With the bloom of portable and wearable electronics, electrochemical storage devices featured with high performance, low-cost, safe, environmental-friendly, lightweight, thin and flexible features become more important than ever. Here, we construct a rechargeable Ni/Zn battery with a Co-doped Ni(OH)2 (CNH) and Zn materials on nickel nanowire arrays (NNA) for electrodes. The CNH cathodic material can be electrochemically deposited onto the NNA, which can deliver a high capacity of 346mAhg−1 at current density of 5Ag−1. Co doping can effectively stabilize Ni(OH)2 with only ~10% capacity loss over 5 000 charge/discharge cycles at 30Ag−1. For anode, the design of Zn on NNA considerably lowers the risk of corrosion and dendrite form ation. As a result, ultrafast rechargeable Ni/Zn batteries are obtained, exhibiting a cell voltage of ~1.75V, energy density of 148.54Whkg−1 (4.05WhL−1) and power density of 1.725kWkg−1 (based on the mass of active materials) with a charging time of <1min. Additionally, the NNA-based aqueous Ni/Zn battery exhibits superior longevity (only ~12% capacity losses after 5000 cycles). These features enable our Ni/Zn batteries a highly promising candidate for the next generation of flexible energy storage systems.