Synthesis of Flower-Like Nb2Se9 as High-Performance Anode Materials for Lithium-Ion and Sodium-Ion Batteries

In this work, a flower-like Nb2Se9 material was obtained by a simple oil-phase-assisted synthesis route and used as an anode in lithium-ion and sodium-ion batteries first. It exhibited a high charge capacity (672.35 mAh g(-1) at 100 mA g(-1)), good cycling stability (596.63 mAh g(-1) after 250 cycles at 100 mA g(-1)), and outstanding rate performance (285 mAh g(-1) at 5 A g(-1)) in lithium-ion batteries. Meanwhile, the ex situ X-ray diffraction result reveals that the lithium storage mechanism of Nb2Se9 is the conversion reaction. As an anode for sodium-ion batteries, Nb2Se9 delivered an initial reversible capacity of 342.60 mAh g(-1) at the current density of 100 mA g(-1) and was stabilized at 230.36 mAh g(-1) over 500 cycles after the initial 50 cycles. Excellent electrochemical performance may be attributed to the special micro-nano hierarchical structure of the flower-like Nb2Se9 material, which greatly promotes ion diffusion and provides abundant active sites. These results indicate that flower-like Nb2Se9 is a promising anode material for both lithium-ion and sodium-ion batteries.