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 (eta = 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.