A high-rate aqueous rechargeable zinc ion battery based on the VS4@rGO nanocomposite

Abstract

Aqueous zinc ion batteries (ZIBs) have recently triggered increasing research interest because of their low cost, safety and environment friendliness, while suitable cathode materials with high energy density and long cycle life are still rare. Herein, we demonstrate the patronite form of vanadium sulfide anchored on reduced graphene oxide (VS₄@rGO) prepared via a facile hydrothermal method as a high performance cathode for ZIBs. Benefiting from the peculiar crystallographic structure of VS₄ and the superior conductivity of rGO, the VS₄@rGO electrode delivers a high capacity of 180 mA h g⁻¹ with a capacity retention of 93.3% after 165 cycles at a current density of 1 A g⁻¹. Meanwhile, a high capacity retention of 83.7% can be reached when the current density is increased from 0.2 A g⁻¹ to 2 A g⁻¹, showing excellent rate performance. A synergetic reaction mechanism consisting of intercalation and conversion is proposed for the electrochemical cycle. The assembled Zn//VS₄@rGO batteries have promising potential for practical applications.