H 2 V 3 O 8 Nanowire/Graphene Electrodes for Aqueous Rechargeable Zinc Ion Batteries with High Rate Capability and Large Capacity

Abstract Aqueous rechargeable zinc ion batteries are considered a promising candidate for large‐scale energy storage owing to their low cost and high safety nature. A composite material comprised of H 2 V 3 O 8 nanowires (NWs) wrapped by graphene sheets and used as the cathode material for aqueous rechargeable zinc ion batteries is developed. Owing to the synergistic merits of desirable structural features of H 2 V 3 O 8 NWs and high conductivity of the graphene network, the H 2 V 3 O 8 NW/graphene composite exhibits superior zinc ion storage performance including high capacity of 394 mA h g −1 at 1/3 C, high rate capability of 270 mA h g −1 at 20 C and excellent cycling stability of up to 2000 cycles with a capacity retention of 87%. The battery offers a high energy density of 168 W h kg −1 at 1/3 C and a high power density of 2215 W kg −1 at 20 C (calculated based on the total weight of H 2 V 3 O 8 NW/graphene composite and the theoretically required amount of Zn). Systematic structural and elemental characterization confirm the reversible Zn 2+ and water cointercalation electrochemical reaction mechanism. This work brings a new prospect of designing high‐performance aqueous rechargeable zinc ion batteries for grid‐scale energy storage.