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.