High-performance bifunctional oxygen electrocatalysts for zinc-air batteries over mesoporous Fe/Co-N-C nanofibers with embedding FeCo alloy nanoparticles

Abstract

Mesoporous Fe/Co-N-C nanofibers with embedding FeCo nanoparticles (denote as FeCo@MNC) have been prepared from electrospun Fe/Co-N coordination compounds with bicomponent polymers consisting of polyvinylpyrrolidone (PVP) and polyacrylonitrile (PAN). The as-fabricated hybrid nanofibers exhibited one-dimensional mesoporous morphology, a large BET surface area and uniformly distributed active sites (e.g FeCo alloy, Fe/Co-N). It elucidated that the co-existence of FeCo alloy and Fe/Co-N active sites could promote the catalytic activity of ORR and OER simultaneously. Essentially, the unique one-dimensional of nanofiber with observable porous morphology has indispensable contribution to charge transportation and exposure of active sites to O2 adsorption when assembled into a rechargeable zinc-air battery. As a result, FeCo@MNC exhibited a low discharge-charge voltage gap (e.g. 0.9 V, discharge-charge at 20 mA cm−2), higher power density (e.g. 115 mW cm−2, at 143 mA cm−2) and stability.