Rechargeable aqueous hybrid Zn batteries (HZBs) have received increasing attention due to their low-cost, inherent safety, and green characteristics. However, it is still far from large-scale practical applications due to the absence of cathode materials with high-performance and stable structures. Here, Co 1.29 Ni 1.71 O 4 nanowires (NWs) are grown on nickel foam by a simple hydrothermal method. The Co 1.29 Ni 1.71 O 4 NWs exhibit reversible redox response and high catalytic activity for oxygen reduction reaction/oxygen evolution reaction due to a freestanding nanowire array structure, which effectively exposes active materials and provides abundant electrochemical active sites. Outstanding cycling stability can be achieved at 10 mA cm −2 over an ultralong life of ∼2127 h (88.6 days) for 6680 cycles with a specific discharge capacity of 168.3 mA h g −1 in KOH electrolytes. The assembled HZB with the Co 1.29 Ni 1.71 O 4 NWs delivers a flat and high discharge voltage plateau of ∼1.65 V with Coulombic efficiency of nearly 100% and excellent rate performance. This work may pave a new way to design and synthesize promising cathode materials for application in rechargeable aqueous HZBs.

Electrochemical synthesis of NH 3 from H 2 O and N 2 , as a sustainable alternative to the Haber−Bosch process, has attracted extensive attention. However, the achievement of effective NH 3 electrosynthesis remains challenging since N 2 features remarkable thermodynamic stability and ultralow solubility in aqueous electrolytes. Here, we prepare new-type Cr-based spinel oxides using coprecipitation and hydrothermal methods. The ternary spinel ZnCr 2−x Fe x O 4 phases are formed by substituting Fe 3+ ions for Cr 3+ ions at octahedral sites of ZnCr 2 O 4 . The introduction of Fe results in lattice expansion, lattice distortion, an increase in oxygen vacancies, and a remarkable change in the electronic structure, which further affect nitrogen chemisorption and activation properties. The asfabricated ZnCr 1.2 Fe 0.8 O 4 spinel has bifunctional active sites of Cr 3+ and Fe 3+ and exhibits large capacity and moderate strength of N 2 chemisorption. To break the N 2 solubility limit in the aqueous electrolytes for electrosynthesis of NH 3 , a novel two-step process of gas-phase N 2 adsorption and electroreduction is successfully developed. The catalyst has excellent catalytic performances with an ammonia formation rate of 29.26 μg h −1 cm −2 , the highest Faradaic efficiency of 18.41%, and long-term stability for 20 h. This study provides a new strategy for developing a highly efficient electrocatalyst for the electrosynthesis of NH 3 .