Multiscale nanoengineering fabrication of air electrode catalysts in rechargeable Zn-air batteries.

A multiscale nanoengineering strategy, simultaneously including metal nanoparticle-atomized pathway and metal-organic framework-derived approach, is developed to realize the anchoring of atomic and nanosized transition-metal species in N-doped hierarchically tubular porous carbon for high-performance oxygen reduction and evolution reactions. [Display omitted] • A multiscale nanoengineering strategy, simultaneously including metal-organic framework-derived approach and metal nanoparticle-atomized pathway, to realize the anchoring of atomic and nanosized Fe/Co species on N-doped hierarchically tubular porous carbon substrate. • Fe/Co nanoparticles and single atoms are respectively utilized for accelerating OER and ORR, endowing the obtained material with a small OER/ORR potential gap of 0.684 V. • When the obtained material is used in the air electrode, 260 mW cm-2 of peak power density for liquid-state Zn-air battery, 110 mW cm-2 of peak power density for solid-state Zn-air battery, and 1000 charge-discharge cycles without decay are realized. The development of cost-effective, high-activity and stable catalysts to accelerate the sluggish kinetics of cathodic oxygen reduction/evolution reactions (ORR/OER) plays a critical part in commercialization application of rechargeable Zn-air batteries (RZABs). Herein, a multiscale nanoengineering strategy is developed to simultaneously stabilize Co-doped Fe nanoparticles originated from metal-organic framework-derived approach and atomic Fe/Co sites derived from metal nanoparticle-atomized way on N-doped hierarchically tubular porous carbon substrate. Thereinto, metal nanoparticles and single atoms are respectively used to expedite the OER and ORR. Consequently, the final material is acted as an oxygen electrode catalyst, displaying 0.684 V of OER/ORR potential gap, 260 mW cm-2 of peak power density for liquid-state RZAB, 110 mW cm-2 of peak power density for solid-state RZAB, and 1000 charge-discharge cycles without decay, which confirms great potential for energy storage and conversion applications. [ABSTRACT FROM AUTHOR]