Bifunctional Oxygen Electrocatalysts Derived from Metal–Organic Framework-Hydrolyzed Nanosheets for Rechargeable Zn-Air Batteries

Abstract

The upsurging interest in rechargeable Zn-air batteries (ZABs) has recently spurred tremendous research effort on exploiting highly efficient and stable bifunctional oxygen electrocatalysts. Herein, we proposed a facile metal–organic framework-hydrolyzed method to fabricate a three-dimensional N-doped carbon nanotube material enriched with FeCo species (FeCo/N-CNT) showing a small potential difference of 0.71 V for oxygen electrocatalytic reactions. When it was used as the air electrode catalyst to assemble the ZAB, high maximum power density (237.5 mW cm–2) and large specific capacity (747.4 mAh g–1) were achieved. More importantly, the corresponding ZABs exhibited high cycling durability with an insignificant voltage gap after the 1300th constant current charge–discharge cycling. Such outstanding rechargeable ZAB performance should originate from FeCo nanoparticles and Fe/Co–N co-doping species integrated into well-graphitized carbon nanotubes. This study offers a novel method to prepare efficient and stable bifunctional oxygen electrocatalysts for rechargeable ZABs.