One-Pot Synthesis of Quaternary Pyridinium-Type Cationic-Based Porous Organic Frameworks: Enhanced Poly(ethylene oxide) Composite Polymer Electrolytes for All-Solid-State Li–S Batteries

Two quaternary pyridinium-type cationic-based porous organic frameworks (DB-POF and LB-POF) were first synthesized via “one-pot” polymerization and were incorporated into a PEO/LiTFSI matrix as fillers to prepare a series of solid polymer electrolytes (SPEs) . The obtained quaternary pyridine-type cationic-based POFs not only have higher polarizability through the characteristic of skeleton charge but also have a stable structure and simple preparation, making them a good candidate material for achieving rapid Li+ conductivity in SPEs. Therefore, POFs could be incorporated into PEO-based SPEs that will have a positive impact on the ion transport capacity and the mechanical properties of SPEs and also increase the stability of the lithium metal anode. Among the obtained membranes, the PEO-LB-10% electrolyte exhibits the best ion conductivity, up to 5.8 × 10–4 S cm–1 at 90 °C, and has outstanding mechanical properties, and the tensile strength can reach 8.61 MPa. Significantly, the Li–S battery containing the PEO-LB-10% electrolyte indicates superior electrochemical performance, with an excellent initial discharge specific capacity of 906 mAh g–1 at 0.2 C. After 500 cycles at 1 C, its capacity remained at 472 mAh g–1, with an attenuation rate of 0.037% per cycle.