Carbon-encapsulated CoS2 nanoparticles anchored on N-doped carbon nanofibers derived from ZIF-8/ZIF-67 as anode for sodium-ion batteries

Utilized Zn/Co-based metal-organic framework, we successfully fabricate 1D N-doped porous carbon nanofibers anchoring amorphous and graphite carbon-encapsulated CoS2 nanoparticles, using a facile electrospinning strategy combined with annealing treatment. Remarkably, the composite as superior anode for sodium ion battery is rationally designed, and also exhibit enhanced Na-storage performance. The composite shows a large specific capacity of 876 mAh g−1 at 100 mA g−1 in the initial cycles and an outstanding long-term performance (148 mAh g−1 at a current density of 3.2 A g−1 over 1000 cycles). The improved electrochemical performance is ascribed to the 1D porous carbon nanofibers structure and the amorphous and graphite carbon coating, which can relatively inhibit agglomeration of CoS2 nanoparticles, mitigate the volume of the material changes in the process of circulation and provide stabilized electrical conductivity. This research paves the way for extending the 1D metal sulfides and metal-organic framework composites toward potential applications.