Highlights Iron sulfide-based heterostructure in situ hybridized with nitrogen-doped carbon nanotubes was prepared through a successive pyrolysis and sulfidation approach. The as-prepared Fe7S8/FeS2/NCNT electrode exhibits superior sodium storage performance in both ester and ether-based electrolytes. The structure advantages of the electrode contribute to high electrochemical performance in the ester-based electrolyte, while fast ionic diffusion and favorable capacitive behavior result in the robust sodium storage performance in the ether-based electrolyte.