Fabrication of nano-solid spherical Nb2O5/nitrogen-doped carbon composite for high-performance sodium-ion battery anodes

Nano-solid spherical Nb2O5/nitrogen-doped carbon (NC) composite is obtained by the hydrothermal method followed by a calcination procedure. The Nb2O5/NC composite exhibits good rate performance and sustainable cyclic stability (144 mAh g(-1) at 1000 mAh g(-1) upon 2000 charge-discharge cycles) as an anode material in Na-ion batteries (SIBs). The excellent performance of the Nb2O5/NC composite is attributed to its unique nanosphere structure, in which Nb2O5 nanocrystals embedded in porous NC matrix can restrain agglomeration of Nb2O5 nanocrystals and ensure electrolyte accessibility, and the NC matrix can provide effective active sites and increase ions/electrons transfer. This work offers a new method to fabricate nano-solid spherical Nb2O5/NC composite with good Na+ storage property, which can be extended for synthesizing other metal oxide/NC composite as SIB anode.