Progress and perspectives on molecular design of crosslinked polymer electrolytes for solid-state lithium batteries

Solid-state polymer electrolytes (SPEs) coupling with high-specific-energy cathodes/anodes are candidate schemes for meeting the safety and energy density needs of next generation lithium batteries due to the reinforced mechanical/chemical and electrochemical stability. However, many pressing challenges, such as low ionic conductivity, large interfacial resistance and side reactions, hindering their practical applications in solid-state lithium batteries (SSLBs). Crosslinked SPEs as one of the most attractive structures exhibit many advantages, such as superior mechanical strength, thermal/chemical stability, and reduced crystallinity. The design/synthesis strategies of crosslinked SPEs and how do the geometric structural parameters affect electrochemical performance of the SPEs are not fully understood. This review comprehensively summarizes the very recent advances of crosslinked SPEs for SSLBs by discussing the related publications, which involves physical and chemical crosslinking strategies. The selection of crosslinked monomers and reaction type are classified in detail. The relationships between crosslinking structures and physical/electrochemical properties at molecular level are comprehensive analyzed. Finally, the challenges and future prospects of crosslinked SPEs in this rapidly evolving field are outlined. Overall, this review is expected to serve as a guide for designing high-performance crosslinked SPEs, and will receive widespread attention in the field of binders, separators, hydrogels, electronic skin and engineering plastics.