Chitosan-derived carbon dots introduced V2O5 nanobelts for high-performance aqueous zinc-ion battery

Aqueous zinc-ion batteries (AZIBs) exhibit bright prospect in the next generation of large-scale energy storage, but the low specific energy and poor stability hinder their practical applications, and cathode materials with high specific capacity and excellent cycle performance are still lacking. In this work, chitosan-derived carbon dots (CCDs) are introduced into V2O5 through a simple hydrothermal method, resulting in CCDs@V2O5 nanobelts with unique one-dimensional structure and excellent electrochemical performance. The CCDs@V2O5 nanobelts have been employed as the cathode materials for AZIBs, demonstrating excellent rate performance and long-term cycling stability. At current density of 0.1 A·g−1, the specific capacity of the battery is 401.4 mAh·g−1. After cycling for 400 cycles at 1 A·g−1, the specific capacity remains at 285.3 mAh·g−1. After 2000 cycles at 4 A·g−1, the specific capacity still reaches 212.30 mAh·g−1 with capacity retention rate of 83.77 %. The introduction of CCDs effectively reduces the charge transfer impedance, and promoted the diffusion rate of Zn2+. Additionally, the insertion of Zn2+ in CCDs@V2O5 electrode is reversible by ex-situ XRD and XPS characterization. This work demonstrates that CCDs@V2O5 nanobelts have significant potential as cathode materials for AZIBs, and provides a new idea for the development of CCDs in the energy fields.