Nitrogen-doped carbon nanotube encapsulated Fe ₇ S ₈ was successfully used as a promising cathode for the high-efficiency and selective removal of Pb ²⁺ ions.

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.

The current Special Issue, entitled “Friction, Corrosion and Protection of Material Surfaces”, aims to discuss the state-of-the-art research progress regarding the friction and corrosion behaviors of new materials and advanced protective materials or technologies, with a special focus on the understanding of underlying friction and corrosion mechanisms and modification approaches of material surfaces against friction and corrosion in order to guide the design and preparation of materials with high performance for practical applications