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

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.