Sn-doped hierarchical flower-like MoSe2/NC embedded in N-doped carbon for fast and durable sodium ion storage

In this study, Sn-doped MoSe2 nanosheets were grown on nitrogen-doped carbon substrate (Sn-MoSe2/NC) to assemble into hierarchical flower-like porous hollow microspheres. The as-obtained composites could maintain a stable sodium ion storage performance of 305 mAh g- 1 at 1 A g- 1 for 600 cycles, and even had 214 mAh g- 1 at a current of 5 A g- 1, with 95 % of the capacity retained for 8000 cycles. Thanks for synergistic doping strategies, the electronic conductivity was increased by the enlarged layer spacing. Meanwhile, the volume tension caused by the insertion and extraction of sodium ions could be released and absorbed by the hollow structure. Furthermore, MoSe2 and nitrogen-doped carbon had a strong interfacial connection through Mo-N bonding, which helped to enhance the stability of the structure.