Strategies and Chemistries for Designing Poly(Ethylene Oxide)-Based Solid-State Electrolytes

Abstract

Poly(ethylene oxide)-based solid polymer electrolytes (PEO-SPEs) are among the most extensively studied candidates for next-generation solid-state lithium batteries due to their favorable ion coordination, processability, and cost-effectiveness. However, their practical utilization is hindered by low room temperature conductivity, limited electrochemical stability, and vulnerability to dendrite formation. This review provides a comprehensive overview of recent advances in PEO-SPEs, focusing on polymer design strategies-including block copolymers, graft copolymers, crosslinked networks, and composite architectures through integration of organic and inorganic fillers, as well as ionic liquids.Furthermore, emerging salt chemistries such as single-ion/dual-ion conducting matrix and dual-salt systems are evaluated, in addition to the flame retardant formulations of the PEO-SPEs. By integrating insights from molecular engineering, interfacial science, and electrochemical characterization, this review highlights the synergistic pathways toward multifunctional PEO-SPEs capable of meeting the demands of high-energy, safe, and flexible solid-state lithium batteries.