In-situ XRD study of the structure and electrochemical performance of V2O5 nanosheets in aqueous zinc ion batteries

摘要

Rechargeable zinc ion batteries that use mild aqueous electrolyte are attracting extensive attention for large scale energy storage due to cost and safety concerns. However, the research for the suitable cathode materials in which host zinc ions reversibility insert and extract is still under developing. In this work, we report V2O5 nanosheets as cathode material for zinc ion battery with mild aqueous ZnSO4 electrolyte. The V2O5 nanosheets were synthesized by freeze-drying process using sol-gel as precursor. The structures and morphology of the materials were characterized by XRD and FESEM analysis. FESEM demonstrated that the sample displayed leaflike sheet morphology. The XRD was indexed to an orthorhombic V2O5 phase. The electrochemical performance of V2O5 nanosheets cathode in aqueous zinc ion battery was measured by galvanostatic charge-discharge test and cyclic voltammetry. As a result, the cathode delivered a maximum specific discharge capacity of 318.4 mAh g(-1) at a current density of 1.0 A g(-1) and a long cycle life up to 2000 cycles. Meanwhile, in-situ and ex situ XRD analysis showed that the structure of V2O5 nanosheets underwent an irreversible phase transformation after the initial charge and discharge process.