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.
Keywords: Fe3O4 nanosphere; Hierarchical nanostructured C3N4; Interlayer; Lithium–sulfur battery; Long-term cycling.