Atomically dispersed iron-zinc dual-metal sites to boost catalytic oxygen reduction activities for efficient zinc-air batteries.

Developing asymmetric heteronuclear dual-atom catalysts (DACs) through coordination microenvironment regulation and investigating their structure-activity relationship for the catalytic oxygen reduction reaction (ORR) are crucial for energy conversion and storage devices such as zinc-air batteries (ZABs). In this work, a novel catalyst with its Fe and Zn diatomic sites atomically dispersed on nitrogen-doped hierarchical porous carbon (FeZn-NC-800) was designed and synthesized under a cyanamide-assisted sintering atmosphere to stabilize Zn single atoms in the structure. Benefiting from specific synergy between the Fe and Zn atoms and the hierarchical porous carbon substrate, the obtained FeZn-NC-800 catalyst exhibits remarkable ORR performance with a positive half-wave potential of 0.89 V and good durability, outstripping the performance of most state-of-the-art catalysts and commercial precious metal catalysts. Moreover, the ZABs assembled with the FeZn-NC-800 cathodes exhibit an excellent peak power density of 218.6 mW cm and achieve stable cycling for over 200 hours at a current density of 10 mA cm. This study provides a fresh new insight into the development of stable and highly active DAC materials, advancing the design of next-generation energy technologies.