Heterostructured CoS2/NiS2 nanoparticles encapsulated in bamboo-like carbon nanotubes as a high performance anode for sodium ion batteries

Sodium ion batteries (SIBs) are prospective energy storage systems because of affluent sodium resources and its low cost. The appropriate electrode materials with high performance are prerequisite to satisfy actual demand for SIBs. Heterostructured electrodes show high specific capacity and rate capacity for SIBs owing to the synergistic effect of multiple components compared with single component. Here, heterostructured binary metal-sulfide CoS2/NiS2 encapsulated in bamboo-like carbon nanotubes (CoS2/NiS2@B-CNT) was prepared by pyrolysis and sulfidation procedure. This heterostructured anode material demonstrates a high capacity of 625.8 mAh g−1 at 0.1 A g−1, a distinguished rate capacity (491.6 mAh g-1 at 10 A g−1¬) and stable cyclic property (497.6 mAh g-1 at 5 A g-1 after 1000 cycles, 93.0 % capacity retention). This design of heterostructure offers a new avenue to develop anode materials with high performance for SIBs.