SnS/Fe7S8 heterojunction embedded in three-dimensional N, S co-doped carbon nanosheets as anode material for sodium-ion batteries with long-term cycle life

•Dense SnS/Fe7S8 nanoparticles were prepared using the electropositive Fe(OH)33+colloid to adsorb SnO32- ions.•Bimetallic sulfide heterostructure SnS/Fe7S8 nanoparticles which boosting the ion and charge transfer kinetics.•The N, S co-doped 3D carbon nanosheet can effective improve the conductivity of the SnS/Fe7S8/NS-CNs composites.•The SnS/Fe7S8/NS-CNs composites exhibits excellent cycling performance and rate capability.