Isolation anchoring strategy for in situ synthesis of iron single-atom catalysts towards long-term rechargeable zinc-air battery

The reasonable design and construction of single-atom electrocatalysts with low-cost and excellent intrinsic activity for oxygen reduction reaction (ORR) is indispensable in metal-air batteries. Herein, a facile isolation anchoring strategy was reported for in situ formation of porous N-doped carbon catalysts (Fe1/NC) rich in Fe single atoms. The d-glucose, zinc gluconate and N-rich histidine were deployed as spatial isolation agents and anchoring agents to inhibit iron atom aggregation during the high-temperature pyrolysis. The as-synthesized Fe1/NC catalyst shows remarkable stability and superior ORR electrocatalytic activity under both alkaline and acidic conditions owing to highly dispersed Fe–N4 sites, especially with a half-wave potential up to 0.91 V in 0.1 M KOH, exceeding 60 mV compared with Pt/C. Notably, the Fe1/NC-based Zn-air battery exhibits maximal power density of 164 mW cm−2, large specific capacities of 769 mA h gZn−1, excellent cycle stability over 300 h, and great potential in renewable energy conversion electronics.