Large-scale defect-rich iron/nitrogen co-doped graphene-based materials as the excellent bifunctional electrocatalyst...

Defect-engineering in transition-metal-doped carbon-based catalyst plays an essential role for improving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance. Herein, we report a ball-milling induced defect assisted with ZnCl₂ strategy for fabricating defect-rich iron/nitrogen co-doped graphene-based materials (Fe-N-G). The substantial mechanical shear forces and the constant corrosion to the carbon matrix by ZnCl₂ lead to the creation of abundant defects in graphene-based materials, which facilitates doping for heteroatoms. The defect-rich Fe-N-G catalyst with abundant Fe-N_x active sites displays excellent ORR performance. For OER, the over potential for Fe-N-G outperforms that of RuO₂ in 1 M KOH at 10 mA cm^-2. The Density Functional Theory calculations unravel that the impressive OER performance is attributable to the introduction of abundant defects. Additionally, the liquid and all-solid-state zinc-air batteries equipped with the prepared material as the air cathode demonstrate high power density, high specific capacity, and long charge-discharge stability. This work offers a practical method for manufacturing high-performance electrocatalysts for environmental and energy-related fields.