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.

中文翻译：

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作为钠离子电池高级阳极的CoS2纳米颗粒/氮掺杂石墨/碳纳米管复合材料的合成

硫化钴（CoS ₂）由于其低成本，出色的导电性和较高的理论容量，是用于高性能钠离子电池（SIB）的有希望的负极材料。然而，由于在充电/放电过程中CoS ₂阳极的巨大体积膨胀而导致的快速容量衰减和低功率密度仍然阻碍了其实际实施。在此，我们开发了一种低成本，简便且大规模的方法来制造氮杂碳层受限的结构化CoS ₂ /碳纳米管（NC @ CoS ₂ @CNTs）杂化体，并具有用于高性能SIB的新型形态。混合电极的可逆比容量为669和334 mAh g ^-1电流密度分别为200 mA g ^-1和5000 mA g ^-1时，在3000 mA g ^-1的1000个循环中，空转的循环稳定性约为空前的，约0.014％的容量衰减，史无前例。杂化电极平衡的高电化学性能可以归因于CoS ₂纳米颗粒，N掺杂碳涂层和原位生长的CNT之间的协同作用。结果表明，CoS ₂可以很好地与N掺杂的碳/碳纳米管混合材料结构一起使用，这为在实际应用中实现出色的性能提供了一种简便的方法。