity, inadequate mechanical stability, and interfacial degradation. These limitations are closely related to polymerization chemistry, network architecture, Li⁺ coordination structures, and interfacial evolution. In this review, cationic, Lewis acid-mediated, and anion-mediated DOL ring-opening polymerization pathways are systematically analyzed with particular attention to their reported relationships with electrolyte architecture, ion transport, and electrochemical performance. Subsequently, structural and interfacial engineering strategies, including surface modification, supporting frameworks, crosslinked networks, and multilayer architectures, are critically examined. Applications in lithium-sulfur batteries are further highlighted, with particular focus placed on polysulfide regulation and lithium-metal stabilization. Remaining challenges are subsequently identified, followed by research priorities involving polymerization chemistry, structural regulation, interfacial engineering, and practical evaluation.