Synthesis of CoS2 Nanoparticles/Nitrogen‐Doped Graphitic Carbon/Carbon Nanotubes Composite as an Advanced Anode for Sodium‐Ion Batteries

Cobalt sulfide (CoS2) is a promising anode material for high‐performance sodium‐ion batteries (SIBs) because of its low cost, excellent electrical conductivity, and high theoretical capacity. The practical implementation of a CoS2 anode, however, is still hindered by fast capacity decay and low power density caused by its huge volume expansion during the charging/discharging process. Herein, we developed a low‐cost, facile and large‐scale method to fabricate a nitrogen‐doped carbon‐layer‐constrained structured CoS2/carbon nanotubes (NC@CoS2@CNTs) hybrid with a novel morphology for high‐performance SIBs. The hybrid electrode has reversible specific capacities of 669 and 334 mAh g−1 at the current densities of 200 mA g−1 and 5000 mA g−1, respectively, and an unprecedented cycling stability of approximately 0.014 % capacity decay per cycle over 1000 cycles at 3000 mA g−1. The balanced high electrochemical performance for the hybrid electrode can be attributed to the synergetic effect among the CoS2 nanoparticles, N‐doped carbon coating and in situ grown CNTs. The results demonstrate that the CoS2 can be well utilized with the N‐doped carbon/carbon nanotubes hybrid material structure, which provides a facile approach to realize excellent performance for practical applications.