Advancing Flexible Zinc Air Battery: Exploring Non-Noble Metal Oxides for Enhanced Electronic Structure Modulation in...

Advancing flexible zinc-air batteries requires cost-effective, durable bifunctional catalysts capable of efficiently driving both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Here, we report a scalable reflux-calcination strategy to prepare hierarchical flower-like Fe-Mo oxides (FeMoO). The engineered Fe-O-Mo interactions effectively tune the electronic structure, lower adsorption energy barriers, and accelerate charge-transfer kinetics. Among the series, Fe_0.25Mo_0.75O (FeMoO-III) exhibited excellent OER activity with an overpotential of 240 mV at 10 mA cm^-2 and remarkable stability exceeding 200 h at 50 mA cm^-2. Concurrently, ORR studies revealed a high half-wave potential (0.86 V) and outstanding durability, confirming its bifunctional performance. When integrated into a rechargeable zinc-air battery, FeMoO-III delivered a high open-circuit voltage of 1.51 V and sustained charge-discharge cycling over 175 h. Moreover, in a flexible quasi-solid-state zinc-air battery, the FeMoO-III cathode maintained stable operation for more than 56 h at 5 mA cm^-2, underscoring its suitability for wearable energy devices. This work demonstrates that rational modulation of non-noble oxide electronic structures through Fe-Mo synergy offers a practical pathway toward scalable, high-performance, and flexible zinc-air batteries.