High-performance (NH4)2V6O16·0.9H2O nanobelts modified with reduced graphene oxide for aqueous zinc ion batteries

Ammonium vanadate has been considered as a competitive high-performance cathode material for aqueous Zn-ion batteries. However, it still suffers from insufficient rate capability and poor cyclability due to the low electronic conductivity. Herein, (NH4)2V6O16·0.9H2O nanobelts with reduced graphene oxide (RGO) modification are synthesized by one-step hydrothermal reaction. Benefiting from the addition of RGO, an excellent electrochemical performance of (NH4)2V6O16·0.9H2[email protected] nanobelts can be obtained. The (NH4)2V6O16·0.9H2[email protected] displays a high-rate capacity and a high energy density of 386 Wh/kg at 72 W/kg. In particular, after 1000 cycles at 5 A/g, the capacity remains at 322 mAh/g with 92.8% capacity retention. In addition, the key reaction mechanisms of reversible Zn2+insertion/extraction in (NH4)2V6O16·0.9H2[email protected] are clarified.