Rare-Earth-Based Bimetallic Metal–Organic Frameworks Promote Oxygen Electrocatalysis for Rechargeable Zn–Air Batteries

Metal–organic frameworks (MOF) are versatile and good structurally stable materials that are widely used in energy conversion and storage. In this work, rare-earth-based bimetallic metal–organic framework (NiY-BTC) nanorods anchored with transition metal–organic frameworks (ZIF-67) were used as versatile precursors to prepare novel metal/rare-earth metal oxide-coupled carbon-based bifunctional oxygen electrocatalysts (NiY/C@Co/C). Due to the stable nanorods framework structure, appropriate Y2O3 active center, and richness of Co–N sites in the carbon skeletons, the NiY/C@Co/C catalyst exhibits high onset potentials (Eonset = 0.928 V) and half-wave potential (E1/2 = 0.83 V) for the oxygen reduction reaction (ORR), and expresses a low overpotential (η = 392 mV@10 mA cm–2) for the oxygen evolution reaction (OER). Moreover, a rechargeable Zn–air battery assembled with NiY/C@Co/C as the air cathode catalyst displayed a great specific capacity (899.6 mAh gZn–1) and a remarkable peak power density of 102.2 mW cm–2, as well as excellent durability and stability. This work delivers a way using rare-earth metal–organic frameworks to get the corresponding metal oxide-coupled carbon-based bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries.