Solid polymer electrolytes: ion conduction enhancement and comprehensive frontiers

Solid polymer electrolytes (SPEs) have garnered significant research interest as promising candidates for solid-state secondary batteries, offering enhanced safety, mechanical flexibility, and intrinsic dendrite suppression capabilities. However, persistent limitations, including low Li-ion transference numbers, inadequate interface conductivity, narrow electrochemical stability windows, and insufficient long-term stability, still impede their practical implementation. This review critically examines innovative strategies in polymer chemistry and structural design to address these challenges, with a particular emphasis on enhancing the interfacial compatibility of SPE electrodes. By elucidating fundamental structure-property relationships, we highlight pathways for optimizing compositional and microstructural modifications in high-performance SPE systems.