Iron Sulfide Quantum\nDots Decorated on Porous N‑Doped\nCarbon for Lithium/Sodium-Ion Storage

Iron sulfide is considered a potential anode material\nfor lithium-\nand sodium-ion batteries (LIBs/SIBs) in view of its natural abundance\nand high theoretical specific capacity. Nevertheless, a large volume\nexpansion and relatively poor electronic conductivity have hindered\nits application. Herein, a unique composite with iron sulfide quantum\ndots decorated on N-doped porous carbon hierarchical frameworks (FeS@NC)\nis constructed via a vulcanization-carbonization strategy. The confined\nsize of iron sulfide dots and the designed porous structure of carbon\nframeworks effectively alleviate the volume expansion issue upon ion\ninsertion, while the N-doped carbon matrix efficiently enhances the\nelectrode conductivity. Consequently, the presented FeS@NC composite\nexhibits excellent lithium/sodium storage performance. For LIBs, the\nFeS@NC electrode shows discharge capacities of 844.2 mAh/g at 0.5\nA/g after 300 cycles and 578.9 mAh/g at 5 A/g in the rate test. Moreover,\nit delivers a high discharge capacity of 460.7 mAh/g after 350 cycles\nat 1 A/g for SIBs.