Electronic interaction coupling of Fe-ZrO2 enables efficient and stable ORR electrocatalyst for long-cycling Zn-air battery

Metallic Fe single atom is an efficient catalyst for rechargeable zinc-air batteries (ZABs), but faces problems such as easy deactivation and instability in use. Here, we report a stable Fe-ZrO 2 electrocatalyst for oxygen reduction reaction (ORR) catalysis. Atomically coupled Fe-O-Zr heterointerfaces are formed by embedding Fe nanodots (around 18 nm) into ZrO 2 nanoparticles dispersed in nitrogen doped bubble-like porous carbon nanofibers (PCNFs). In this structure, Fe can share electrons with ZrO 2 to form interfacial coupling Fe-O-Zr bond as a bridge for charge transfer, in which ZrO 2 acts as electron promoter to facilitate electron transfer from Fe to the interface, thereby inhibiting the rapid deactivation of Fe and accelerating the activation and conversion of intermediate adsorbates. As a result, the electrocatalyst with a high loading of Fe (7.96 wt%) achieves a high half-wave potential of 0.868 V, with 95.3% of retained activity after cycling for 39600 s. The ZABs show stable open-circuit voltages and high capacities of 823.9 mA·cm −2 , and can stably run 1560 cycles at 10 mA·cm −2 with a round-trip efficiency of 51%, exhibiting superior cycling stability. A stable Fe-ZrO 2 electrocatalyst containing atomically coupled Fe-O-Zr heterointerfaces is fabricated for ORR catalysis. Fe can share electrons with ZrO 2 to form coupling Fe-O-Zr bond as a bridge for charge transfer, and ZrO 2 acts as electron promoter to facilitate electron transfer from Fe to the interface. The electrocatalyst achieves a high half-wave potential of 0.868 V, and the Zn-air batteries can stably run 1560 cycles, exhibiting superior cycling stability. • A metal-oxide coupling strategy is proposed to design efficient ORR catalysis. • An electronic interaction structure of Fe-ZrO 2 is designed as ORR catalyst. • The lattice interlocked Fe-ZrO 2 establishes a stable Fe-based ORR catalyst. • The Zn-air batteries show long-term stability over 1560 cycles.