Edge-rich vertical graphene nanosheets templating V2O5 for highly durable zinc ion battery

Abstract

Zinc ion batteries (ZIBs) have attracted increasing attention due to their low cost, high safety and environmental friendliness. However, the simultaneous achievement of long cycle life and high energy density of ZIBs remains an open challenge. In this work, edge-rich cathodes with vertically orientated graphene (VG) nanosheets templating V2O5 nanosheets are designed for high-performance ZIBs. In such a hybrid structure, free-standing VGs on carbon cloth (CC) with non-aggregated characters, open networks and sharp edges as nanotemplates provide fast electron-transfer channels and large accessible surface area to electrolyte. Moreover, edge-rich Zn nanosheets are deposited on CC as anodes to match with edge-rich V2O5/VG/CC cathode. As a result, the assembled aqueous ZIB shows a high capacity of 370 mAh g−1 (at a current density of 0.2 A g−1), high rate capability (capacity retention of over 50% at a current density up to 50 A g−1) and excellent cycle life (showing a high capacity retention of 85% over 5000 cycles).