Abstract:

Sodium?ion batteries（SIBs） have broad application prospects in large?scale energy storage due to their high element abundance and low cost.Therefore，it is of great significance to explore potential electrode materials adapted to sodium?ion batteries.Among them，iron sulfide in high capacity conversion anode materials has attracted much attention due to its advantages of high element abundance，low cost and environmental friendliness.Using reactive scarlet dye as carbon source，2 nm ultra?thin nitrogen and sulfur doped carbon materials coated iron disulfide（FeS₂/N，S-C） micron particle composites were synthesized by solvent impurity removal and high temperature annealing.The three?dimensional conductive carbon network and heteroatomic doping promoted the rapid electron conduction，effectively alleviated the volume expansion during the sodium storage process of FeS₂.At the same time，the very low carbon content（~4%） helped to improve the mass and volumetric energy density of the electrode or cell.The results showed that the FeS₂/N，S-C electrode had high reversible specific capacity（758 mA·h/g at 0.1 A/g） and excellent rate performance（207 mA·h/g at 10 A/g）.This work not only provided a potential low?cost composite anode material for sodium?ion batteries，but also explored a new idea of efficient N-doped carbon coating.

Key words: ultra?thin carbon layer, N and S doping, FeS₂, sodium?ion battery, anode material