Heterostructured Materials for Room-Temperature Na-S Batteries: Directional Design Strategies and Multifaceted Applications.

The development of room-temperature sodium-sulfur (RT Na-S) batteries is fundamentally constrained by many severe challenges, including the polysulfide shuttle effect, sluggish sulfur conversion kinetics, and unstable sodium metal anode. This comprehensive review systematically presents a universal and versatile materials design methodology, heterostructure engineering, to concurrently address these interlinked challenges. The electrochemical mechanisms of RT Na-S batteries based on different redox pathways are elaborated, with their corresponding key challenges. Followed by that, the multifunctional advantages and fundamental design principles of heterostructured materials are summarized. It is of greater importance that we pioneer to comprehensively elucidate various real applications of these tailored heterostructured materials in advanced RT Na-S batteries, involving host materials for sulfur and sodium, interface layer materials for sulfur cathode and sodium anode, solid-state electrolytes, and current collectors, etc. We conclude with critical perspectives on the unresolved scientific questions and practical hurdles, charting a pathway from laboratory-scale innovation to the realization of high-energy, long-cycle-life, and safe devices. By demonstrating how tailored heterointerfaces can regulate sulfur speciation, guide sodium electrodeposition, and accelerate reaction kinetics, this review establishes heterostructure engineering as a cornerstone for advancing RT Na-S batteries.