Enhanced Sodium Storage Performance of Floral Spherical Vanadium Disulfide by Ether‐Based Electrolyte and Copper Collector Inducing

Abstract Vanadium disulfide (VS 2 ) emerges as a great potential anode material for sodium‐ion batteries (SIBs) owing to its large layer spacing and high specific capacity. However, the severe capacity decay and ambiguous sodium storage mechanism severely impair its merits. Herein, the nano‐micro floral spherical VS 2 is designed and its performance enhancement mechanism in ether‐based electrolyte is deciphered. The VS 2 anode in ether‐based electrolyte undergoes multiple sodium storage mechanisms, involving a traditional reaction of VS 2 ↔NaVS 2 ↔Na 2 S and a unique reaction of Na 2 S↔Na 2 S x (2 < x <8) ↔S 8 facilitated by the Cu collector. Meanwhile, multiple reactions trigger decomposition‐reassembly of the original structure to form the hierarchical porous framework that mitigates the stress generated by volume changes. Notably, molecular dynamics simulations and electrochemical measurements indicate that the ether‐based electrolyte not only facilitates Na + de‐solvation and diffusion, but also endows the VS 2 electrode with speedy Na + diffusion kinetics. Consequently, the VS 2 electrode in ether‐based electrolyte demonstrates an outstanding reversible capacity of 655.8 mAh g −1 after 900 cycles at ultra‐high 20 A g −1 . In addition, the assembled Na 3 V 2 (PO 4 ) 3 //VS 2 full battery achieves superior cycling stability with an average capacity decayed rate of only 0.069% per cycle. This work can provide precious insights into the development of advanced metal‐sulfide anode materials.