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Rational design of highly effective and low-cost oxygen reduction reaction (ORR) electrocatalysts to replace Pt-based catalysts is still a significant challenge for rechargeable zinc-air batteries. Hence, Fe, N co-doped one-dimensional carbon nanofibers with Fe 4 N species (Fe/N-CNFs) are synthesized through the electrospun technique combining with the "rapid calcination under vacuum" method. Benefitting from the one-dimensional structure obtained by the electrospun technique, the as-synthesized Fe/N-CNFs electrocatalyst with mesoporous exhibits a relatively large specific surface area of 624.12 m2 g−1. Notably, the intrinsic activity of Fe 4 N species as well as the large specific surface area can endow the resulting Fe/N-CNFs with a positive half-wave potential of 0.88 V compared with 20 wt% Pt/C (0.86 V) for ORR. The Fe/N-CNFs also exhibits better long-term stability than 20 wt% Pt/C. Furthermore, the rechargeable zinc-air battery constructed with Fe/N-CNFs as the cathode shows a high open-circuit voltage of 1.51 V, a peak power density of 135 mW cm−2 and an excellent cycle life for 55 h. The as-synthesized electrocatalyst is promising to replace the precious metal catalysts for rechargeable zinc-air batteries. Unlabelled Image • Fe, N co-doped carbon nanofibers (Fe/N-CNFs) with Fe 4 N species were synthesized. • The "rapid calcination under vacuum" was reported for the preparation of Fe/N-CNFs. • The one-dimensional structure of Fe/N-CNFs provides a large specific surface area. • The Fe/N-CNFs exhibits more excellent ORR activity than commercial 20 wt% Pt/C. • The Fe/N-CNFs endows zinc-air batteries with comparable performances to 20 wt% Pt/C. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient and stable bi-functional electrocatalyst is developed by a facile foaming-assisted electrospinning method. • FeCo alloy nanoparticles are uniformly embedded within N-doped mesoporous carbon nanofibers. • The FeCo@NCNF electrocatalyst exhibited excellent ORR and OER performances with a smaller potential gap (ΔE) of 0.749 V. • The as-constructed Zn-air battery exhibits a larger power density of 134.83 mW cm−2 and long-term cycling stability after 216 h tests. A low-cost, efficient and durable bi-functional electrocatalysts for bi-functional oxygen reduction/evolution reactions (ORR/OER) is vital for modern energy conversion devices. Here, we report the exploration of advanced OER/ORR bi-functional catalysts based on foaming-assisted electrospinning. The addition of foaming agent is beneficial to prevent the agglomeration of FeCo alloy nanoparticles decorated on the N-doped mesoporous carbon nanofibers (FeCo@NCNF). These rationally designed electrocatalysts exhibit an excellent bi-functional electrocatalytic activity with a low reversible overvoltage of 0.749 V. The as-constructed Zn-air battery delivers a power density of 134.83 mW cm−2 and long-term cycling stability with a slight increase of 0.02 V in potential gap over 216 h at 5 mA cm−2, surpassing to most bi-functional electrocatalysts ever reported. [ABSTRACT FROM AUTHOR]