Nitrogen and sulfur co-doped metal monochalcogen encapsulated honeycomb like carbon nanostructure as a high performance lithium-ion battery anode material

Iron sulfide based lithium primary batteries have shown commercial success in the battery market, since then it has been considered as the most promising candidate to substitute commercial carbon-based anodes for rechargeable lithium-ion batteries. Nevertheless, practical implementation of iron sulfide anode in lithium secondary battery is greatly suffered by huge volume expansion during repeated conversion process. To address these issues, we have designed a rational three-dimensional hierarchical honey comb-like iron mono-sulfide (FeS) nanoparticles (nps) encapsulated by dual heteroatoms (nitrogen and sulfur) doped carbon nanostructures (HFSC), using metal organic complex. A series of HFSC composites: compact- and free-bound carbon framework, thickness of encapsulated nanolayer carbon (∼1.5–∼3.5 nm) over FeS nps, average size distribution of FeS nps over the carbon surface- and edge-sites, amount of nitrogen (7.18–3.26 at.%) and sulfur (6.63–4.64 at.%) functionalities, have been easily controlled via synthesis temperature. The HFSC anode of desirable physiochemical properties delivers the maximum discharge capacities of 1106.9 and 616.9 mAhg⁻¹ at low and high current densities of 100 and 1100 mAg⁻¹, respectively. Further, these novel HFSC composites deliver appreciable cycle stability of 90% for 50 cycles at a moderate current density of 500 mAg⁻¹.