Synthesis of Zn-Pre-Intercalated VO·nHO/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 VO·nHO 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 at 0.1 A·g, and this value can still reach 210 mAh·g after 100 cycles. Additionally, it exhibits 196 mAh·g and keeps 161 mAh·g after 1200 cycles at 4 A·g. The achieved performances are much higher than that of ZnVOH and VOH. All results reveal that Zn 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 Zn migration. All findings demonstrate ZnVOH/rGO's potential as a perspective cathode material for AZIBs.