Hierarchical Structure Design of ZIF‐Derived CoNiFe LDH Nanocages Grown on Ag Nanowires as High‐Performance Cathode for Zn‐Air Batteries

Developing bifunctional electrocatalysts with superior oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activity and high durability are crucial for rechargeable metal-air batteries. Transition-metal-based layered double hydroxides (LDHs) are promising in the application as cost-effective and high-performance air cathodes. Herein, hierarchical composites of Zeolitic imidazolate framework (ZIF)-derived CoNiFe LDH nanocages in situ grown on silver nanowires (Ag NWs) are synthesized as carbon-free bifunctional oxygen electrocatalysts. The hollow structure of LDH and heterointerface with conductive Ag substrate not only maximizes exposure of active sites but also ensures effective electron transfer. In addition, the hybridization with Ag induces structural disorder and unsaturated coordination in the LDH shells, thereby enhancing intrinsic catalytic activity. Theoretical calculations reveal that the incorporation of Ag species can tune the electronic states and reduce the reaction barriers of OER and ORR. As a result, CoNiFe LDH@Ag NWs exhibit a bifunctional overpotential of 0.63 V. Applied as a carbon-free cathode in a zinc-air battery, CoNiFe LDH@Ag NWs yield a high specific capacity of 808 mAh g^-1 and long cycling stability up to 300 h. This work provides new insight into the design of LDH hierarchical structure for efficient and durable electrocatalysts.