Dual-Network Quasi-Solid Polymer Electrolyte Enabling Polysulfide Immobilization and Dendrite Suppression for Stable Lithium–Sulfur Batteries

A dual-network quasi-solid polymer electrolyte (QSPE-DN) is prepared via sequential temperature-programmed cationic ring-opening polymerization and Ritter reaction, integrating crystalline poly(oxymethylene) (POM) lamellae with a chemically cross-linked PMHA (c-PMHA) network. This hierarchical architecture synergistically combines nanoscale confinement and chemisorption to suppress polysulfide shuttling, enabling the Li–S battery with negligible self-discharge capacity loss. QSPE-DN demonstrates a high Li+ transference number (0.78). It can protect the Li anode and promote dendrite-free Li deposition. The Li|QSPE-DN|S battery has an initial capacity of 1003 mAh g–1 at 0.2C and shows a low decay rate of 0.094% per cycle over 300 cycles. Further analysis confirms the structural integrity of sulfur cathodes and negligible Li2S/Li2S2 deposition on the anodes, validating effective polysulfide confinement.