Hierarchical Primary‐Secondary Coordination Synchronizes Ion Flux and Sulfur Redox in Solid Polymer Electrolytes

ABSTRACT

Lithium‐sulfur (Li‐S) batteries suffer from transport‐conversion imbalance, leading to concentration polarization, incomplete sulfur reduction, and unstable Li metal interfaces. Here, a coordination‐engineered polymer electrolyte with a hierarchical primary‐secondary Li ⁺ coordination architecture is developed to synchronize ion transport and sulfur redox kinetics. A CO ₂ ‐derived poly(propylene carbonate)‐based ionic framework integrates crown ether primary coordination sites with distributed carbonate secondary motifs, promoting Li salt dissociation while sustaining dynamic Li ⁺ migration. Spectroscopic and electrochemical analyses reveal redistributed Li ⁺ solvation, weakened Li ⁺ ‐TFSI ⁻ association, and enhanced ionic conductivity on the order of 10 ⁻⁴ S cm ⁻¹ , and a Li ⁺ transference number of 0.45 at 60°C. The synchronized Li ⁺ flux suppresses concentration polarization and stabilizes sulfur conversion and Li deposition. Solid‐state Li‐S cells with a sulfur loading of ≈2.0 mg cm ^{− 2} deliver an initial discharge capacity of 766 mAh g ^{− 1} and maintain ≈60% capacity retention during cycling at 0.1 C under liquid‐electrolyte‐free conditions. This work establishes hierarchical coordination engineering as a molecular strategy for coupling ion transport with redox conversion in solid‐state battery systems.