A Durable Na0.56V2O5 Nanobelt Cathode Material Assisted by Hybrid Cationic Electrolyte for High-Performance Aqueous Zinc-Ion Batteries

Abstract

Rechargeable aqueous Zn-ion batteries (ZIBs) show attractive potential in energy storage devices on account of high safety and eco-friendliness. Yet the lack of suitable cathode materials prevented the practical application of ZIBs. In our work, a Na0.56V2O5 (NVO) nanobelt cathode material has been fabricated via a hydrothermal reaction. The prepared NVO samples reveal an expanded layer spacing, assisted by the chemical intercalation of Na+ into the V2O5. Particularly, a mild hybrid cationic electrolyte (0.5HCE, containing 3 M ZnSO4 and 0.5 M Na2SO4) was employed to replace the traditional ZnSO4 electrolyte (ZE) in the Zn//NVO system. Owing to the enlarged interlayer spacing and the protective effect of 0.5HCE, the NVO cathode delivers a preferable capacity and good cyclic stability. More specifically, the NVO cathode in 0.5HCE displays a high initial discharge capacity of 317 mAh g−1 at 0.1 A g−1, and exhibits a good stability after 1000 cycles at the current density of 1 A g−1. Besides, the Zn//NVO battery also presents a favorable rate capability and a high reversibility. This study could provide new directions for the development of low-cost zinc ion batteries.