Synergistic Charge Redistribution in a Dual‐Atomic Fe−CoN ₆ on Nanofiber With Fe−N Site Preference of Intermediates Compared to Pristine Fe Single Atoms for Oxygen Redox in Zinc‐Air Battery

ABSTRACT

Reducing the reaction barriers of the oxygen reduction reaction (ORR) and accelerating the reaction kinetics of zinc‐air batteries (ZABs) requires unique advantages in regulating electron orbitals with weakened adsorption of oxygen intermediates and conductive dissociation with a negative shift of the d‐band center. The sluggish ORR and unstable Zn/electrolyte interface at relatively high‐rate ability require bifunctional electrolysis. Herein, a multi‐walled carbon nanotube (MWCNT) and resorcinol‐formaldehyde (RF) polymer composite resulted nanofiber in which Fe and Co‐atomic sites were incorporated in Fe _A ‐Co _A /MWCNT‐NC. As compared between the bridging Fe−Co and lateral Fe−Co model by Density Functional Theory (DFT) simulation and Bader charge analysis, optimal charge transfer at bridging with faster ORR kinetics as a result of balanced adsorption energy and electron distribution suggests a Fe−Co bridging model is more active. A comparison of ORR and ZAB with single‐atomic FeSA950NC supports the DFT results of charge distribution and weakened adsorption of ORR intermediates. ORR and ZAB results reveal: 1) bridging atom sites with moderate charge polarization due to delocalization of d‐band electrons, 2) significant electron conduction, 3) more adsorption‐desorption on Fe−N sites. These findings offer insights into the electron redistribution in sites of electrodes and rational design for high‐performance electrodes in energy storage devices.