Spatially decoupled single/dual-atomic sites with independent bifunctional activity for high-performance fiber zinc-air batteries

The development of high-performance bifunctional electrocatalysts is crucial for advancing zinc-air batteries. However, the fundamentally distinct mechanisms of the oxygen reduction and evolution reactions (ORR/OER) hinder the simultaneous realization of high activity within a single catalyst. Herein, we propose a spatial decoupling strategy to overcome this limitation by engineering isolated Fe single-atoms and Fe–Ir dual-atom pairs on a nitrogen-doped carbon matrix (Fe/FeIr-NC). In this architecture, Fe single atoms serve as ORR centers, while Fe–Ir pairs with tunable spacing are tailored for OER, enabling complete functional separation and independent optimization of the reactions. As a result, the catalyst delivers an ORR half-wave potential of 0.91 V and an OER overpotential of 250 mV at 10 mA cm−2, yielding a record-low bifunctional gap (ΔE = 0.57 V) that outperforms all reported single- and dual-atom catalysts. A flexible fiber zinc-air battery was developed based on this catalyst, delivering a peak power density of 3920 W kg−1, along with a 1.4-fold increase in energy efficiency and a 2.6-fold extension in cycle life compared to the commercial Pt/C + IrO2 benchmark. This work not only breaks the traditional activity trade-off in bifunctional catalysis but also offers a promising route toward high-performance power sources for wearable electronics.