Iron sulfides with dopamine-derived carbon coating as superior performance anodes for sodium-ion batteries

High energy ball-milled iron sulfides with thin carbon layer coating (BM-FeS/C composites) were prepared by the simple and economical process. Ball-milled process, followed by carbon coating, reduced the particle size and increased the electrical conductivity. When employed as sodium-ion battery anodes, BM-FeS/C composites showed extremely high electrochemical performance with reversible specific capacity of 589.8 mAh·g^-1 after 100 cycles at a current density of 100 mA·g^-1. They also exhibited superior rate capabilities of 375.9 mAh·g^-1 even at 3.2 A·g^-1 and 423.6 mAh·g^-1 at 1.5 A·g^-1. X-ray absorption near edge structure analysis confirmed the electrochemical pathway for conversion reaction of BM-FeS/C composites.