N, S co-doped carbon with embedment of FeNi alloy as bifunctional oxygen electrocatalysts for rechargeable Zinc-air batteries

Zinc-air batteries (ZABs) have sparked great interest, but their wide-ranging applications are limited by sluggish cathode reactions (ORR and OER). In this work, a multifunctional 3D catalyst (FeNi alloy/porous carbon) was easily fabricated by introducing Fe 3+ and Ni 2+ to modulate in-situ vapor phase grown carbon nanotubes. The as-prepared catalyst FNSNC73-800 displays abundant mesoporous, massive structural defects , and multiple active sites, which greatly facilitate the transport of oxygen species and charge transfer during the reaction. Due to the excellent ORR and OER performance, FNSNC73-800 shows a narrow voltage gap (Δ E ) of 0.76 V, which is superior to recent reports. Notably, the secondary zinc-air battery with this catalyst displays a high-peak power density (210 mW cm −2 ), while maintaining an ultra-low potential gap (0.74 V) after a long-term charge-discharge cycle of 200 h. This effort presents a facile strategy for designing economical and efficient 3D catalysts for zinc-air batteries and more energy devices.