Synthesis of Zn2+-Pre-Intercalated V2O5·nH2O/rGO Composite with Boosted Electrochemical Properties for Aqueous Zn-Ion Batteries

Layered vanadium-based materials are considered to be great potential electrode materials for aqueous Zn-ion batteries (AZIBs). The improvement of the electrochemical properties of vanadium-based materials is a hot research topic but still a challenge. Herein, a composite of Zn-ion pre-intercalated V2O5·nH2O combined with reduced graphene oxide (ZnVOH/rGO) is synthesized by a facile hydrothermal method and it shows improved Zn-ion storage. ZnVOH/rGO delivers a capacity of 325 mAh·g-1 at 0.1 A·g-1, and this value can still reach 210 mAh·g-1 after 100 cycles. Additionally, it exhibits 196 mAh·g-1 and keeps 161 mAh·g-1 after 1200 cycles at 4 A·g-1. The achieved performances are much higher than that of ZnVOH and VOH. All results reveal that Zn2+ as "pillars" expands the interlayer distance of VOH and facilitates the fast kinetics, and rGO improves the electron flow. They both stabilize the structure and enhance efficient Zn2+ migration. All findings demonstrate ZnVOH/rGO's potential as a perspective cathode material for AZIBs.