Colloidal Synthesis of Ultrathin and Se-Rich V 2 Se 9 Nanobelts as High-Performance Anode Materials for Li-Ion Batteries.

In this study, the one-dimensional (1D) material V 2 Se 9 was successfully synthesized using a colloidal method with VO(acac) 2 and Se powder as precursors in a 1-octadecene solvent. The obtained colloidally synthesized V 2 Se 9 (C-V 2 Se 9 ) has an ultrathin nanobelt shape and a 4.5 times higher surface area compared with the bulk V 2 Se 9 , which is synthesized in a solid-state reaction as previously reported. In addition, all surfaces of C-V 2 Se 9 are exposed to Se atoms, which is advantageous for storing Li through the conversion reaction into the Li 2 Se phase. Herein, the electrochemical performance of the C-V 2 Se 9 anode material is evaluated; thus, the novelty of C-V 2 Se 9 as a Se-rich 1D anode material is verified. The C-V 2 Se 9 electrode exhibits a reversible capacity of 893.21 mA h g -1 and a Coulombic efficiency of 97.82% at the 100th cycle and excellent structural stability. Compared with the bulk V 2 Se 9 electrode, the outstanding electrochemical performance of C-V 2 Se 9 is attributed to its ultrathin nanobelt shape, high surface area, shorter Li diffusion length, and more electrochemically active sites. This work indicates the great potential of the Se-rich 1D material, C-V 2 Se 9 , as a post-transition metal dichalcogenide material for high-performance LIBs.