Three-dimensional hierarchical urchin-like Nb2O5 microspheres wrapped with N-doped carbon: An advanced anode for lithium-ion batteries

• Urchin-like Nb 2 O 5 @N-C microspheres are prepared by two simple steps. • Polydopamine was served as carbon and nitrogen source. • Nb 2 O 5 @N-C microspheres exhibit outstanding rate and cyclic performances. Orthorhombic Nb 2 O 5 is a promising material for the anodes of lithium-ion batteries (LIBs) owing to its pseudocapacitive features, stability, and safety. However, the practical applications for Nb 2 O 5 are limited due to its poor electrical conductivity. In this work, three-dimensional (3D) urchin-like microspheres coated with N-doped carbon were synthesized by hydrothermal synthesis and then polymerized in dopamine. When evaluated as anode for LIBs, the 3D urchin-like Nb 2 O 5 @N-C composites exhibited excellent high-rate capability (146 mAh g −1 at 20 C) and stability (78 mAh g −1 at 10 C after 2900 cycles). The remarkable electrochemical performance of the Nb 2 O 5 @N-C composites was ascribed to their unique structure and the N-doped carbon coating, which prevents the electrode from structural damage, mitigates volume expansion during the charge/discharge process, and enhances the conductance of the active material.