Strongly Anchoring Polysulfides by Hierarchical Fe₃O₄/C₃N₄ Nanostructures for Advanced Lithium–Sulfur Batteries

Li–S batteries have attracted considerable interest as next-generation energy storage devices owing to high energy density and the natural abundance of sulfur. However, the practical applications of Li–S batteries are hampered by the shuttle effect of soluble lithium polysulfides (LPS), which results in low cycle stability. Herein, a functional interlayer has been developed to efficiently regulate the LPS and enhance the sulfur utilization using hierarchical nanostructure of C₃N₄ (t-C₃N₄) embedded with Fe₃O₄ nanospheres. t-C₃N₄ exhibits high surface area and strong anchoring of LPS, and the Fe₃O₄/t-C₃N₄ accelerates the anchoring of LPS and improves the electronic pathways. The combination of these materials leads to remarkable battery performance with 400% improvement in a specific capacity and a low capacity decay per cycle of 0.02% at 2 C over 1000 cycles, and stable cycling at 6.4 mg cm⁻² for high-sulfur-loading cathode.[Figure not available: see fulltext.].