Bifunctional\nOxygen Electrocatalysts Derived from\nMetal–Organic Framework-Hydrolyzed Nanosheets for Rechargeable\nZn-Air Batteries

Abstract

The\nupsurging interest in rechargeable Zn-air batteries (ZABs)\nhas recently spurred tremendous research effort on exploiting highly\nefficient and stable bifunctional oxygen electrocatalysts. Herein,\nwe proposed a facile metal–organic framework-hydrolyzed method\nto fabricate a three-dimensional N-doped carbon nanotube material\nenriched with FeCo species (FeCo/N-CNT) showing a small potential\ndifference of 0.71 V for oxygen electrocatalytic reactions. When it\nwas used as the air electrode catalyst to assemble the ZAB, high maximum\npower density (237.5 mW cm^–2) and large specific\ncapacity (747.4 mAh g^–1) were achieved. More importantly,\nthe corresponding ZABs exhibited high cycling durability with an insignificant\nvoltage gap after the 1300th constant current charge–discharge\ncycling. Such outstanding rechargeable ZAB performance should originate\nfrom FeCo nanoparticles and Fe/Co–N co-doping species integrated\ninto well-graphitized carbon nanotubes. This study offers a novel\nmethod to prepare efficient and stable bifunctional oxygen electrocatalysts\nfor rechargeable ZABs.