Advanced Aqueous Zinc-Ion Batteries Enabled by Three-Dimensional Amorphous Vanadium Pentoxide@Graphene Microspheres

Abstract

Aqueous zinc-ion batteries (AZIBs) already become a potential candidate for high-efficiency energy storage in view of inherent safety and abundant zinc reserves. Nevertheless, the progress of AZIBs cathode materials with excellent comprehensive performance still retains formidable challenges. Herein, the three-dimensional amorphous vanadium pentoxide@graphene (3D a-V2O5@graphene) microspheres were prepared and investigated as the cathode material of AZIBs. The amorphous characteristics of a-V2O5 and the three-dimensional graphene framework with outstanding conductivity synergistically enabled the 3D a-V2O5@graphene microspheres to expose more active sites and achieve rapid ion/electron transfer. Consequently, the obtained a-V2O5@graphene presented a promising specific capacity of 518 mAh g–1 under 0.5 A g–1 and a stable long-term cycle with an eminent remaining capacity of 177 mAh g–1 over 2000 cycles under 40 A g–1. Meanwhile, the storage mechanism also was illuminated by various ex situ characterization tests. Hence, this study provides a new viewpoint for the design of advanced AZIBs based on amorphous cathode materials.