MOF-Derived Fe7S8 Nanoparticles/N-Doped Carbon Nanofibers as an Ultra-Stable Anode for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have aroused wide concern due to their potential applications in large-scale energy-storage systems. In this work, a hybrid of Fe7S8 nanoparticles/N-doped carbon nanofibers (Fe7S8/N-CNFs) is designed and synthesized via electrospinning. As an anode for SIBs, Fe7S8/N-CNFs exhibit a high reversible capacity of 649.9 mAh g(-1) at 0.2 A g(-1) after 100 cycles, and superior cycling stability for 2000 cycles at 1 A g(-1) with only 0.00302% capacity decay per cycle. Such excellent performance originates from: i) Fe7S8 nanoparticles (average diameter of 17 nm), which shorten the Na+ diffusion distance; ii) the unique 3D N-CNFs, which enhance the conductivity, alleviate the self-agglomeration and large volume change of Fe7S8 nanoparticles, and offer numerous active sites for Na+ adsorption and paths for electrolyte diffusion. The fascinating structure and superior electrochemical properties of Fe7S8/N-CNFs shed light on developing high-performance SIBs anode materials.

Automated summary

Fe7S8/N-CNFs, as an anode for SIBs, demonstrate excellent electrochemical properties with a high reversible capacity and superior cycling stability. The superior performance can be attributed to the presence of Fe7S8 nanoparticles, which shorten Na+ diffusion distance, and the unique 3D N-CNFs, which enhance conductivity and provide active sites for Na+ adsorption and paths for electrolyte diffusion. The design of Fe7S8/N-CNFs sheds light on developing high-performance SIBs anode materials.