New Quasi-Solid-State Li-SPAN Battery Enhanced by In Situ Thermally Polymerized Gel Polymer Electrolytes

A lithium–sulfur (Li–S) battery is a promising candidate for an electrochemical energy-storage system. However, for a long time, it suffered from the "shuttle effect" of the intermediate products of soluble polysulfides and safety issues concerning the combustible liquid electrolyte and lithium anode. In this work, sulfide polyacrylonitrile (SPAN) is employed as a solid cycled cathode to resolve the "shuttle effect" fundamentally, a gel polymer electrolyte (GPE) based on poly(ethylene glycol) diacrylate (PEGDA) is matched to the SPAN cathode to minimize the safety concerns, and finally, a quasi-solid-state Li-SPAN battery is combined by an in situ thermal polymerization strategy to improve its adaptability to the existing battery assembly processes. The PEGDA-based GPE achieved at 60 °C for 40 min ensures little damage to the in situ battery, a good electrode–electrolyte interface, a high ionic conductivity of 6.87 × 10–3 S cm–1 at 30 °C, and a wide electrochemical window of 4.53 V. Ultimately, the as-prepared SPAN composite exerts a specific capacity of 1217.3 mAh g–1 after 250 cycles at 0.2 C with a high capacity retention rate of 89.9%. The combination of the SPAN cathode and in situ thermally polymerized PEGDA-based GPE provides a new inspiration for the design of Li-SPAN batteries with both high specific energy and high safety.