Fe3Co nanoparticles embedded carbon nanotube complex as effective bifunctional electrocatalysts for rechargeable zinc-air batteries

•In situ catalytically induced generation of carbon nanotubes not only significantly accelerated the electron transfer process, but also greatly optimised the catalytic behavior.•Fe3Co1−NC catalyst exhibits excellent bifunctional catalytic activity with ORR , E1/2 =0.87V and OER overpotential at 10 mA cm-2 is 390 mV.•The DFT calculation indicates that the synergistic effect between Fe and Co optimises the ORR/OER pathway, which is in high agreement with the experimental results.•The liquid and flexible zinc-air battery presented high power densities of 189.8 mW cm-2 and 81.59 mW cm-2. Fe3Co nanoparticles have been successfully embedded within ZIF-8 derived carbon nanotube complex using a simple solvent-heated self-assembly-pyrolysis strategy, it acts as an efficient ORR/OER bifunctional electrocatalyst and showed outstanding performance of excellent catalytic activity for ORR (E1/2 = 0.87 V at 0.1 M KOH) and OER (the overpotential at 10 mA cm−2 is 390 mV at 1 M KOH). Density functional theory (DFT) demonstrates that the introduction of iron and cobalt atoms significantly impacted on the adsorption energies of the reactive intermediates. In particular, the combination of cobalt and iron exhibited significantly enhanced ORR/OER activities, revealing an enhanced effect of synergistic interaction of FeCo site for bifunctional properties. It is used as Fe3Co1−NC in aqueous zinc-air battery (ZAB) and exhibited a high open-circuit voltage of 1.52 V, power density of 189.8 mW cm−2, and long cycle durability of 400 h. Flexible ZABs assembled exhibit high power density (81.59 mW cm−2) and long cycling durability (90 h).