In-situ encapsulating FeS/Fe3C nanoparticles into nitrogen-sulfur dual-doped graphene networks for high-rate and ultra-stable lithium storage

A novel FeS/Fe3C nanoparticles encapsulated in porous nitrogen-sulfur dual-doped graphene network (FeS/Fe3C@NS-G) have been successfully fabricated via a one-step in-situ pyrolysis strategy. The nitrogen and sulfur co-doped graphene networks exhibited abundant mesoporous structure and excellent electrical conductivity, facilitating fast electron transport and lithium-ion diffusion. The heterogeneous FeS/Fe3C nanoparticles are homogeneously dispersed in the three-dimensional porous graphene shell with copious internal void space which can accommodate the volume change of the nanoparticles during electrochemical reaction. The FeS/Fe3C@NS-G nanohybrids delivered excellent reversible capacity of 1003 mAh g(-1) after 150 cycles at 0.1 A g(-1 )with a minor capacity decay rate of 1.25%. Furthermore, an ultralong cycling stability of 610 mAh g(-1) after 800 cycles at 1 A g(-1) with the capacity retention of 91.6% relative to the reversible capacity of the second cycle was observed. This remarkable lithium storage capacity of FeS/Fe3C@NS-G networks reveals their promising potential as anode materials for lithium-ion batteries. (C) 2018 Elsevier B.V. All rights reserved.