Polymer electrolytes for Li-S batteries: polymeric fundamentals and performance optimization

Abstract Lithium-sulfur (Li-S) batteries have been considered as one of the most promising candidates to traditional lithium ion batteries due to its low cost, high theoretical specific capacity (1675 mAh g-1) and energy density (2600 Wh kg-1) of sulfur. Compared with traditional liquid electrolytes, polymer electrolytes (PEs) are ever-increasingly preferred due to their higher safety, superior compatibility, long cycling stability and so on. Despite some progresses on PEs, however, there remain lots of hurdles to be addressed prior to commercial applications. This review begins with native advantages for PEs to replace LEs, and then proposes the ideal requirements for PEs. Furthermore, a brief development history of typical PEs for Li-S batteries is presented to systematically summarize the recent achievements in Li-S batteries with PEs. Noted that the structure-performance relationships of polymer matrixes for PEs are highlighted. Finally, the challenges and opportunities on the future development of PEs are presented. We hold the view that composite polymer electrolytes in virtue of the high ionic conductivity and the compatible interfacial property will be promising solution for high performance Li-S batteries.