Advances in poly(ethylene oxide)-based solid-state lithium-ion battery research

Solid-state lithium-ion batteries are increasingly recognized as a pivotal advancement for the next generation of energy storage technology, owing to their superior safety, high energy density, and extended cycle life. Among the various solid-state polymer materials for Li-ion batteries, poly(ethylene oxide) (PEO)-based solid-state electrolytes have garnered significant attention owing to their excellent interfacial affinity and high solubility for different lithium salts. However, PEO-based solid electrolytes continue to face obstacles, such as diminished ionic conductivity at ambient temperature, inadequate mechanical characteristics, and severe concentration polarization in practical applications. Researchers have proposed a series of modification strategies to enhance the room temperature ionic conductivity by exploring polymer copolymerization, blending, and hyperbranched methods. To optimize the mechanical properties, studies mainly focus on adding high-strength fillers, introducing cross-linking networks, and developing self-repairing materials. To mitigate the concentration polarization effect, a polyanionic configuration is introduced into the polymer backbone, accompanied by the addition of fillers having anionic receptor groups. In this review, the physicochemical properties and Li⁺ migration mechanisms of PEO-based solid polymer electrolytes are systematically described, focusing on the aforementioned modification strategies and their research progress. Additionally, it offers insights into future development trends.