Construction of CoS-encapsulated in ultrahigh nitrogen doped carbon nanofibers from energetic metal-organic frameworks for superior sodium storage

Metal-organic frameworks (MOF) derived carbon nanomaterials are arising as promising anode materials for sodium-ion batteries. However, the heteroatoms loss and aggregation during pyrolysis significantly hamper its further application. Herein, we utilized electmspinning structuring energetic MOF into nanofibers, followed by one-step sulfurization. The high content N doping (24.58 wt%) and CoS nanoparticles encapsulated carbon nanofibers with ultra-large interlayer distance (0.422 nm) were synthesized, which improved the diffusion properties and phase behavior of sodium ions. The resulting CoS/NSCNF (NSCNF for nitrogen and sulfur codoped carbon nanofibers) delivered a superior rate performance of 358.5 mAh g(-1) after 2250 cycles at 6 A g(-1) , serving as an anode for sodium-ion battery. The excellent storage performance ascribed to abundant N/S defects, enlarged carbon spacing, and the continuous one-dimensional structure of CoS/NSCNF, enhancing sodium ions storage ability contrasted with MOF-derived carbon. The density functional theory calculations further demonstrate that nitrogen-doping favors sodium ion adsorption ability of CoS/NSCNF, thereby improving storage performance.

Automated summary

Metal-organic frameworks (MOF) derived carbon nanomaterials are promising anode materials for sodium-ion batteries. This study utilized electmspinning to structure MOF into nanofibers and sulfurization to synthesize nitrogen-doped carbon nanofibers encapsulating CoS nanoparticles, resulting in improved storage performance.