Hierarchical flower-like N-doped Nb₂O₅@N-doped carbon composites as superior anodes for advanced lithium-ion batteries

Niobium pentoxide (Nb₂O₅) has garnered significant interest as a viable anode material for lithium-ion batteries (LIBs) owing to its ability to function at high rates with improved safety and large capacity. Its applications, however, are limited by its inherent poor electron conductivity. This study describes the effective fabrication of flower-shaped N-doped Nb₂O₅ microspheres coated with N-doped carbon via a hydrothermal technique, followed by a carbonization procedure that utilizes polydopamine as a nitrogen and carbon source. When employed as the anode for LIBs, the N-Nb₂O₅ @N-C demonstrated exceptional rate capability of 158 mAh g⁻¹ at 20 C. It also demonstrated exceptional cycling stability by retaining 81% of its original capacity at 10 C after 2500 cycles. Additionally, the lithium-ion full battery using the N-Nb₂O₅ @N-C anode exhibited also excellent electrochemical properties. The remarkable electrochemical performance of the N-Nb₂O₅ @N-C composites can be attributed to the synergistic effect of the N-doped carbon coating, N doping, and a unique hierarchical structure. These factors collectively enhanced the electrochemical reaction kinetics of the N-Nb₂O₅ @N-C composite.