A Defect-Driven Atomically Dispersed Fe-N-C Electrocatalyst For Bifunctional Oxygen Electrocatalytic Activity In Zn-Air Batteries

This work proposes a strategy to synthesize N-doped defective carbon (NDC), followed by trapping the FePc precursor. After pyrolysis, the optimized Fe-N-NDC-1-900 exhibits robust anchoring ability to immobilize atomic Fe species with abundant Fe-N-4 sites, demonstrating excellent electrocatalytic activity in both the oxygen reduction reaction (ORR, E-1/2 = 0.89 V, E-onset = 1.06 V) and oxygen evolution reaction (OER, E-10 = 1.58 V). It also shows outstanding stability and delivers faster kinetics in oxygen electrocatalysis. Furthermore, the bifunctional Fe-N-NDC-1-900 is fabricated for a Zn-air battery, which demonstrates a high open-circuit voltage of 1.479 V, power density of 266 mW cm(-2), specific capacity of 786 mA h g(Zn)(-1), and excellent reversibility with long-term cycling. DFT suggests that the high ORR activity is mainly ascribed to its high electronegativity and small energy barriers, produced by the adjacent pore defects and optimal charge redistribution.