Spatially Decoupled Single/Dual-Atomic Sites with Independent Bifunctional Activity for High-Performance Fiber Zinc-Air Batteries
The sluggish kinetics of oxygen reduction and evolution reactions (ORR/OER) at the air electrode impede the practical deployment of fiber zinc-air batteries (FZABs) for wearable electronics. Conventional bifunctional catalysts suffer from an inherent activity trade-off due to the distinct mechanisms of ORR and OER. Here, 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. The catalyst exhibits 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 based on this catalyst delivers 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.