Synthesis of self-supported V2O5-coated graphite felt composite cathode for high-performance zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have promising for large-scale energy storage due to their low cost and high safety. However, the slow migration rate and strong electrostatic repulsion of Zn²⁺ impose stringent requirements on the selection of cathode material. Therefore, the development of suitable cathode materials is crucial for the further advancement of AZIBs, playing a vital role in reducing costs and enhancing electrochemical performance. Vanadium pentoxide (V₂O₅) exhibits potential for energy storage due to its relatively high theoretical specific capacity. This study proposes an in-situ synthesis strategy to directly grow V₂O₅ nanostructures onto a graphite felt (GF) substrate, constructing a self-supported, binder-free V₂O₅@GF composite cathode. The high electrical conductivity of GF serves as a three-dimensional conductive network, effectively promoting electron transfer kinetics between the active material and the electrolyte, and enhancing the structural integrity of the cathode material, thus significantly improving electrochemical cycling stability. As a cathode material for AZIBs, V₂O₅@GF demonstrates impressive discharge specific capacity (507 mAh/g at 0.2 A/g), along with outstanding rate capability (165 mAh/g at 5 A/g), and a long-cycling life (86.5% capacity retention after 2000 cycles at 4 A/g). This study provides a new approach and direction for the high-specific-capacity development of AZIBs.