Electrospun Fe, N co-doped porous carbon nanofibers with Fe4N species as a highly efficient oxygen reduction catalyst for rechargeable zinc-air batteries.

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]